For an
enjoyable activity this boat building certainly takes a lot of time.
This is the beginning of the fourth year of the boat's construction,
and
even taking into account a few months lost to health problems, I cannot
claim that progress has been as rapid as I first thought it would be.
So, what has been the delay?
1. Money? So far the total cost in materials has been A$14000. That is considerably less than the price of buying a boat of comparable size, even if you could find one in Australia, which you cannot. Money is not the reason.
2. Mistakes? I have made a few, but not any which have caused anything other than short term delays.
3. Organisation? Certainly, some months have gone by while the promised helpers have failed to materialise, but I have been able to fill in the time with other tasks, albeit sometimes on the Bugatti rather than the boat.
4. Momentum? Definitely. I think the greatest time waster is the loss of momentum which occasionally interrupts the process, and which can rob me of enthusiasm and leave me floundering. It is vital for me to have a plan ready for the week or month in front of me, and to achieve more or less what I had wanted to. Delays seem to be self perpetuating.
Nevertheless, there is light visible down the tunnel, and think I will find myself at a loose end when it is all over.
The idea of turning a slipper launch into an electric vehicle is not new, but I wonder whether my faithful adherence to the Andrews model is going to be counter-productive. There are newer designs, specifically intended to get the best out of electric propulsion, but retaining the elegant overall lines of the slipper launch. The greatest draw back of the traditional build is weight. I estimate that this boat will be at least 1500Kg. Compare that with this slick looker from the Patterson Boatworks (pity about the plumb stem though):
A video of the trial run of this boat, called Elektra or Fast Electric, can be found here.
This impressive vessel is made of carbon fibre, runs on lithium batteries, etc., etc., and may well become one of the traditional classics in 50 years, but I cannot do carbon fibre, and I cannot find a ready source of lithium batteries, so I will stick to what I know and what is within my ability, and I will do it as well as I can manage to, and take some pride in a job done slowly, singly and idiosyncratically, in the old style.
118. Considerations for the Decking
1. Money? So far the total cost in materials has been A$14000. That is considerably less than the price of buying a boat of comparable size, even if you could find one in Australia, which you cannot. Money is not the reason.
2. Mistakes? I have made a few, but not any which have caused anything other than short term delays.
3. Organisation? Certainly, some months have gone by while the promised helpers have failed to materialise, but I have been able to fill in the time with other tasks, albeit sometimes on the Bugatti rather than the boat.
4. Momentum? Definitely. I think the greatest time waster is the loss of momentum which occasionally interrupts the process, and which can rob me of enthusiasm and leave me floundering. It is vital for me to have a plan ready for the week or month in front of me, and to achieve more or less what I had wanted to. Delays seem to be self perpetuating.
Nevertheless, there is light visible down the tunnel, and think I will find myself at a loose end when it is all over.
The idea of turning a slipper launch into an electric vehicle is not new, but I wonder whether my faithful adherence to the Andrews model is going to be counter-productive. There are newer designs, specifically intended to get the best out of electric propulsion, but retaining the elegant overall lines of the slipper launch. The greatest draw back of the traditional build is weight. I estimate that this boat will be at least 1500Kg. Compare that with this slick looker from the Patterson Boatworks (pity about the plumb stem though):
A video of the trial run of this boat, called Elektra or Fast Electric, can be found here.
This impressive vessel is made of carbon fibre, runs on lithium batteries, etc., etc., and may well become one of the traditional classics in 50 years, but I cannot do carbon fibre, and I cannot find a ready source of lithium batteries, so I will stick to what I know and what is within my ability, and I will do it as well as I can manage to, and take some pride in a job done slowly, singly and idiosyncratically, in the old style.
118. Considerations for the Decking
Starting
at the stern, the second layer of decking must soon be laid. The plan
calls for either a second layer of ply, or solid timber strips. I have
chosen the latter, as I want the facility of being able to choose the
pattern. Having gone to the trouble of installing a striped diagonal
lagging for the cockpit, I want to continue that design on the decking
in one form or another. Prepurchased ply will not allow me that
freedom.
The decking of the stern consists of four components:
1. The covering boards, which run in continuity with the rest of the deck lateral to the coaming, as far back as the next component,
2. The stern log, or, in this case, its representation as a transversely laid piece which will fix over the top of the curved transom in the hope of making it look like a stern log.
3. The king plank, which is nothing more than a widened central strip similar to the covering board.
4. The decking proper, which fits in between the other parts and fills the gap, so to speak.
The four components can be seen in this picture:
My rear deck is complicated by the fact that it has a hatch in it, and design considerations have to be taken into account in dealing with it, but apart from that it is a simple matter of cutting the timber and gluing it down. It is the gluing down which requires a little ingenuity, as the wood is only 5 mm. thick. Plugged screws cannot be used, and I do not fancy staple wounds to fill either. For the inner strips a variation on the Gougeon Bros. method of using pan head screws in the caulking gaps will be enough, but for the covering boards some other method will have to be devised to hold down their hull sides. I'm working on it!
The "stern log" has to be laid first, as it marks the limits of the king planks and the covering boards. It is curved parallel to the transom on its forwards edge, and this can be achieved with a router on a trammel. The same set up can be used to cut the stern ends of the covering boards so that they butt against the log perfectly. The king plank and the other decking strips are separated from the log by caulking, so they do not have to be so exactly cut as the covering boards.
The log can be held by wedged clamps, but there will need to be some traction forwards to stop it slipping sternwards off the transom. If all else fails, narrow gauge brads could be used, or even fine bronze nails, as the holes from these small items can easily be disguised, especially if the boat's name is painted onto the log, as seen above.
The covering boards look best as a single piece of width equal to the distance between the coaming and the edge of the hull, or 170 mm. They can be tapered to narrower gauge forward and aft to give the boat a more refined look, but, because they are describing a gentle curve in two planes they have to be wider than 170 mm. to begin with. I was planning to do scarf joints between the segments of the covering boards, but realistically, they are only decorative, and there is no route for water to enter because of the epoxy glue, so I think butt joints are perfectly adequate, and considerably simpler. There will be three segments on each side, making their lengths about 2.2 metres each. That will place the joints forward of the cockpit and towards the rear of the cockpit, but not at the corners. The forward-most segment will be the one requiring the widest piece of timber, as it has the greatest curve. The other two can both be under 200 mm.
The king plank is wider than the other decking strips, and can also taper if necessary. There is no set width for it, but the placement of deck hardware on it will determine the best looking width. The remaining strips have to fit into the gap left, and they have to be cut to fill the voids, which means that the outer ones have to be wedge shaped. It is difficult to get a fully detailed look at a deck from the photos, but putting two and two together from a number of them gives some vital clues.
Views of the Freebody launch, Seattle Slipper.
Actually,
the more I look at photos of the old boats on the web, the more I am
beginning to think that they are not cockbeads at all, but trenches
filled with some sort of contrasting coloured putty. Some photos are
quite convincing of this, and it would make sense not to have any trim
sticking out where it can be damaged, but, having beaded the
kickboards, I am committed now.
Certainly, in the picture on the left there is no proud beading
showing on the tangential shot of the starboard coaming, and that would
explain the very gradual narrowing of the bead on the left: it could
just be a filled trench cut with a rising router.
On the other hand, some photos look much more like proud components, such as the one below. As I say, I am committed now to the bead. I guess I can always remove them if they are a nuisance.
To get an idea of how wide they should be I just clamped the cockbeads against the coaming at various widths out of the planer, until I settled on 13 mm. They seem to go quite well with the other dimensions on the trim, and will look a lot better when the coamings and the beads are both finished with Cetol.
The beads at 15 mm. (left), and 13 mm. (right).
Beads sitting in their trenches prior to gluing.
Forward to February '09
The decking of the stern consists of four components:
1. The covering boards, which run in continuity with the rest of the deck lateral to the coaming, as far back as the next component,
2. The stern log, or, in this case, its representation as a transversely laid piece which will fix over the top of the curved transom in the hope of making it look like a stern log.
3. The king plank, which is nothing more than a widened central strip similar to the covering board.
4. The decking proper, which fits in between the other parts and fills the gap, so to speak.
The four components can be seen in this picture:
My rear deck is complicated by the fact that it has a hatch in it, and design considerations have to be taken into account in dealing with it, but apart from that it is a simple matter of cutting the timber and gluing it down. It is the gluing down which requires a little ingenuity, as the wood is only 5 mm. thick. Plugged screws cannot be used, and I do not fancy staple wounds to fill either. For the inner strips a variation on the Gougeon Bros. method of using pan head screws in the caulking gaps will be enough, but for the covering boards some other method will have to be devised to hold down their hull sides. I'm working on it!
The "stern log" has to be laid first, as it marks the limits of the king planks and the covering boards. It is curved parallel to the transom on its forwards edge, and this can be achieved with a router on a trammel. The same set up can be used to cut the stern ends of the covering boards so that they butt against the log perfectly. The king plank and the other decking strips are separated from the log by caulking, so they do not have to be so exactly cut as the covering boards.
The log can be held by wedged clamps, but there will need to be some traction forwards to stop it slipping sternwards off the transom. If all else fails, narrow gauge brads could be used, or even fine bronze nails, as the holes from these small items can easily be disguised, especially if the boat's name is painted onto the log, as seen above.
The covering boards look best as a single piece of width equal to the distance between the coaming and the edge of the hull, or 170 mm. They can be tapered to narrower gauge forward and aft to give the boat a more refined look, but, because they are describing a gentle curve in two planes they have to be wider than 170 mm. to begin with. I was planning to do scarf joints between the segments of the covering boards, but realistically, they are only decorative, and there is no route for water to enter because of the epoxy glue, so I think butt joints are perfectly adequate, and considerably simpler. There will be three segments on each side, making their lengths about 2.2 metres each. That will place the joints forward of the cockpit and towards the rear of the cockpit, but not at the corners. The forward-most segment will be the one requiring the widest piece of timber, as it has the greatest curve. The other two can both be under 200 mm.
The king plank is wider than the other decking strips, and can also taper if necessary. There is no set width for it, but the placement of deck hardware on it will determine the best looking width. The remaining strips have to fit into the gap left, and they have to be cut to fill the voids, which means that the outer ones have to be wedge shaped. It is difficult to get a fully detailed look at a deck from the photos, but putting two and two together from a number of them gives some vital clues.
Views of the Freebody launch, Seattle Slipper.
In this Freebody boat it seems
that the covering boards are pretty much of uniform width all along,
and the king planks too. The caulking is running in straight lines
parallel to the long axis of the boat. If it is good enough for
Freebody, it is good enough for me. That will be the basic lay-out of
my deck.
By trying various widths in drawings on the rear deck, the best arrangement seems to be to have the king planks 130 mm. wide, and the decking strips 65 mm. That leaves 4 mm. caulking gaps, which is perfect for an 8 gauge screw, if the hold down method is to be used. There will be 9 strips between the king plank and the covering board on the rear deck, and 10 forward. In the original design, shown below the strips were 72 mm., and there were only 8 of them, but if an alternating pattern of timber colours is to be used there should be 9. The strip width can be beefed up to 66 mm. if the caulk is reduced to 3 mm. The outer strip is only a partial width anyway, and can be adjusted to accommodate the arrangement of the inner ones.
Testing deck strip patterns on the subdeck.
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By trying various widths in drawings on the rear deck, the best arrangement seems to be to have the king planks 130 mm. wide, and the decking strips 65 mm. That leaves 4 mm. caulking gaps, which is perfect for an 8 gauge screw, if the hold down method is to be used. There will be 9 strips between the king plank and the covering board on the rear deck, and 10 forward. In the original design, shown below the strips were 72 mm., and there were only 8 of them, but if an alternating pattern of timber colours is to be used there should be 9. The strip width can be beefed up to 66 mm. if the caulk is reduced to 3 mm. The outer strip is only a partial width anyway, and can be adjusted to accommodate the arrangement of the inner ones.
Testing deck strip patterns on the subdeck.
The top of the stern log look
best at about 110 mm. of width. That requires a board of 210 mm. to
enable the cut. If the transom had been shaped on a 1 metre radius,
instead of the 2 metres which I used, the board would have had to have
been wider than that. The solid logs which are used in the traditional
construction also have to be wide enough to allow for the rebate which
accepts the decking boards, as well as what is seen outside.
A new slipper launch under construction in the Freebody yard.
The top side width of the log above is less than 110 mm., but the greater curvature of the transom means that it appears to be more substantial. Anything less than 110 mm. on my boat looks insignificant. So, the recipe for the decking is set now: 170 mm. covering boards, 130 mm. king planks, 110 mm. log and 66 mm. strips with
3 mm. caulks.
On the foredeck, even if you take the forward covering board joint as far forward as 2.1 metres from the stem, the required width of board to negotiate the bend is
320 mm. So, there will be a good deal of waste. It may be possible to extract some useful lengths from that to use on the decking strips, but it is not likely. There is almost certainly going to be a mahogany barbecue this season.
But before I can start cutting the deck components I have to glue on the coamings. Here, all the areas likely to become smeared with epoxy are masked with painters' tape.
A slightly angulated joint appears between the rear deck and the side deck, as there is a change of ply wood there. This can be sanded down later to allow for a smooth transition between the two areas. All that is really required is a suitable substrate for the attachment of the decking proper, which will cover up all manner of irregularities.
The subdeck at the port aft of the cockpit. Sanding the butt.
The side
subdeck is in two pieces, forward and
aft. Before the forward piece can be glued the forward extension of the
coaming has to be fitted. It is a lot easier to reach without the
subdeck on. In the photo on the left which is taken from above, the
carling is the timber passing immediately to the left of the conduit.
The cockpit sole is visible (carpeted), and the dash bulkhead is at the
bottom. The front end of the coaming below deck level can be seen
poking a little forward of the windscreen frame, and cut perpendicular
to its face. This makes butt joining the extension relatively straight
forward.
It is cut to fit and slid down over the carling, to which it is clamped and glued. When the glue is dry two screws are added to hold it firm.
I suppose that this piece of timber could have
been left out altogether, but it makes a nice finish, even if it will
never be seen.
The completed coaming extension.
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The old style launches had a shaped escutcheon plate attached to the cockpit side of the windscreen frame to suspend the steering column. But I do not have access to them, so have had to think up another way.
The shaped steering column suspension on an Andrews boat. And, look at the ashtray too!
The two halves of wood meet at an almost imperceptible join around the column as the nuts are tightened on the bolt.
The completed steering column support.
A new slipper launch under construction in the Freebody yard.
The top side width of the log above is less than 110 mm., but the greater curvature of the transom means that it appears to be more substantial. Anything less than 110 mm. on my boat looks insignificant. So, the recipe for the decking is set now: 170 mm. covering boards, 130 mm. king planks, 110 mm. log and 66 mm. strips with
3 mm. caulks.
On the foredeck, even if you take the forward covering board joint as far forward as 2.1 metres from the stem, the required width of board to negotiate the bend is
320 mm. So, there will be a good deal of waste. It may be possible to extract some useful lengths from that to use on the decking strips, but it is not likely. There is almost certainly going to be a mahogany barbecue this season.
But before I can start cutting the deck components I have to glue on the coamings. Here, all the areas likely to become smeared with epoxy are masked with painters' tape.
The screw holes for the screen
joint are also covered to protect them from damage until such time as
they can be plugged. Incidentally, for nearly invisible plugs I prefer
to cut the holes with brad point bits, and use a tapered plug to fill
them. When the drilling is at an angle to the face of the board, as it
is in this case, it is advisable to get a brad point bit with a long
point extending past the spurs. Otherwise, the closest spur will meet
the timber before the brad has, resulting in a jagged drill hole.
The subdeck panels on the sides are removed, and the coaming is manipulated into position with the epoxy thickened enough not to stream around too much. Then, the rear coaming is screwed on to the bulkhead, and the side ones are sequentially screwed on to the carlings, and finally the screen frame. After cleaning up the ooze I can prepare the side subdeck for its own glue-down.
When the colour match is better the plugs are almost invisible. These will be a bit obvious until the
Cetol obscures them a bit.
The subdeck panels on the sides are removed, and the coaming is manipulated into position with the epoxy thickened enough not to stream around too much. Then, the rear coaming is screwed on to the bulkhead, and the side ones are sequentially screwed on to the carlings, and finally the screen frame. After cleaning up the ooze I can prepare the side subdeck for its own glue-down.
When the colour match is better the plugs are almost invisible. These will be a bit obvious until the
Cetol obscures them a bit.
119. Side Subdeck
Glue-Down
There is
nothing remarkable about the side subdeck, apart from the fact that it
lies adjacent to the coaming, and conceals the electrical conduits. In
order not to stick it down with the coaming, it was removed, and now
that the time has come to attach it permanently, the glue squeeze out
on the top of the carlings has to be removed, if it has not already
been, and the conduits have to be fixed in place, as they will no
longer be accessible hereafter.
Epoxy will inevitably ooze out to the gap between the coaming and the side deck. If epoxy smears are to be avoided on the coaming it is wise to tape a level of protection onto the timbers before the subdeck is screwed down. Similarly, there will be some ooze out on the hull side, so the gunwale needs to be protected too. Plenty of epoxy has to be applied to the top of the gunwales, and it has to be thick enough not to sag, as there will be spots in the deck/gunwale joint where there are small gaps requiring filling. It is better to allow a bit of thickened epoxy to bulge out here, as it can be cleaned off later with a plane, keeping the line of the hull constantly rising to the top of the subdeck. It is here where the rubbing strake will have to be attached later, and there is nothing to recommend a visible glue line between the covering board of the deck and the rubbing strake. The gap should be minimal.
The rear half of the port subdeck is glued down.
Epoxy will inevitably ooze out to the gap between the coaming and the side deck. If epoxy smears are to be avoided on the coaming it is wise to tape a level of protection onto the timbers before the subdeck is screwed down. Similarly, there will be some ooze out on the hull side, so the gunwale needs to be protected too. Plenty of epoxy has to be applied to the top of the gunwales, and it has to be thick enough not to sag, as there will be spots in the deck/gunwale joint where there are small gaps requiring filling. It is better to allow a bit of thickened epoxy to bulge out here, as it can be cleaned off later with a plane, keeping the line of the hull constantly rising to the top of the subdeck. It is here where the rubbing strake will have to be attached later, and there is nothing to recommend a visible glue line between the covering board of the deck and the rubbing strake. The gap should be minimal.
The rear half of the port subdeck is glued down.
A slightly angulated joint appears between the rear deck and the side deck, as there is a change of ply wood there. This can be sanded down later to allow for a smooth transition between the two areas. All that is really required is a suitable substrate for the attachment of the decking proper, which will cover up all manner of irregularities.
The subdeck at the port aft of the cockpit. Sanding the butt.
The side
subdeck is in two pieces, forward and
aft. Before the forward piece can be glued the forward extension of the
coaming has to be fitted. It is a lot easier to reach without the
subdeck on. In the photo on the left which is taken from above, the
carling is the timber passing immediately to the left of the conduit.
The cockpit sole is visible (carpeted), and the dash bulkhead is at the
bottom. The front end of the coaming below deck level can be seen
poking a little forward of the windscreen frame, and cut perpendicular
to its face. This makes butt joining the extension relatively straight
forward. It is cut to fit and slid down over the carling, to which it is clamped and glued. When the glue is dry two screws are added to hold it firm.
The completed coaming extension.
With the coaming
complete on both sides, the forward halves of the subdeck can be glued
down, but the segments in front of the windscreen are left off in order
to make the next task easier: the steering column has to be supported
at the level of the windscreen frame.
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The old style launches had a shaped escutcheon plate attached to the cockpit side of the windscreen frame to suspend the steering column. But I do not have access to them, so have had to think up another way.
The shaped steering column suspension on an Andrews boat. And, look at the ashtray too!
In the hope of one
day being able to come upon one of the genuine articles I want to leave
the visible side of the frame clear, and attach my makeshift suspension
to the other side, which is hidden under the deck. Some sort of U-bolt
arrangement will be sufficient to take the strain off the bulkhead and
steering box, but it will not look very attractive. If it enclosed a
piece of wood between its arms it would look better, but the whole
concept needs development.
A trip to the ship's chandlers produced the compromise. A big ugly U-bolt which is wide enough to fit around the steering column and hook up to the frame. As luck would have it, the arms of the bolt fitted around one of the windscreen supports attached to a deck stringer. All that was needed was to thicken the support/stringer enough to allow some hinge brackets, which I added to the bolt, to be screwed into position.
A trip to the ship's chandlers produced the compromise. A big ugly U-bolt which is wide enough to fit around the steering column and hook up to the frame. As luck would have it, the arms of the bolt fitted around one of the windscreen supports attached to a deck stringer. All that was needed was to thicken the support/stringer enough to allow some hinge brackets, which I added to the bolt, to be screwed into position.
But first I had to do something
to make this piece of hardware more visually appealing. A wooden sleeve
was fashioned out of two pieces to fit inside the U-bolt and around the
column. A 1-5/16" hole saw made the centre cut in two pieces of wood,
and a 65 mm. hole saw made the outside cut in one of them.
Using a drawer handle router bit
with a diameter of 12 mm., the same as the U-bolt, grooves were cut
into the ring and the other piece. Both were then cut across the centre
of the circles and fitted into the bolt.
The larger piece was cross cut
to length and the structure was bolted into position around the
steering column. This is fiddly work, and could have been avoided if I
had taken the steering wheel off and simply slid the support down over
the column, but taking the wheel off is a major undertaking too, so I
opted for the fiddly woodwork.
The two halves of wood meet at an almost imperceptible join around the column as the nuts are tightened on the bolt.
It is unfortunate that the arms
of the U-bolt are not long enough to hide the thread, as some is
clearly visible from the port, but it is not too unsightly. The wooden
fill has softened it considerably.
Next, the hinges brackets were cut down to fit around a beefed-up deck stringer, and one of their holes enlarged to 12 mm. so that they could be fastened to the U-bolt support. Spacers were cut to fit around the stringer and then planed down to subdeck level. These will be glued and screwed to the stringer, and the hinges will be bolted to them from the side. The whole structure will then be made perfectly rigid by the addition of the subdeck, which will be epoxied to the top of the stringer, spacers and windscreen support blocks, thereby acting as a brace to further resist any sideways forces.
The two hinges are attached to the U-bolt and marked for trimming to fit under the deck.
Next, the hinges brackets were cut down to fit around a beefed-up deck stringer, and one of their holes enlarged to 12 mm. so that they could be fastened to the U-bolt support. Spacers were cut to fit around the stringer and then planed down to subdeck level. These will be glued and screwed to the stringer, and the hinges will be bolted to them from the side. The whole structure will then be made perfectly rigid by the addition of the subdeck, which will be epoxied to the top of the stringer, spacers and windscreen support blocks, thereby acting as a brace to further resist any sideways forces.
The two hinges are attached to the U-bolt and marked for trimming to fit under the deck.
The hinges still have to be
trimmed off at deck level, and, because they are on back to front, the
countersunk screws will have to be replaced with coach screws, but,
pending that, the column support is done, and merely needs a coat of
Cetol to blend in with the other mahogany structures in the cockpit.
If I had my time over I
certainly would not leave this step so late. It is extremely awkward
drilling screw holes into the spacers, and if it had not been for the
right angle drill chuck it would have been impossible.
The column support trimmed and fitted from both sides.
Nevertheless, at the end of
another day of metal drilling and hacksawing I had the support hooked
up to the stringer and fully functional.
The column support trimmed and fitted from both sides.
With the subdeck
reassembled the cockpit is now virtually complete, but that is only a
temporary reassembly, because the screen has still to be permanently
attached to the stringers.
The completed steering column support.
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121. Filleting the Windscreen
The windscreen is currently
permanently attached by its central tenon into the space between the
two central stringer cantilevers, and to the front of the coamings. It
is screwed onto the braces attached to the remaining stringer
cantilevers, but not glued. Small epoxy fillets now have to be run
around the brace/screen frame joints to further strengthen the screen.
The weakest component of the screen is the central post, so filleting here will be more extensive, although it can only be used on the side and underneath of the braces because the subdeck will sit on top. The fact remains that this long post will be subject to leverage forces above the level of the deck. It will have to rely on the native strength of the wood in order to resist snapping. Any front seat passenger will be strongly discouraged from grabbing the post to get up off the seat, and the design of the screen's glass will reinforce that, by ensuring that it will not be easy to grab the finial on top of the post. The glass will rise up to the top of the finial, as it does in the traditional boats.
This example may be a bit extreme, as the screen glass rises way over the top of the central post.
The weakest component of the screen is the central post, so filleting here will be more extensive, although it can only be used on the side and underneath of the braces because the subdeck will sit on top. The fact remains that this long post will be subject to leverage forces above the level of the deck. It will have to rely on the native strength of the wood in order to resist snapping. Any front seat passenger will be strongly discouraged from grabbing the post to get up off the seat, and the design of the screen's glass will reinforce that, by ensuring that it will not be easy to grab the finial on top of the post. The glass will rise up to the top of the finial, as it does in the traditional boats.
This example may be a bit extreme, as the screen glass rises way over the top of the central post.
Once again, to
protect the wood from unwanted epoxy, tape is applied along the deck
line of the windscreen bottom frame, and drip cloths are placed over
the steering column to protect the cockpit. A moderately stiff mix of
resin and microfibres is forced into the areas around the junctions of
frame and support. Small strips of light weight fibreglass are added
and peel ply finishes the fillet. These will be quite invisible, but
they are able to be felt under the dash, particularly when moving the
wheel of the spotlight, so they have to be smooth. The masking tapes
are
removed before the epoxy goes off, and there is always a small amount
of creep under the tape, especially on ply wood. For this reason I try
to tape as far down towards the work area as possible, even although
there is still another layer of decking and the beading to go on top.
Fillets under peel ply reinforce the windscreen frame.
A short batten us positioned to get a fair curve on the top of the glass. The corners are rounded and the process is repeated for the other side. Two templates (they are just slightly different) are ready to send to the plexiglass cutter.
The finished screen dummies.
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Fillets under peel ply reinforce the windscreen frame.
With the
screen securely fixed I can proceed to fill the screw holes on the
cockpit side of the bottom frame. Again, snug plugs are used for an
almost invisible glue line. The colour difference between the new and
old wood will get less with time.
Snug plugs for the bottom frame.
Snug plugs for the bottom frame.
And
while I am making adjustments to the windscreen I take the opportunity
to take the rasp to the side frame finials to blend them onto the
coamings. The screen is now ready to have some dummy glass fitted so
that the real thing can be cut from them.
The blended and softened finial.
The blended and softened finial.
Making up windscreen dummies is
simple. I have been using rough cut corner plates to protect the screen
frame up to now. These pieces are now adjusted for a precise fit in
each corner, and the distance between them is recorded. Their shapes
are then transferred on to a piece of ply and it is shaved to achieve a
tight and full depth fit into the frame.
Inner and outer corners are fitted...
...and then the full sized template.
Inner and outer corners are fitted...
...and then the full sized template.
A short batten us positioned to get a fair curve on the top of the glass. The corners are rounded and the process is repeated for the other side. Two templates (they are just slightly different) are ready to send to the plexiglass cutter.
The finished screen dummies.
Top of Page
122. Final Fit-Out of
the Motor Compartment
123. Pre-Screen Subdeck Glue-Down
The glue-down of the side subdeck is now carried up to the pre-screen segments. A bit of extra care is needed here because any squeeze out of epoxy can run down into the cockpit, so a slow setting hardener is used and a sharpened spatula lifts off any extra as it appears. The line between the windscreen bottom frame and the pre-screen segment is actually unsupported for most of its length. Only at the cantilevers is there a resting point for the subdeck. Thickened epoxy is packed into the joint along the bottom frame. It is very difficult to gain access to this area underneath, otherwise a fillet would be a good idea.
The largely unsupported joint between pre-screen subdeck and windscreen bottom frame is filled with epoxy.
From the decking point of view,
all is now ready
for the small segments in front of the windscreen to be glued down.
However, I recall that the last time I was working in the engine
compartment when the subdeck was in place I squeezed into such a tight
spot that I popped a disc in my neck. I am keen to avoid a repeat of
that, so will now remove the forward subdeck and ensure that everything
in the compartment is finished. That means completing the electrical
circuits by installing the controller and the contactor, the recharger
and battery cables, and replacing the temporary electrical loom covers
of ply with Perspex, and painting the compartment if that is the best
option. After that there will only be a few hook-ups of deck hardware
like lights and horn, etc.
A stitched-up panorama of the inside of the motor compartment.
Top of Page
A stitched-up panorama of the inside of the motor compartment.
The motor
compartment has not been visited for some months. As a reminder, this
is the state of play:
There is a space between the steering box (in the centre) and the throttle (behind the red wires, left) which is big enough to house the controller and the contactor. The red wires is question are running to the "secret" switch in the cockpit, one from the downstream pole of the shunt for the main ammeter, and the other lying loose, ready to be plugged into the controller.
The white lead on the left is the CAT5e networking cable which joins the throttle to the controller.
The black lead is the radio antenna.
The purple lead hanging loose is for the spotlight.
There is a space between the steering box (in the centre) and the throttle (behind the red wires, left) which is big enough to house the controller and the contactor. The red wires is question are running to the "secret" switch in the cockpit, one from the downstream pole of the shunt for the main ammeter, and the other lying loose, ready to be plugged into the controller.
The white lead on the left is the CAT5e networking cable which joins the throttle to the controller.
The black lead is the radio antenna.
The purple lead hanging loose is for the spotlight.
Many controllers
need to have heat sinks, and the Sevcon is no exception. The
instructions do not specify what sort, except to use a metal plate, as
large as possible, and to use thermal compound on the base of the unit
the make proper contact. I plan to mount the heat sink on a
perforated wooden base with free circulation from below, up behind and
through to the top, so that any heat can be more readily dissipated.
The wooden base will be attached to the bulkhead, and the heat sink and
controller to the base. As can be seen in the pictures above, one of
the main cable runs for the domestic system passes above the area
designated for the controller, so I want to position the base at a low
level to avoid mishaps with the wiring. The lower you go, the narrower
the space becomes, so it will be a compromise between the size
available for the base unit and the dimensions of the space.
The thermal compound may have to purchased at a tech. store, as it is most commonly used for joining computer CPU's to their heat sinks. Application methods vary, but the important consideration is to achieve a clean and uniform layer of compound between the controller and the sink. Having a perfectly flat sink is, therefore, a necessity. If an aluminium plate is to be used it has to be thick enough not to warp and lose its flatness. Old thermal compound residues can be removed with alcohol should it become necessary to replace it.
The controller has a number of safety features, including measures for protection of itself from thermal overload. In the case of temperatures rising to dangerous levels there will be a reduction of current, starting at 75°C. At 90°C there is current shut down. The unwelcome prospect of losing motor power just when it is most needed, say in pushing through a strong current at maximum throttle, means that it is very important to establish a reliable heat sink mechanism. Hence, the trouble taken at this point is well worth the time.
My supplier for the controller is waiting for a new connector to allow him to program it from his computer, so it will not be finally installed until February. In the meantime I can get on with the base construction, and then finish up in the cockpit.
The base is made of 9 mm. marine ply, to which four 9 mm. feet have been added. It is perforated in the area of attachment of the heat sink, which is a bit larger than the footprint of the controller. It fits in between the steering box and the throttle, where it will eventually be screwed and glued.
The base under construction...
...and in position.
The thermal compound may have to purchased at a tech. store, as it is most commonly used for joining computer CPU's to their heat sinks. Application methods vary, but the important consideration is to achieve a clean and uniform layer of compound between the controller and the sink. Having a perfectly flat sink is, therefore, a necessity. If an aluminium plate is to be used it has to be thick enough not to warp and lose its flatness. Old thermal compound residues can be removed with alcohol should it become necessary to replace it.
The controller has a number of safety features, including measures for protection of itself from thermal overload. In the case of temperatures rising to dangerous levels there will be a reduction of current, starting at 75°C. At 90°C there is current shut down. The unwelcome prospect of losing motor power just when it is most needed, say in pushing through a strong current at maximum throttle, means that it is very important to establish a reliable heat sink mechanism. Hence, the trouble taken at this point is well worth the time.
My supplier for the controller is waiting for a new connector to allow him to program it from his computer, so it will not be finally installed until February. In the meantime I can get on with the base construction, and then finish up in the cockpit.
The base is made of 9 mm. marine ply, to which four 9 mm. feet have been added. It is perforated in the area of attachment of the heat sink, which is a bit larger than the footprint of the controller. It fits in between the steering box and the throttle, where it will eventually be screwed and glued.
The base under construction...
...and in position.
A visit to an
aluminium engineering shop secured be a piece of 10 mm. thick aluminium
plate which will serve as the sink. It will have to be cut down to the
size of the base and attached to it. I think the best option for its
attachment will be aluminium rivets if I can get any long enough.
Otherwise, plastic sleeved bolts will avoid a galvanic reaction between
any non-aluminium fastener and the plate itself.
The aluminium plate heat sink.
The aluminium plate heat sink.
Top of Page
123. Pre-Screen Subdeck Glue-Down
The glue-down of the side subdeck is now carried up to the pre-screen segments. A bit of extra care is needed here because any squeeze out of epoxy can run down into the cockpit, so a slow setting hardener is used and a sharpened spatula lifts off any extra as it appears. The line between the windscreen bottom frame and the pre-screen segment is actually unsupported for most of its length. Only at the cantilevers is there a resting point for the subdeck. Thickened epoxy is packed into the joint along the bottom frame. It is very difficult to gain access to this area underneath, otherwise a fillet would be a good idea.
The largely unsupported joint between pre-screen subdeck and windscreen bottom frame is filled with epoxy.
To add extra strength later, I
will cut the decking strips at a more acute angle than necessary to
meet the bottom frame, and I will pack some more epoxy into the gap
that that will create.
Actually,
the more I look at photos of the old boats on the web, the more I am
beginning to think that they are not cockbeads at all, but trenches
filled with some sort of contrasting coloured putty. Some photos are
quite convincing of this, and it would make sense not to have any trim
sticking out where it can be damaged, but, having beaded the
kickboards, I am committed now.
Certainly, in the picture on the left there is no proud beading
showing on the tangential shot of the starboard coaming, and that would
explain the very gradual narrowing of the bead on the left: it could
just be a filled trench cut with a rising router.On the other hand, some photos look much more like proud components, such as the one below. As I say, I am committed now to the bead. I guess I can always remove them if they are a nuisance.
To get an idea of how wide they should be I just clamped the cockbeads against the coaming at various widths out of the planer, until I settled on 13 mm. They seem to go quite well with the other dimensions on the trim, and will look a lot better when the coamings and the beads are both finished with Cetol.
The beads at 15 mm. (left), and 13 mm. (right).
Beads sitting in their trenches prior to gluing.
It
is easier to get glue off finished wood that off raw, so there is no
reason not to coat the coamings with their Cetol before the beads are
glued in. Any squeeze out will come away without a fuss. After a single
coat, the coaming is beginning to look as though it belongs on the
boat, and the bead is glued into its trench. While the glue is drying
it is held in by clamps where their throat depth is sufficient to clear
the top of the coaming, and by sprung battens forward where the
coamings are at their widest.
After a single coat of Cetol on the coaming.
Clamps and battens hold the beading in.
After a single coat of Cetol on the coaming.
Clamps and battens hold the beading in.
After
two coats of Cetol the coamings are blending in with the rest of the
mahogany on the boat, but it is quite a bit brighter in colour than the
older wood. That will mellow with a bit of age, as the timber
naturally darkens anyway.
The beading on the kickboards is a bit narrower than that on the coamings,
and that accentuates the perspective of depth in the cockpit.
The beading on the kickboards is a bit narrower than that on the coamings,
and that accentuates the perspective of depth in the cockpit.
One
thing I have noticed is that the top of the coamings is very easy to
dent. Even just a clamp lying over on its side against the wood will
leave a visible linear impression. Imagine what some buffoon will do if
he decides to step on it! I have been toying with the idea of topping
the coaming with a thin strip of something like ironbark, but that will
cause all sorts of bother at this stage, not least from getting the
transverse member flat enough to take one. At the moment it is shaped
by hand. It also causes a bit of difficulty at the screen joint. I may
just have to accept that the boat is already on its way to being an
antique.
With the installation of the cockbeads it is time to try to blend in some of the other colours in timber with the chosen highlights. A lot of the ply has been trimmed with a eucalyptus known as red mahogany, which retains a red colour despite some prolonged exposure to the atmosphere. And there is some unfinished Oregon, notably behind the rear seat back. These are now blended in with the rest of the boat's colouring by the judicious use of Cetol, and the cockpit is looking good to me. Only the windscreen frame still needs finishing.
The rear seat space now (left), and before finishing (right).
The completed and fully varnished cockpit.
With the installation of the cockbeads it is time to try to blend in some of the other colours in timber with the chosen highlights. A lot of the ply has been trimmed with a eucalyptus known as red mahogany, which retains a red colour despite some prolonged exposure to the atmosphere. And there is some unfinished Oregon, notably behind the rear seat back. These are now blended in with the rest of the boat's colouring by the judicious use of Cetol, and the cockpit is looking good to me. Only the windscreen frame still needs finishing.
The rear seat space now (left), and before finishing (right).
Next, the screen
frame is give a coat of Cetol, and there is an
immediate problem with the recently sanded areas showing up a lot
lighter than the rest. This will probably become a lot less apparent as
the wood ages again, but it will take a year or so. Also noticeable is
the difference between the screen frame and the coamings. Again, this
is a function of ageing, and should abate with time.
The completed and fully varnished cockpit.
There is still the
matter of the two under-dash shelves which fit in the forward corners
of the cockpit. They seem to lie about one third of the way down to the
sole from the windscreen frame, and they were traditionally just a plain shelf with a chrome
lip. More recently, they have dispensed with the lip in favour of
stemmed drinking glass holders.
A Freebody Slipper Launch.
A Freebody Slipper Launch.
The trouble for me
is the throttle lever. On the driver's side of the boat is comes to
rest in the full forward position just where the shelf would sit, and
will obstruct access to it. They are not strictly necessary, because
there are glovebox compartments for stowage, although the glovebox on
the non-driver's side is partly filled by the bilge pump hose, so does
not have as much space available. These finishing touches can be
delayed until the vital parts of equipment are in place, and I will see
what sort of area is available for the shelving after the seating is
finished next month.
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