Currently the motor compartment is a mixture of epoxy
coated ply and raw wood, with lots of messy epoxy fillets showing.
Before the subdeck is fixed over the area permanently, I want to paint
it. That means smoothing out some of the irregularities in the fillets,
and taking a sander to the glassy epoxy coating to hull sides and
bottom. Even with the subdeck off, there is little room to manoeuvre in
there, and it does not take long before my legs are screaming out to be
straightened. So, I can only do a bit at a time. In between times,
waiting for epoxy or paint to dry, I cannot enter the compartment, so I
can start to glue down the rear deck strips. Doing that slowly, one
piece at a time, suits me well, as there can be no return from errors
at this stage.
The dash bulkhead prior to painting.
The dash bulkhead prior to painting.
I was happy with the black japan I used in
the rudder compartment, so I plan to use it again here for the deck
stringers and hatch supports. The hull sides and bottom can be painted
grey, like the rudder compartment bottom, and the bulkheads too,
although I will keep the instrument plinths and steering box plain. I
briefly entertained the thought of using a non-skid deck finish down
there, but I felt that its rough surface would be difficult to clean,
and this compartment will probably get dirtier than most. But I do not
want a slippery surface either, so I will do what I did on the hull
bottom, and add a flattening agent to make it a matt finish.
Black japan on the deck stringers.
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Black japan on the deck stringers.
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134. Rear
Deck Glue-Down
The coaming to stern log joint.
The first board to be secured is the short
forward piece of the king plank, which runs between the transverse
coaming and the front of the hatch opening. Both it and its
neighbouring planks are masked to prevent epoxy contamination. There
will eventually be a bollard attached over the top of the king plank,
and it would be possible to screw it down at this stage to assist in
flattening any rearmost cupping which has occurred in the piece. If it
is not too bad a simple clamp can be used instead.
It is currently cupped up off the subdeck centrally. At the junction with the coaming a pressure block can be clamped to eliminate the forward cup, and a batten to the ceiling will take care of the middle.
Green masking tape on the king plank and its neighbours.
I do not want to glue any other strips to the deck unintentionally, so I am covering the under surfaces of the neighbouring ones, and their approximating edges, with silicone baking paper. And I do not want epoxy to seal the hatch either, so it is removed, and the excess is wiped off that area. Prior experience with epoxy has made me very cautious about its runs. It seems to run and collect for a long time until it gels, so simply wiping it up once is not enough. You have to keep going back again and again.
Despite the close fitting components of subdeck and deck, I do not feel comfortable using unthickened epoxy resin as the glue here. There will be irregularities which may be too large for the resin to fill. So, I will thicken the mixture with microfibres, just to a cream consistency. Both subdeck and decking planks need to be primed with the straight resin before gluing with the thickened mixture, and the application of the bog can be sparing, but still enough to ooze out into the caulking gaps between boards, where is is scooped up carefully as it goes off.
Silicone paper, masking tape and clamps all seen here.
The areas underneath the ply washers are inaccessible to scooping tools, but the thin nature of the mix means that it will run out from under them and down the slope. If any resin runs underneath the neighbouring boards, deep to the silicone paper, it will set on top of the subdeck, so it is important to make sure that the boards are all held down securely. With the narrow ones, that can be achieved by the washers alone.
After the epoxy has gone off, but before it has set rock hard, the washers are removed, the neighbouring boards are lifted and the silicone paper removed. Any ridges of epoxy are flattened out in preparation for the next plank to be glued down, and the entire process is repeated.
With a new sense of confidence after the successful gluing of the king plank, I did the next three all together. The starboard sides were masked in blue tape to help in orientation. Once again, the process was uneventful, but it does help if you smear just enough epoxy onto the planks to allow for minimal squeeze out. Anything more risks getting epoxy all over the deck.
The king plank and starboard planks 1, 2 and 3 are all glued down here.
It is currently cupped up off the subdeck centrally. At the junction with the coaming a pressure block can be clamped to eliminate the forward cup, and a batten to the ceiling will take care of the middle.
Green masking tape on the king plank and its neighbours.
I do not want to glue any other strips to the deck unintentionally, so I am covering the under surfaces of the neighbouring ones, and their approximating edges, with silicone baking paper. And I do not want epoxy to seal the hatch either, so it is removed, and the excess is wiped off that area. Prior experience with epoxy has made me very cautious about its runs. It seems to run and collect for a long time until it gels, so simply wiping it up once is not enough. You have to keep going back again and again.
Despite the close fitting components of subdeck and deck, I do not feel comfortable using unthickened epoxy resin as the glue here. There will be irregularities which may be too large for the resin to fill. So, I will thicken the mixture with microfibres, just to a cream consistency. Both subdeck and decking planks need to be primed with the straight resin before gluing with the thickened mixture, and the application of the bog can be sparing, but still enough to ooze out into the caulking gaps between boards, where is is scooped up carefully as it goes off.
Silicone paper, masking tape and clamps all seen here.
The areas underneath the ply washers are inaccessible to scooping tools, but the thin nature of the mix means that it will run out from under them and down the slope. If any resin runs underneath the neighbouring boards, deep to the silicone paper, it will set on top of the subdeck, so it is important to make sure that the boards are all held down securely. With the narrow ones, that can be achieved by the washers alone.
After the epoxy has gone off, but before it has set rock hard, the washers are removed, the neighbouring boards are lifted and the silicone paper removed. Any ridges of epoxy are flattened out in preparation for the next plank to be glued down, and the entire process is repeated.
With a new sense of confidence after the successful gluing of the king plank, I did the next three all together. The starboard sides were masked in blue tape to help in orientation. Once again, the process was uneventful, but it does help if you smear just enough epoxy onto the planks to allow for minimal squeeze out. Anything more risks getting epoxy all over the deck.
The king plank and starboard planks 1, 2 and 3 are all glued down here.
The Gougeon Bros. book, from
which this method of planking is adopted, recommends using graphite
thickened epoxy, which would do away with the necessity of gouging out
the excess. The black epoxy is used as the caulking as well. I could
not imagine that this would not end up in a total mess in my hands, so
I am using microfibres, and will use Sikaflex caulking, even although
the boards will not move and I do not need the flexibility of Sikaflex.
It just has to be neater in the long run.
The next step is to attach the first three port side planks. After that, the hatch has to be covered, and with no more short planks left until the outer ones, is will be time to move on to the full length ones 4 to 7. While there is wet paint on the port side of the boat I can glue down the hatch planks on the starboard
Gluing the hatch (left) is followed by the port side planks.
The next step is to attach the first three port side planks. After that, the hatch has to be covered, and with no more short planks left until the outer ones, is will be time to move on to the full length ones 4 to 7. While there is wet paint on the port side of the boat I can glue down the hatch planks on the starboard
Gluing the hatch (left) is followed by the port side planks.
Another day of
gluing gets about half the deck completed. Although in theory the
screws will ensure a uniform gap between the planks, in practice there
is a bit of drift, and you constantly
have
to be on the lookout for irregularities as you screw them down. In
addition, as the shape of the deck is a kind of three dimensional
parabola, the outer planks want to cross inwards over the back of the
inner ones, so they have to be forced out. That tends to make their
middles want to wander out as well, and that has to be corrected too.
Slow hardener in the epoxy mix is a good idea for this job, as it
allows plenty of time to back out the hold-down washers, force the
plank into correct alignment, and retighten the washers to hold it
there.
With all of the hatch, pre-hatch deck, and port side complete, there only remains the post-hatch and starboard side planks to go before the stern log and covering boards can be fastened.
The last of the decking planks being glued down.
With all of the hatch, pre-hatch deck, and port side complete, there only remains the post-hatch and starboard side planks to go before the stern log and covering boards can be fastened.
The last of the decking planks being glued down.
After the
masks are removed the opportunity presents itself to put the deck
hardware on to plan its location on the finished boat. A lifting ring
will be added to raise the hatch, but otherwise this is the full
complement of accoutrements. The fairleads have to be positioned so
that any lines from the bollard do not get tangled in other
obstructions, and the stern light has to be exactly where the wiring is
located under the deck. Otherwise the arrangement is fairly free.
The finished decking planks ready for caulking.
It is not a problem, unless your boards are super thin, but it does mean that there will eventually be less wood in the middle (and more epoxy) than at the edges. So, rather than do a heavy sanding at this stage, it is better to do a light one and leave the rest for after the caulking has gone down.
Some of the traditional slipper launches have deeply rounded stern logs, whether from necessity or style I don't know. But that will not be possible for Ariadne. The constructed transom and stern log mean that there is not a great deal of wood there for rounding, and it will appear to be much sharper than the old boats. But, considering that the plans did not even have a stern log at all, I think the one I have created is a very good compromise.
A traditional rounded stern log.
The finished decking planks ready for caulking.
All
the careful alignment of the planks did not result in a uniform curve
at the rear end. There were irregularities, which had to be removed by
a pass with the router, using the stern log as a template to guide its
copying ring. The ends of the planks had to have small blocks inserted
between them to prevent tear out. After that, the stern log was glued
down with every clamp I own, which would fit, helping to close the gap
at the back.
With the stern log glued down, only the covering boards are left to complete the rear deck woodwork.
With the stern log glued down, only the covering boards are left to complete the rear deck woodwork.
One
thing to mention about the screw and washer technique of holding the
boards down is that these thin boards do buckle a bit under the strain.
The washers clamp them tightly to the subdeck at the edges, but in the
middle the accumulated epoxy raises them ever so slightly from the
subdeck. You don't notice this until you start to sand the deck, but
then you see the corrugations left behind by the planer disappear from
the middle of the board long before they do from its edges.
After some sanding, corrugations remain on the edges.
After some sanding, corrugations remain on the edges.
It is not a problem, unless your boards are super thin, but it does mean that there will eventually be less wood in the middle (and more epoxy) than at the edges. So, rather than do a heavy sanding at this stage, it is better to do a light one and leave the rest for after the caulking has gone down.
Some of the traditional slipper launches have deeply rounded stern logs, whether from necessity or style I don't know. But that will not be possible for Ariadne. The constructed transom and stern log mean that there is not a great deal of wood there for rounding, and it will appear to be much sharper than the old boats. But, considering that the plans did not even have a stern log at all, I think the one I have created is a very good compromise.
A traditional rounded stern log.
The
covering boards are being laid one at a time, beginning with the
starboard one. Again, all clamps and makeshift devices are called upon
to hold down the outboard edge, while washers hold down the inboard and
the forward end. Clamps on the coaming hold that part of the inboard
edge which lies next to the coaming.
Gluing down the starboard stern covering board.
Gluing down the starboard stern covering board.
And
its final appearance after a bit of sanding:
The
coaming to stern log joint was not completely invisible, but it is
acceptable, considering that epoxy always makes a black line. I think
the method I used is a good one, and may come in handy again when I get
to the foredeck.
The coaming to stern log joint.
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135. The
Rubbing Strake
There is some advantage in
attaching the rubbing strake early in the boat's construction, as can
be seen below.
A Freebody launch under construction.
A Freebody launch under construction.
I was not even considering
this part of the equipment when the boat was in this stage of
completion, but I did have the foresight to add some wooden backing
boards along the course of the strake on the inside of the hull before
its compartments became inaccessible They can now be used as screw
grips while the glue sets. That means that the strake has to be screwed
from the outside via counterbores which will be plugged. The gunwale
rubber is attached the same way, screwing into the hull side first, and
then the sheer strake. The plan specifies 12 gauge screws for the
gunwale rubber, but does not make mention of the lower rubber. It seems
to be about 3/4" thick in the photos, so I will use a 19 mm. dimension.
That means that the screws will have to be no bigger than 6 gauge, in
order for the counterbores to be sized correctly. They will be
spaced at 100 mm. centres.
The wood should be something tough, like red ironbark or spotted gum, or similar, the same as the gunwale rubber, and it will have to be scarfed. It will be easier to drill the screw holes and counterbores before the shape is rounded, and that means running the entire length of the strake across the drill press table, or at least each of the three lengths individually, which will be scarfed together subsequently.
The most difficult part of the strake will be its forward end, where it has to snuggle up against the stem as well as the hull side. That will be the first end to be connected, and the curve of the hull will have to be accommodated as the strake is pulled in towards it. The curve is not quite as severe at the level of the strake as it was at the sheer, but there is not much in it. I remember having to repair snapped sheer strakes three times as I tried to make them conform to the hull curve, so I intended steaming the front end of this strake just in case.
My previous efforts at steaming were simple. I just rested the parts (of the stem) over the lid of an electric kettle. For the sheer strakes, I soaked them in boiling water. On this occasion I thought it might be better to set up a proper steam jacket, and treat the entire front 2 metres where the greatest curvature is. Once that is negotiated it should be plain sailing to attach to the rest of the hull, screwing and gluing as I go. But, as luck would have it, I was fortunate enough to find a piece of Kwila with some severe bowing at one end, which was enough to allow the curve of the bow to be negotiated without steaming. It made it very awkward to cut into strips and put through the thicknesser, but it does the trick. Kwila (Intsia palembanica) is also known as Merbau here, and is half the price of the eucalypt hardwoods.
The fitting starts by cutting a piece of scrap to fit up against the stem at the level of the rubbing strake. Once a good fit is achieved the settings for the saw angles can be transferred onto one of the pieces which will make up the scarfed strake. A bit of filing and sand-papering will make the fit snug. Only after that is the strake scarfed.
The scrap fitting for the forward end of the rubbing strake.
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Problems shows higher resolution shots as well.
The wood should be something tough, like red ironbark or spotted gum, or similar, the same as the gunwale rubber, and it will have to be scarfed. It will be easier to drill the screw holes and counterbores before the shape is rounded, and that means running the entire length of the strake across the drill press table, or at least each of the three lengths individually, which will be scarfed together subsequently.
The most difficult part of the strake will be its forward end, where it has to snuggle up against the stem as well as the hull side. That will be the first end to be connected, and the curve of the hull will have to be accommodated as the strake is pulled in towards it. The curve is not quite as severe at the level of the strake as it was at the sheer, but there is not much in it. I remember having to repair snapped sheer strakes three times as I tried to make them conform to the hull curve, so I intended steaming the front end of this strake just in case.
My previous efforts at steaming were simple. I just rested the parts (of the stem) over the lid of an electric kettle. For the sheer strakes, I soaked them in boiling water. On this occasion I thought it might be better to set up a proper steam jacket, and treat the entire front 2 metres where the greatest curvature is. Once that is negotiated it should be plain sailing to attach to the rest of the hull, screwing and gluing as I go. But, as luck would have it, I was fortunate enough to find a piece of Kwila with some severe bowing at one end, which was enough to allow the curve of the bow to be negotiated without steaming. It made it very awkward to cut into strips and put through the thicknesser, but it does the trick. Kwila (Intsia palembanica) is also known as Merbau here, and is half the price of the eucalypt hardwoods.
The fitting starts by cutting a piece of scrap to fit up against the stem at the level of the rubbing strake. Once a good fit is achieved the settings for the saw angles can be transferred onto one of the pieces which will make up the scarfed strake. A bit of filing and sand-papering will make the fit snug. Only after that is the strake scarfed.
The scrap fitting for the forward end of the rubbing strake.
The angle at
which the hull meets the stem will dictate how wide the strake can be.
Below, the strake is seen jutting out beyond the stem.
If the strake is
to be terminated level with the front of the stem, a width of 15
mm. is required. If that is considered insufficient, the strake will
have to terminate into the side of the stem, as is seen in this boat:
The first coat of off-white Brightside to the port hull shows up some of the dings as much as the green did, but I expect that will mellow a little when it is dry. The dings themselves seem to have been caused by things like seat support fillets which were glued to the inside of the hull. Even 9 mm. ply gives a little at those points. The only way I can see to smooth it out completely now would be with a fairing machine, but that would mean cutting through the glass coating. I don't think that optical perfection is worth that much, and I think the minor irregularities, although they will annoy me, will not be noticed by the casual observer anyway.
Bearing in mind that the finish is only as good as the substrate on which it is being applied, I think that this Brightside paint is really impressive. The texture is very smooth and slippery, possibly because of the Teflon it contains, and the flow properties are quite forgiving. Two coats is a perfectly adequate coverage, and with the off-white, which was applied to a white base of Prekote, even only one coat is enough. I will leave it at one coat for now, in case work on the completion of the boat causes a few scratches to the hull, in which case a later second coat will cover them.
With my Kwila cut to approximate size I am able to take the front stick and clamp it onto the starboard hull. (The port still has wet paint). This is not its exact shape, because the shape of the stem/hull joint is not yet cut into it, but it is enough to get the stick ready for screw fixation. I have decided to try to try to scarf these pieces together on the hull, rather than on saw horses, so that each can be attached separately. Handling a 7 metre piece is difficult, but 2.4 metre lengths are manageable.
Having access to the forward compartments is a lifesaver too. At the front end where the tension is greatest I will be able to use bolts instead of screws. From the motor compartment back there is only a relatively mild tension, and screws will be sufficient, until the rudder compartment is reached. From there to the stern the strake has to bend down to follow the slope of the deck, but the tension there will be to flip up rather than out, so screws again should suffice, possibly aided by a sprung batten from the ceiling.
Training the starboard rubbing strake...
However, being a traditional
slipper launch, this boat has a much wider stem than Ariadne. I will
have to experiment to see what looks best. In the meantime, I have the
setting for the compound angle cut on the table saw stored away for the
real thing.
I want to attach the gunwale and rubbing strake on to the top of already finished hull sides, so I have to catch up with the paint work. So far, only the port side is near ready. The starboard is now converted to the green boot top and preparation is made to convert the top strake to green as well.
I want to attach the gunwale and rubbing strake on to the top of already finished hull sides, so I have to catch up with the paint work. So far, only the port side is near ready. The starboard is now converted to the green boot top and preparation is made to convert the top strake to green as well.
The first coat of off-white Brightside to the port hull shows up some of the dings as much as the green did, but I expect that will mellow a little when it is dry. The dings themselves seem to have been caused by things like seat support fillets which were glued to the inside of the hull. Even 9 mm. ply gives a little at those points. The only way I can see to smooth it out completely now would be with a fairing machine, but that would mean cutting through the glass coating. I don't think that optical perfection is worth that much, and I think the minor irregularities, although they will annoy me, will not be noticed by the casual observer anyway.
Bearing in mind that the finish is only as good as the substrate on which it is being applied, I think that this Brightside paint is really impressive. The texture is very smooth and slippery, possibly because of the Teflon it contains, and the flow properties are quite forgiving. Two coats is a perfectly adequate coverage, and with the off-white, which was applied to a white base of Prekote, even only one coat is enough. I will leave it at one coat for now, in case work on the completion of the boat causes a few scratches to the hull, in which case a later second coat will cover them.
With my Kwila cut to approximate size I am able to take the front stick and clamp it onto the starboard hull. (The port still has wet paint). This is not its exact shape, because the shape of the stem/hull joint is not yet cut into it, but it is enough to get the stick ready for screw fixation. I have decided to try to try to scarf these pieces together on the hull, rather than on saw horses, so that each can be attached separately. Handling a 7 metre piece is difficult, but 2.4 metre lengths are manageable.
Having access to the forward compartments is a lifesaver too. At the front end where the tension is greatest I will be able to use bolts instead of screws. From the motor compartment back there is only a relatively mild tension, and screws will be sufficient, until the rudder compartment is reached. From there to the stern the strake has to bend down to follow the slope of the deck, but the tension there will be to flip up rather than out, so screws again should suffice, possibly aided by a sprung batten from the ceiling.
Training the starboard rubbing strake...
A strake
with an oblong cross section is a drab looking thing, out of keeping
with the philosophy of the slipper launch. It can be made a little less
boxy by chamfering its sides a little to give a truncated triangle
section. A
sloping upper edge on the strake will help it to shed water too.
It will not be necessary to remove more than 2 mm. from the upper and
lower outer edges, and any more than that would compromise the screw
holes anyway.
By the time I have chamfered the sticks the port side paint is dry, so the forward component is moved over and will be left for a few days to take up the shape. Family commitments over Easter mean that little work will be done on the boat, and by the time I get back to it I am hoping that this stick will be reluctant to straighten out again. But before it is scarfed to the mid section stick its outer edges will be rounded over gently. Then, screw holes can be drilled into it with a brad point bit so that the plugs it will receive will be going into a cleanly cut shaft. A final adjustment to the forward end, once I have decided on the shape of its termination, will set it up for a permanent fit, and all the screw holes will be drilled on through the hull. The stick will again be removed, the hull sides masked, and the stick replaced, this time with epoxy
...and the same on the port.
By the time I have chamfered the sticks the port side paint is dry, so the forward component is moved over and will be left for a few days to take up the shape. Family commitments over Easter mean that little work will be done on the boat, and by the time I get back to it I am hoping that this stick will be reluctant to straighten out again. But before it is scarfed to the mid section stick its outer edges will be rounded over gently. Then, screw holes can be drilled into it with a brad point bit so that the plugs it will receive will be going into a cleanly cut shaft. A final adjustment to the forward end, once I have decided on the shape of its termination, will set it up for a permanent fit, and all the screw holes will be drilled on through the hull. The stick will again be removed, the hull sides masked, and the stick replaced, this time with epoxy
...and the same on the port.
The
decision with the forward termination is to round it into the stem. It
still looks a bit chunky, but with such a thin and narrow stem I can't
see any alternative. If the strake is carried forward to the front of
the stem it looks worse, because it is thicker than the stem is wide.
This seems like a good compromise. I need to carry the white paint on
the stem up to the top of the strake where the green will begin.
The forward termination of the strake into the stem.
The forward termination of the strake into the stem.
After
two days of drilling and bolting two sections of the strip are in
position and roughly scarfed together. I want to attach the entire
strip down one side and drill for its bolts or screws before gluing it
on. The counterbores for the fixings are cut with a 5/16" drill, and
the plugs are cut with an 8 mm. conical section cutter. This ensures a
very tight fit when hammered home.
Well,
the scarfing on the boat plan was a flop. I could not get enough
tension on the pieces with the screws into the hull, so they were all
removed and scarfed on the saw horses. I will be left with a 7 metre
length to man-handle, but at least the screw holes are all drilled in
advance.
The forward scarf is drying.
The forward scarf is drying.
Once the strake is ready for
gluing, it is returned to the hull, so that its surrounds can be masked
off. As this is newly applied paint I make sure to use one of the
expensive masking tapes which are guaranteed not to rip it off again.
The strake itself is also masked. In order not to have 7 metres of
strake flapping about with wet epoxy on it, messing up the new paint
work, I have decided to use some Sikaflex instead. This can be applied
from a cartridge gun in a bead along the hull. A little can be put into
the screw holes in the hull, but I prefer to leave the bolt holes free
of it so that the application of the washer and nut are not made
impossibly messy.
You only have one hour of open time with Sikaflex, and that is about what it takes to attach the strake. Squeeze-out should land on the masking tape and be relatively easy to remove, but a sharpened tongue depressor is on stand by if needed. Once dry, the Sikaflex cannot be removed except by mechanical means.
The masked hull and strake ready for gluing.
You only have one hour of open time with Sikaflex, and that is about what it takes to attach the strake. Squeeze-out should land on the masking tape and be relatively easy to remove, but a sharpened tongue depressor is on stand by if needed. Once dry, the Sikaflex cannot be removed except by mechanical means.
The masked hull and strake ready for gluing.
The sad fact about
marine paints is that they cannot be touched up. The entire surface has
to be covered in a single application. So, when the removal of a strake
from the hull inflicts a deep scratch on the paintwork, as this one
did, the entire strip has to be repainted. If the paint is more than
two days old, that also means that it has to be sanded again before the
next coat goes on. That is the point at which I found myself after the
strake whipped away from the hull and gouged a groove out of the green
above it. So two more days have to go by for painting, during which
time I can do little else because of the dust which might be created.
It is turning into one of those months!
Repairing a gouged top strake. This means the whole strake will need repainting with at least two coats.
With all this painting, with oil based paint, I prefer to throw away brushes after use, rather than wash them out in gallons of turps. But the availability of cheap brushes is a distraction. It seems to be impossible to find brushes which do not come from China, so it is best to avoid the ones which put you into a race to finish the job before the last bristle falls out into the wet paint. The synthetic bristles are not good for oil paints either. The soft natural hairs give the best finish.
With rollers, none is suitable for the finish coat by itself, because of the stipple. So I use a disposable foam roller, and follow it up with vertical finish strokes with the brush. You have to maintain a wet edge with this paint, so, if you are working alone, do only a small section with the roller, and immediately brush it out before the pain begins to dry. The greatest problem with the paint is that it shows up more and more flaws as it dries to a glassy finish, and in my case that means dust. The tiny dust particles are quite invisible while the paint is being applied, but after 10 minutes it starts to show, and by then it is too late to go back and smooth it out. The paint is too far gone to allow it to flow.
I have tried washing everything down with turps before the painting: rollers, trays, boat, the lot. But still I get dust. Washing the brand new brushes reduces it considerably, so I assume that I have been applying a bit of the Chinese air pollution to the hull. After painting for a while it becomes less of a problem, so I have taken to starting the work in an area where dust is not so important, towards the middle of the strip. (If it is allowed to gather at the front it will cause bubbles in the boat's name, which will be a vinyl transfer). In the middle it will not be so obvious. It just means that you have to work twice as fast, because you have two wet edges to maintain instead of one.
So, with the side repainted and remasked, the rubbing strake is finally glued on. It is a messy job, and the squeeze out is difficult to contain. While it is still wet it can be cleaned off the paint with turps, but after it has begun to go off it tends to ball up, a bit like PVA, but not as neatly. The masking tape is not really very useful. as the Sikaflex tends to run in underneath it anyway.
Squeezed-out Sikaflex, and the ball it can be rubbed into.
When the mess is cleaned away the screw holes are plugged and trimmed, and the job is basically done. There is an unfortunate flat spot where the second scarf joint sits, preventing the strake from taking a fair curve in the vertical bend, but it is not obvious to the casual observer. It can be disguised a bit by working the edges into a fair curve, but it is still there to my eye. I think the starboard will probably be better after this experience.
The rubbing strake screw holes are plugged and trimmed.
The finished strake: notice the flat spot, illuminated by the incandescent light at rear, where
the scarf joint sits.
Repairing a gouged top strake. This means the whole strake will need repainting with at least two coats.
With all this painting, with oil based paint, I prefer to throw away brushes after use, rather than wash them out in gallons of turps. But the availability of cheap brushes is a distraction. It seems to be impossible to find brushes which do not come from China, so it is best to avoid the ones which put you into a race to finish the job before the last bristle falls out into the wet paint. The synthetic bristles are not good for oil paints either. The soft natural hairs give the best finish.
With rollers, none is suitable for the finish coat by itself, because of the stipple. So I use a disposable foam roller, and follow it up with vertical finish strokes with the brush. You have to maintain a wet edge with this paint, so, if you are working alone, do only a small section with the roller, and immediately brush it out before the pain begins to dry. The greatest problem with the paint is that it shows up more and more flaws as it dries to a glassy finish, and in my case that means dust. The tiny dust particles are quite invisible while the paint is being applied, but after 10 minutes it starts to show, and by then it is too late to go back and smooth it out. The paint is too far gone to allow it to flow.
I have tried washing everything down with turps before the painting: rollers, trays, boat, the lot. But still I get dust. Washing the brand new brushes reduces it considerably, so I assume that I have been applying a bit of the Chinese air pollution to the hull. After painting for a while it becomes less of a problem, so I have taken to starting the work in an area where dust is not so important, towards the middle of the strip. (If it is allowed to gather at the front it will cause bubbles in the boat's name, which will be a vinyl transfer). In the middle it will not be so obvious. It just means that you have to work twice as fast, because you have two wet edges to maintain instead of one.
So, with the side repainted and remasked, the rubbing strake is finally glued on. It is a messy job, and the squeeze out is difficult to contain. While it is still wet it can be cleaned off the paint with turps, but after it has begun to go off it tends to ball up, a bit like PVA, but not as neatly. The masking tape is not really very useful. as the Sikaflex tends to run in underneath it anyway.
Squeezed-out Sikaflex, and the ball it can be rubbed into.
When the mess is cleaned away the screw holes are plugged and trimmed, and the job is basically done. There is an unfortunate flat spot where the second scarf joint sits, preventing the strake from taking a fair curve in the vertical bend, but it is not obvious to the casual observer. It can be disguised a bit by working the edges into a fair curve, but it is still there to my eye. I think the starboard will probably be better after this experience.
The rubbing strake screw holes are plugged and trimmed.
The finished strake: notice the flat spot, illuminated by the incandescent light at rear, where
the scarf joint sits.
136. The Lateral Covering Boards
The
inward turn of the covering boards forward of the windscreen frame
means that a board wider than the 170 mm. from coaming to gunwale is
needed. 300 mm. will be sufficient to allow for the curve, but that
means that it will have to be made up of re-glued sections again, the
same as the stern covering boards. There is no need to have the complex
curve on the ends of these ones, because there is no stern log for them
to butt against. They merely have to butt against the stern and forward
boards.
Once they are constructed and planed down to 5 mm. they are placed against the coaming, and a rebate is cut out of them to allow their forward ends to move inboard 170 mm. The inner edges will need scribing to snuggle up against the coaming, and the section forward of the windscreen will be shaped by a router following the line of the gunwale. The outer edges will be planed back to gunwale level. Glue down can be achieved by ply washers forward, and by clamped blocks on the coaming amidships. I am hoping that the presence of the rubbing strake will allow for a grip for the outer clamps, but, if not, a repeat of the rear deck technique can be used.
However, before any of that can be done the forward subdeck has to be fixed down, because the lateral covering board lies over a part of it.
Once they are constructed and planed down to 5 mm. they are placed against the coaming, and a rebate is cut out of them to allow their forward ends to move inboard 170 mm. The inner edges will need scribing to snuggle up against the coaming, and the section forward of the windscreen will be shaped by a router following the line of the gunwale. The outer edges will be planed back to gunwale level. Glue down can be achieved by ply washers forward, and by clamped blocks on the coaming amidships. I am hoping that the presence of the rubbing strake will allow for a grip for the outer clamps, but, if not, a repeat of the rear deck technique can be used.
However, before any of that can be done the forward subdeck has to be fixed down, because the lateral covering board lies over a part of it.
137.
Forward Subdeck Glue-Down
There
is nothing unique about this. It is basically a repeat of all the other
subdeck gluing procedures which have taken place. But it does mean
there will be no further access to the forward compartment. So, the
towing eye has to be secured by epoxy inside the stem section.
Also, there is still the matter of "fat ply" to resolve. It might be recalled that the published ply requirements in the plans were insufficient, and more had to be purchased. Unfortunately, the new batch was considerably thicker than the old, despite them both being sold as 6 mm. The second lot was nearer 7 mm. As a result of that, there is a step between the subdeck of the fore and mid sections of the boat. That has to be levelled. There are three ways it could be done.
The rear end of the thick ply could be planed off, or the step could be filled with epoxy and smoothed off, or 1 mm. of thickness could be routed off the underneath of the subdeck where is sits on the stringers, beams and sheer. The latter of these methods is a bit too intensive, so I favour a combination of the first two, part planing, part filling, as I did with the bow section of the hull when the problem of unequal panel thicknesses arose.
That technique on the bow has caused me a lot of headache to achieve a smooth transition for the paint, but here on the subdeck there will be a deck on top, and a good deal less fiddle, I hope.
Also, there is still the matter of "fat ply" to resolve. It might be recalled that the published ply requirements in the plans were insufficient, and more had to be purchased. Unfortunately, the new batch was considerably thicker than the old, despite them both being sold as 6 mm. The second lot was nearer 7 mm. As a result of that, there is a step between the subdeck of the fore and mid sections of the boat. That has to be levelled. There are three ways it could be done.
The rear end of the thick ply could be planed off, or the step could be filled with epoxy and smoothed off, or 1 mm. of thickness could be routed off the underneath of the subdeck where is sits on the stringers, beams and sheer. The latter of these methods is a bit too intensive, so I favour a combination of the first two, part planing, part filling, as I did with the bow section of the hull when the problem of unequal panel thicknesses arose.
That technique on the bow has caused me a lot of headache to achieve a smooth transition for the paint, but here on the subdeck there will be a deck on top, and a good deal less fiddle, I hope.
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