Clipper's Vera Cruise Build

Clipper's Vera Cruise Build

Sunday, February 1, 2015

Working The Bottom

It's been a busy several weeks, I only wish I could say the busy applied to the boat. However, the time didn't pass completely unproductively. As mentioned in the past, the bottom structure needed to be built up, installed, and some additional fairing accomplished before the bottom skins can be fitted.

Also necessary, is completion of the work necessary to facilitate drainage. I had planned to add two drain plugs in the transom, at the lowest point. These drain plugs would be the exit point for any water that makes it's way to the bilge via the limbers channels I cut in the frames. Readers will remember that these were at every frame point and allowed water to run aft. There are additional limbers needed to allow crosswise flow and I will cover those in a moment.

Since I am planning on veneering the transom after completion of skinning, I wanted to get the drain plug holes drilled before installing the bottom skin. This is mainly because it is easier to do it now than later. A 1 inch hole saw was used because this is the outside diameter of the brass tubes that are part of the drain plug assembly.

Here are the two holes with the brass tubes in place. The tubes will not actually be installed until after the hull is fiberglassed, but with the holes drilled, I can come back later and drill out the veneer using the holes as a guide.

And here is what it looks like with the drain plugs in place. The plan is connect both of these plugs together inside the boat with lightweight chain and feed it out the holes to the plugs. This way, they cannot be lost  should they come loose. Of course, I don't want them coming loose while the boat is in the water, but they will usually be removed when the boat is out of the water (to allow drainage).

Next up was getting the battens ready for installation. I needed to cut them to final length, and add an angle on the forward half (more on that later).  This is one of the two shortest ones. I took the time to sand the upper edges so that they will be more finished when I eventually return to them after the boat is flipped. Easier to sand the edges now than later when the skin is in the way.

I found that the transom batten notches were not quite deep enough for the battens so I had to do some trimming on them. The amount was approximately 1/16", not much, but difficult to do because of the already applied transom skin.  

What I ended up doing was drawing a line on the forward face to indicate the extent of cut I wanted to make and then using a multi-tool with a straight saw blade, I cut shallow notches at 1/8" intervals in the batten notch. Then I used a chisel to remove the excess wood. This is the same technique I used last year when notching the frames for the chine and sheer. A bit of filing afterwards and the battens fit nice and flush in the notches.

The final part of the drainage work was to cut crosswise limbers in the aft end of the battens. These limbers were cut using my router and a round cutting bit. I wanted the limbers to be in a specific location in relation to the transom so I did some measuring and came up with a line measured from the end that I could line up a piece of scrap wood on. This would serve as a guide for the router. 

Then I needed to establish the correct depth of cut. There is more to this which I will cover in a moment, but, the cut must not exceed half the thickness of the batten. I went a bit safer and cut about 1/16" short of half way through.

Since this cut can weaken the batten, something has to be done to restore the strength. The standard practice on this is to install a backing of the same same thickness and material on the opposite side of the batten. This is what I planned on doing. 

The backing butts up against the transom, therefore it needs an angle cut on that end to match the angle of the transom.  On my boat, the two outermost battens are halfway over the corner frame gussets on the transom, so these had to have an angled notch cut on them to match the height of the plywood gusset. The other backings had a simple straight angle cut.

The backing also needs to extend forward a sufficient amount for strength. Finally, I cut another sharper angle on the forward edge so that the thickness of the backing flows down to the batten. When all of this is installed, it will be glued together with epoxy. or additional strength, I will later drive a couple of screws at an angle down trough this backing into the transom. I will do this after the hull is flipped.

Here is what it looks like with everything in place. This is repeated for all six battens. You can see the backing underneath the batten.

At first, I thought the next step would be to determine how difficult it would be to bend the fronts of the battens down to get the skin to lie down correctly. The battens will have to be twisted a bit as they move forward. They will also be angling downward as you get closer to the front. But even with all of that, the very ends are going to be sticking up into the area where the skins will be mounted.

The plans call for cutting an angle on the forward ends of the battens, which is what I did. However, after getting them in place, I realized that I am going to need to make a larger radius in the very end. Currently it is a fairly sharp point and this will almost certainly be a stress point on the inner skin. A larger radius will spread this out a bit.

I am also going to have to do some fairing on the frames and outer surfaces of the battens. At the aft end, there is very little (if any) fairing needed, but near the front there will be more work required. This is going to take some time and I am certain that I will not make my deadline of completing the skinning by the end of this month. But, it is a necessary step and I am not going to cut any corners.

So determining the fairing needed is the next step in this process, that and doing the necessary work. I'll cover that next time. Take care.

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