A Thousand Miles A Thousand Things to do.

Graham is hosting a Mess-a-bout in Vandemere, North Carolina on October 28, 2011. I would really like to be able to take Skorpa. I am not sure if I can have the boat finished. Time seems to be slipping away. I am putting in a lot of hours but progress though steady is still slow.

A few things like the forward deadlight, oar locks, compass, bow sprit, things that can easily added later I am leaving for now. I am still trying to do good quality work.

My mother told me to stop being so fuddy duddy and just finish the boat. She would like to see my work while she is still around.

The top sections of Skorpas masts are hollow wooden spars covered with carbon fiber braid.
Never having done a birdsmouth spar before I thought I would practice on a mast crutch that sits in the mizzen mast step during transport and holds the aft end of the two masts.


That is a view of the top of the mast crutch. It is two inches across. To make those cuts accurately I did a little work on my table saw.

The old metal insert is all bent and banged up and the opening is two large. I tried to straighten it. Then decided to make a new out of some plywood.

I put on a new blade and ran it up through the plywood insert making the cutout no larger than necessary.

When I bought my plywood I also bought some sitka spruce. It is light and strong.

The board on the left is the rough sawn wood I started with. After a lot of work I was down to some staves 9 feet long, 7/16 of an inch thick and tapering from 1 and 3/8 to 7/8 of an inch. All to make a tapered hollow wooden spar.

 One of the staves is running through the saw. Two passes one on either side of the fence makes the birdsmouth cut.

Decking

After Jim helped me get the large forward deck section glued down I worked my way steadily towards the stern.

I precoated the underside of each panel with two coats of epoxy.
I glued in 6mm ply under the butt joints in the deck. Under where the oar locks will go I set in some 5/8 solid wood to help distribute the loads.

At first the coaming structure felt fragile. Graham wanted to keep the weight down as much as possible so there is not a lot of extra in his scantlings. I was amazed and pleased though at how stiff and strong the coaming and side decks felt when everything was glued up.

Here is a view of the coaming before the side deck went on. The solid wood is only 5/8 by 5/8.

Graham told me I would want my oars to be at least 10 feet long. Since I added a lazarette the cockpit is only open for 8 feet or so. The solution is to build some tubes into the lazarette that will let the oars slide in and keep any water out.

I am wrapping some wetted out 6 oz glass onto a section of 3.5 inch aluminum tubing. I first covered the tubing lengthwise with one inch strips of plastic then wrapped that with plastic. When the epoxy sets up I slid the plastic out first then the fiberglass tube slipped off easily.

The tube is very light and was fun to make. I probably did not use enough glass, but what can you do.

The rear deck has its two coats of epoxy on the underside and is waiting to be glued in place.

 All the decking except for a small piece in the bow is in.

Tabernacle

What is a tabernacle doing on a boat? In lay terms a tabernacle is the dwelling place of the sacred.
On a ship a tabernacle is a structure on deck that holds the mast on a pivot that allows the mast to be lowered.
When you want to install the mizzen mast on an EC22 you pick the mast up and insert it through the mast partner and into the mast cup. The main mast is too heavy to install by hand so we are building a tabernacle. I have done some searching online to discover why the word tabernacle has come to be used to indicate this pivoting mast support, but I have not found anything convincing.

Here are the parts laid out.

The tabernacle goes just forward of the forward bulkhead. The mast must pivot through the deck so the forward compartment is always open. The floor slopes forward and there is a little drain near the bow. The forward compartment is a good place to store an anchor and line. I put a layer of 2 oz glass down to resist abrasion and water. The deck is reinforced on either side of the notch where the tabernacle fits.

Some temporary braces are holding the tabernacle while the epoxy sets up.

A little help from my Friend

Our good friends from Virginia Jim and Jerryanne stopped by for a brief visit. While they were here we went for a lovely sail in some gusty winds, and Jim helped me put the foredeck on.

The deck is upside down on the bench. The underside has received two coats of low viscosity epoxy.

Jim is spreading thickened epoxy on the deck beams while I mix up another batch.

If you look closely you can see epoxy spread on the deck beams. I used a notched trowel to even out the coating. In the foreground you can see some of the reinforcement for the tabernacle.

Here comes the deck epoxy still sticky.

Trying for an accurate touchdown so we don't smear the epoxy everywhere.

There she is now let's strap her down.

Cam straps hold the deck down to the curve and steady it. Small adjustments can be made but it is not sliding all over the place.

Foredeck is in place. Temporary screws hold the edges down.



Thanks Jim.

Did I show you my knees?

Knees on a boat are a framing part that carries a load around a bend. A knee connects two parts at a right angle or nearly a right angle. On Skorpa I am using knees to connect the deck beams to the side of the boat.

The curved part of the knee that faces the inside carries a compressive load. The upper part of the knee and the deck are in tension when a load is applied. The middle of the knee is not doing too much mostly just keeping the side in compression separate from the side in tension. The holes make the knee a little lighter without detracting much from their strength. They also make a handy place to tie things. And the holes make the knees look nice. I may have gone a bit overboard drilling holes.

Knees support the side of the cabin and the cockpit coaming.

The knees in the cockpit coaming have special holes to provide wiring to the compasses and for a tiller line to run the perimeter of the cockpit.

Deck Beams

Here you can see the forward deck beams in place. The aft forward deck beam is in the background with the front of the cabin resting on it. The center forward deck beam is just forward of that and five small beams run for and aft on top of the main beams.

Here is another view.

The cabin side deck beam is visible. This piece was a little tricky to fit because it bends slightly as it comes around the side of the cabin.

Aft Forward Deck Beam

Just the sound of this particular part of the boat sounds crucial to me. The Forward Deck or Fore Deck is the upper area of the boat in front of the cabin. The aft forward deck beam is the most rearward of the forward deck beams. It ties the the forward part of the cabin into the deck and supports many of the other deck beams.
At this point anyway I think of the aft forward deck beam installation as heralding the final phase of  the building of SKORPA.

The AFDB is constructed of plywood and Doug Fir. The plans have a full size pattern for the plywood, but since I have extended my cabin forward 6 inches the AFDB had to move forward as well. Since SKORPA is not at all shaped like a box the beam had to be altered to fit its new location.

This step involves gluing solid stock 1/2 by 3/4 inch to the plywood to make a composite beam If you look carefully you can see that I used scraps of wood to form cantilevers so I could develop clamping pressure near the center of the table.

Next the beam is installed in the boat just at the front edge of the cabin which is suspended by a rope to the ceiling. Actually you can not see the rope holding up the cabin but you can see two other ropes. One is holding the AFDB up in place while the epoxy sets and the other is applying a little pressure inward on the gunwales.

The Aft Forward Deck Beam is in place and the forward part of the cabin settles nicely on her and becomes part of the boat.

The center forward deck beam uses plywood only for the knee part that transfers the load over to the hull. The span is constructed of five pieces of cedar laminated with epoxy. I mad a mistake with my measuring and built the first CFDB without enough camber. I considered soaking it and trying to put more bend into it or adding some spacers but in the end I decided to build a second one. Consequently I have lots of photos.

Each strip is coated with a low viscosity epoxy.

Then thickened epoxy is spread on one surface using a notched trowel.

Then the pieces are stacked one on top of the other. As you can imagine this can get messy. Thickened epoxy has some of the properties of grease.

My form consists of a series of block clamped in place on the plastic covered table. The position of these blocks determines the camber of the beam.

Clamps are added to squeeze the layers together and to keep them all pressed flat against the table.

There is a delicate balance. You should have enough epoxy evenly spread on the parts. The pieces need to be held flat to the proper shape and squeezed together hard enough to get some squeeze out but not so hard that most of the epoxy is squeezed out and you have a starved joint.

There is normally some spring back when the beam is removed from the form. The narrower the strips and the more flexible the wood the less spring back occurs My beam straightened out less than 1/8 inch..