Bob's Boat Building Blog

Centerboard, Trunk and Handles

Over the past few weeks I’ve been working toward getting the centerboard trunk built and in place.  The centerboard trunk is a sleeve formed by several layers of fiberglass impregnated with epoxy.  The centerboard is used as the form.  Several layers of newspaper are wrapped around the centerboard followed by a layer of wax paper.  Then the layers of fiberglass are wrapped around that and allowed to dry.  Of course before any of that could happen the centerboard needed to be re-built.  Notice the pattern of the wood in the centerboard.

Next, to mount the truck the thwart needs to be be built and put in place.  The thwart is an arched seat that goes from side to side through the middle of the boat.  I cut strips of wood to match the pattern of the centerboard and build a jig to bend and glue the thwart together.  I tested the jig before slathering the wood with epoxy.  Worked great.  Recognize the pattern?

There are 14 individual board that go into the thwart.  I only have a few minutes to get them glued and ready to be clamped in place.  That’s how I got THWARTED!

Slow and intermittent progress over the last several weeks.  I had to take time off from the boat to go to Greece for two weeks, poor me , pictures at www.rbhphoto.com/gallery/greece.  Most of the work before and since the trip have been finishing up the bow seat and side seats.  The hole in the bow seat is for a four inch deck plate to access the area underneath for storage.  Nothing terribly interesting or exciting in the process, epoxy, fillet and fiberglass work.  Oh, and of course sanding.  Reminds me that when I told my niece Kate, a carpenter, about the project I said, “sounds like fun, hu?”  She said, “sounds like a lot of sanding”.  She was right, but it’s fun too.

Next up is a bunch of work to build the centerboard, rudder and thwart.  The centerboard that I built had some splitting issues and I need to start over.

I installed the two gussets that strengthen the area under the bow seat.  These turned out to be an unexpected challange.  The underside of the gusset is attached to the hull with fillet and fiberglass.  Applying fillet upside down in a confined area that I could not see was not much fun.  I figured out too late that the fillet mixture was too thin, what a mess.  Had to do it in two sitting letting a first coat dry and then applying a second.  Still need to fiberglass before attaching the seat.

Ben, this is for you, a picture of the recessed cock drain in the seat end.  I used a block of solid wood and set the receiving nut in fillet.  The next day I glued it to the inside of the seat end.  Then added fillet around the block on the inside of the seat.  I’ll add fiberglass inside and out later.  Probably not as exciting as you hoped.

I also got a good start on the daggerboard. Edge gluing all these pieces together with dowels and epoxy was quite the mess but worth it in the end.  A handle will be added to the top and the edges need to be sanded and tapered like a fin.  Then I can start working on forming the trunk.

Seems like a lot of little things since the last post.  The corner knees are glued in place, so I’m done with them for a while.  The bulkhead is also installed, filletted and fiberglassed. The strongback is in place.  The strongback is the horizontal solid wood piece in the picture that sits between the bulkhead and the bow.  The aft end will be trimmed flush with the bulkhead.  The mast will push against the strongback while we are underway (that means sailing for you land lubbers).

The side seats need to be vented to prevent damage from expansion due to heat (or so the plans say).  So I’ve been spending time thinking about how to do that with something that won’t get lost, like a cap, or scrape a leg while moving around in the boat.  I’ve settled on recessing a small drain cock in the seat end.  That is one of this weekend’s projects.

I’ve also started crafting the centerboard.  I need the centerboard to form the trunk it slides into.  This is done by wrapping several layers of newspaper around the centerboard,  then wrapping that in wax paper, then wrapping that with several layers of epoxy saturated fiberglass.  Installing the trunk is probably a few weeks away, but I seem to be at a point where there are small things that require gluing and waiting a long time before moving to the next step.  So I’m starting work on parts that can be worked on ahead of the sequence in the plans.

Today I worked on getting the bulkhead positioned.  The bulkhead is the vertical wall in the front of the boat that the mast will stand against and the back edge of the bow seat will rest on top of.  Since the bulkhead is perpendicular to the side seats I built a jig of sorts to provide a brace for the bulkhead while fitting it to its correct position.  I used the bow seat top and a carpenters square to get it just right.

I also did the inlay on the corner knees.  No goof ups! In this pictured you can also see that I put the cleats on the bulkhead that will provide the attachment for the bow seat.

Next time I will set the corner knees in place and move on to the outer shears.  These are wood straps that wraps around the outside of the boat.  These will be done in the dark mahogany and will be a nice contrast with the lighter spruce of the inner shear.

Quite a bit of time this weekend getting the corner knees ready to install.  The corner knees are difficult because two side slant into the boat as the knee is set in place. Another side is constrained as well.  So I’ve been following a process of sanding a little, checking the fit, sanding a little, checking the fit…  It’s slow and patience is not my strong suit.  It took several hours but now I have them cut to fit and ready to install.

But wait!  I want to inlay a bull”s eye on each knee.  If you recall from my experience with the breasthook it took me several tries to get right.  Oh boy, this is where I try to remember, it’s a journey, it’s a journey, it’s a journey…

Sanding and testing the fit can get a bit old, so I did take some time to finish the fillet and fiberglass on the seat sides,  The seats are almost ready for seat tops.  Last thing before that is finding and installing vent valves so when the boat is not is use the airtight chamber under the seat does not get damaged due to air expansion.

The knees and seats finish up the work on the back of the boat for a while.  I’m looking forward to working on the bow area.  Yes, I know its a pun, did you?

Last weekend I laid down the fiberglass reinforcements on the inside of the chine, the keel and part of the transom.  Of course there was more fillet work to smooth out some transition areas around butt blocks and battens.  Transom to planking seams needed fillet work too.  This was all in preparation for installing the seat sides that extend from the transom to the seat end.

The seat sides were installed in two sittings, first the aft connection to the transom then the forward end to the seat sides.  This is because the seat sides needed to be persuaded into the correct shape.  I used a bar clamp across the top of the seat sides to hold them tight to the motor board.  At the bottom of the seat sides I used a knotted rope threaded through the holes to pull the bottoms tight.  I then glued them in place with epoxy and fillet.

Now that the days are getting longer I was able to do the other end of the seat side after work on Thursday.  With the aft ends now secured firmly in place it was easy work lining up the forward ends.  The bottoms were tacked in place with small finishing nails and the tops were held with a short piece of lumber to wedge them tight.  More epoxy and fillet and done with seat sides.

This Saturday I added the seat cleat to the side planking that you can see above the chine between the seat end and transom.  This completes the four surfaces the seat top will sit on.  I also did more fiberglassing to the remaining parts of the transom and the joints at the seat ends.  Fillet and fiberglass is required at every junction, so there is going to be a lot of fillet and fiberglass to come as the forward bulkhead and bow seat are installed.  Fortunately I am getting comfortable with these materials.

Today there was no progress on the boat.  I golfed for the first time in over six years.  With any luck I won’t be in traction tomorrow

I have been worried about laying down fiberglass for a while.  It seemed to be the step that could easily turn into a frustrating and difficult to recover from mess.  All kinds of scenarios played out in my mind stemming from the fact that the epoxy only has a short pot time.  That means from the time it’s mixed till the time the fiberglass is saturated and applied is, well, short.  Fortunately all the worry was for naught, well mostly, I’m sure it helped me think though the plan of attack.

I started with what I predicted were the easiest sections, the chine forward of the seat ends.  These sections are short and the angle between the side plank and the bottom is shallow.  I was not sure how much epoxy the fiberglass would soak up so I made enough to be sure I could cover two layers on one side.  I also cut fiberglass for the other side incase I has underestimated the amount of epoxy and time needed.  It turned out I had underestimated both and was able to put down both layers on both sides.  I still had leftover epoxy and was disappointed I hadn’t laid out other part to glue with the extra epoxy.  I think there is some saying about crying over spilled epoxy but it evades me right now.

I got more ambitious when I moved on to the chine aft of the seat ends.  I mixed 50% more epoxy and planned on getting both sides.  The sides are longer and have steeper anges.  There are also other obstacles.  The butt blocks that connect the fore and aft parts of the side and bottom planking mean it’s not continuously smooth for the entire length of the chine.  I got two layers down on one side and only one down on the other before I ran out of enough epoxy for the final layer.  This time I had laid out other parts for spare epoxy and was able to use the leftover to edge glue boards that will be used for a corner knee.  Then I mixed a small batch of epoxy for the final layer and did some more extra glueing.  All in all a pretty successful first fiberglass experience.

I also spent some time this weekend on the port side corner knee.  This part needs to be carefully crafted to fit exactly.  I am using my belt sander to slowly remove material as I fit it in place.  The problem is that as it lowers into place it is forced forward by the slope of the transom and at the same time toward the center by the slope of the side plank.  The notch for the inner shear makes the going more complicated as does the motorboard.  If I take too much material it means I need to start over.  Recall the breasthook took me four tries, I’d really like this to take only one.

Last couple of days have been continuing the filletting process.  Now that I have a few batches under my belt I’m through the too think thick and too thin mixtures and finally hit on the Goldilocks blend.

There is enough fillet in place that I could remove most of the stitching from the chine. To do this I used my grandfathers pliers and screwdriver.  I also used these pliers to cut the stitching wire and twist the wire in place.  Though he is long gone I get great pleasure from using his tools.  As I work I am filled with the memory of his (and all my grandparents) love for me.  I am lucky to have had them for as long as I did, well into my 20s, and I’m grateful to have these tools to remind me of them from time to time.

Next step is fiberglass tape which I hope to try this weekend.  I have some questions about best practices on this step that are not clear from the instructions.  Hopefully I’ll get some answers from the boat builders forum.  If not I’ll work on the corner knees or more fillet.

It’s hard to believe it’s been over a month since I last visited the boat.  But between very cold and nasty weather (for Palo Alto) and other relationships time does seem to go by.  Today I spent a few hours sanding down epoxy and fillet in preparation for applying fillet with the correct curvature to the keel, stem and chine.  The existing fillet seen in the previous pictures was needed to set the keel lamination which the extra applied to the stem.  The final application of fillet needs to be smooth and curved correctly so the fiberglass tape can be molded cleanly to it for maximum strength.

I still haven’t gotten the hang of getting the fillet just right.  I think so far all my batches are a little too thick.  Not so bad that it was not workable, but I think working it is harder then I’d like it to be.  May just be the nature of the beast.  Also, quantity has been a challange.  Luckily I decided to make half as much as I estimated for today’s work.  By the time I finished working it into place it was getting stiff and starting to dry.  There was not enough to do everything I wanted, but at least I didn’t have a big block of fillet left over.

I was able to fillet the keel forward of the butt blocks, the stem and the port chine.