Week 17/18 - Transom / Mast

Until now Glóey's raked transom consisted of 2 sheets of 1/2" marine ply. This was a very rigid and formstable solution but now it was time to cover the plywood with the final sapele mahogani veneers which are 1/4" strong.
We selected a nice straight grained board and glued the whole transom together out of 4 pieces. A shootingboard and a Nr.7 jointerplane did an excellent job to get an absolutely tight fit.


The transom veneer then was glued with epoxy by using the vacuum bagging method.

With other words... we used the atmospheric pressure to get the transom veneer best possible flat on the transom.

The photo on the side shows the setup relatively well... there is an external vacuumpump and through a plastic-hose the air got sucked out of the polythenebag which is sealed around the transom.


Inside the bag there is a breathercloth, and a perforated releasefilm.

After mixing the epoxyresign with it's hardener we've let the pump run for about 6 hours to make sure it is cured enough.
Before glueing we screwed the transomveneer fast with 2 screws which were positioned under the future nameplate. 

There were just no really good clamping-possibilities and it should absolutely not move also not when the vacuum starts shrinking the bag.

And this is how the transom looked finally with the nameplate on. The last one is waterjet cut out of a 3mm piece of naval brass, one piece fixed with 4 screws and easy to take off when refreshing the varnish in the future.

The mast was another part that was fashioned parallel to the transom.
We used Douglas Fir which is very long grained and even stronger than Sitka Spruce. But it is also quite a bit heavier.
The mast consists of 8 strips that were machined with a so called birdsmouth.


When fitting them together it forms an octagon.
This method creates a hollow and very stiff mast.

All strips had to be extended with scarfjoints to reach a total length of about 6.3m.

Inside The mast we bedded a nylon tube for the electrocabel of the toplight and several massive wooden cores were mastbands could be fitted.
When glueing the birdsmouthconstruction with jubileeclips two opposite joints were left glueless to first get 2 halfs. This is the way how to access the inside.

To get a nice and smooth round surface of the mast the workingprocess is the same as earlier described on the post about oarmaking.

The mast is tapered and it has 2 diameter steps or rebates which help to keep the bronze mastbands in place.

At the bottom end the mast is shaped square to fit into a tabernacle with a pivotingbolt. This solution makes it easier to rigg the boat.

The crucial point here is to avoid loads on the bolt when the mast is in use... the hole for the pivotingbolt is a little oversized so that the pressure on the bolt gets relaxed as soon as the mast reaches the upright position... from that moment on the loads are stepped down to the tabernaclegroundplate.



The tabernacle is an own design which is drawn in CAD. It is fashioned out of 8mm strong pieces of 316 stainless steel plates that were lasercut directly from the CAD-files.
I welded the parts with a TIG welder and let the whole tabernacle through a sand- and finally glas-blasting process which resulted in a smooth silvergrey finish.



On the photo below the mast is sitting in the tabernacle and all 6 turning-blocks for halyards etc. are mounted on the groundplate.