Clipper's Vera Cruise Build

Clipper's Vera Cruise Build

Sunday, February 22, 2015

Short Update On Bottom Work And Some Frustration

I was hoping to have more progress to report on for this posting but it will have to be limited to a short update.

The main accomplishment was that I completed the bottom battens. All of them are in place now. The process of installing the port side was similar to that of the starboard side. I installed one batten at a time to avoid the need to rush. Using the ratchet straps at the front to pull down on the battens was extremely useful in holding them in place while I added screws.

Here are several photos showing the final work.







Most of the remaining time was taken up by various cleanup activities. This primarily consisted of filling in all the screw holes in the side skins and sanding them smooth. I also cleaned up all the excess glue from installing the battens. Finally, I encapsulated all the limber passages since these will be nearly impossible to get at once the skins are on.

All of this prep work was so that I could start adding the bottom skins. And indeed, today I endeavored to get somewhere with this. However, working alone, revealed some limitations in my ability to control the large sheets of plywood. This was further exacerbated by a lack of suitable clamping areas.

It is true that all of the bottom framework is still open. However, I decided to start by fitting the forward most skin first. In this area, nearly all the clamping points are at angles to the skin, making it tricky to get the clamps to stay in place.

I started off by lacing the full sheet of plywood on the boat and very roughly marking where I need to remove excess material. Then this was trimmed off with the jig saw. This last photo is the result.


As can be seen, I am quite a ways from having a fitted skin panel. I spent several hours today wrestling with this piece, gradually trimming away more material. The curve on this part of the boat are fairly severe, so getting the plywood to conform is not easy. The edge that matches up to the side skins is not a straight line, so it overhangs at the ends. This edge will need to be trimmed to match the side skins.

However, this is not an easy task because if the panel is bent to conform to the hull curves, it wants to lift up in the center along the side skin edge. I am trying to find a position were most of the panels lies naturally in position, but as mentioned earlier, getting it to clamp into position has been a struggle.

I had been trying to avoid using any screws to hold the panel down and this certainly made the clamping and positioning more difficult. I have come to the conclusion that using screws to hold the panel down is going to be a necessity. But by the time I reached this conclusion, it was getting rapidly colder in the garage and my patience was worn out, so I decided that giving it a break was the best course of action for now. Since we are expected to get several days of freezing weather, I will spend the time thinking about this with perhaps small tasks to keep the process going.

So that's it for now. I am determined to get these skins on and I will continue to tackle this until it's done. The good thing is that once the forward skins are on, the remaining skins will be much easier, especially the aft skins by the transom.

Until next time, take care.

Sunday, February 8, 2015

Bottom Battens Part 1

Before the bottom skins can be applied, the remaining bottom structure must be completed. This means the battens. Battens are the longitudinal pieces that run fore and aft and provide additional stiffness to the bottom skins.

On this boat (and many of the other Glen L designs), the battens are partial, meaning that they do not run the full length of the boat . I am not sure about the reasoning behind this, but I suspect at least some of it has to do with the difficulty in getting these pieces to conform to the curves up front.  I have seen other designs that use a narrower batten width and all of them run from the transom to the stem and connect on both ends.

On my boat, the plans call for 3 inch wide battens. The inner most one (closest to the keel) runs from the transom to just past frame 5. The middle one runs to just past frame 4, and the outer one (near the chine) runs to past frame 3. The amount of batten past the frames varies with the outermost extending the farthest past the frame. These loose ends are intended to eventually be attached to the skin but needs to be loose so that they will conform to the curve of the skin.

Before I could install these parts, I had to do some minor fairing on the bottom and I also wanted to see just how good the fit of the ends of the battens would be when lying against the skin. The one that concerns me most is the innermost batten. It extends past frame 5 into the extremely curve bow section and must not only bend back down , but also twist outboard (more on this in a minute).

In order to test the fit of these parts, I had to first insure that the skin would lie down flat. This is where the minor fairing on the bottom came into play. Frame 5's bottom edge still needed some trimming and sanding in order for the skins to take a nice curve around the frames and boat.

This took about two hours of attaching and checking where the interference was, removing the skins and sanding down the interference and then checking the fit again. After about four tries I had it where I wanted it.


Then, I had to clamp the battens in place and test the fit of the skin over the loose ends of the battens. Since they are not attached on one end, they tend to stick out straight from the last frame they are attached to. This straightness interferes with the skin fit to varying degrees. As mentioned before, the innermost batten has the worst fit.

After clamping the scrap piece of plywood in place, I took a look at the batten fit and was pleased to see that the outer two battens laid up against the skin nice and flat. Just what I was hoping for. In the following photos you can see a gap where the skin lies on the other batten and the keel, but this is simply because I was not applying an external pressure on these areas. I did test these areas to insure they would fit correctly and they only need a minor amount of downward pressure to fit perfectly.




However, the innermost batten was definitely going to be a problem. It only extends past the frame about 10 inches so it is fairly stiff at the end. You can see that in the following photo.


In this photo, looking at the batten end on, it appears that the batten lays in the same general plane as the frame curve, but it sticks straight out and that is where the problem lies. You can also see the difficulty I had in clamping this in place. This is only the fitting. When I glued it up it took four clamps and a ratchet strap to hold down while I added the screws.



There are a few ways to deal with this fit problem. One is to do what is called kerfing; basically slicing a slot in the end of the batten back to the frame. This slot is cut crosswise through the end of the batten from the end.. What you are after is two thinner pieces that can be bent more easily.

I wasn't sure this would work on my battens because of the short length past the frame, so I was reluctant to make the cut in the part. I tried experimenting on a scrap piece of lumber similar to the batten material and I didn't feel confident in this approach. I do know that other's have used this approach with success and it is called out as one option in the "Boatbuilding With Plywood" book I have.

 A second option is to use steam on the end and apply the twist and a slight downward bend. After studying the part in place for quite awhile, I feel like this is the approach I am going to use. The part only needs a slight outward twist at the end and a slight downward bend in order to fit under the skin. If necessary and this doesn't work, then I will kerf the ends.

Today, I decided to begin installing the starboard battens. At first I thought this was going to go quickly because of the limited gluing areas, but the difficulties with clamping and the fact that I had to repeatedly crawl under and through the boat to do the work made the first batten (the innermost one) take several hours to get into position.

The main difficulty was in clamping the front end down while I added the screws to hold it permanently. As with other parts of the boat structure, these are attached with a combination of epoxy and screws, so I was also fighting the pot life of the epoxy. I finally used a combination of clamps (some to hold the other clamps in position) and a ratchet strap to get the batten in it's correct position.

Screws were added and then the excess glue was cleaned up. The middle batten and the outer batten went in easier, although the middle batten also required a sister batten on it's inner edge. This sister batten is so the motor well sides (which will be added at a future date) will have a way to tie into the boat structure. This sister batten required a bit of extra work to get into proper position.

All three of the battens also have backing blocks under the aft end that reinforce them at the transom. This reinforcement is needed because of the limber passages I cut in the battens (see last week's posting).





So after several hours , I ended up with the starboard side battens completed. I still need to let the epoxy cure and then do a bit of clean up on them, but they are in position. It also looks like the inner most forward end may actually need less tweaking than I originally thought, but I won't know for sure until I can test the fit in a few days.




One other thing I've started doing is getting the side skins ready for fiberglassing. There is quite a bit of work that needs to be done before this can occur. The first step is to fill in all the screw holes with epoxy. So I filled the holes on two of the starboard skins. These will be sanded smooth before any of the other prep work is accomplished. I'll cover more of that in the future. Since there are so many holes to fill and I am not particularly fond of sanding, I am doing this in stages.



So that's it for this week.  I basically have to repeat this entire process on the port side. I will also be doing a lot of sanding. So the next several weeks may have less "photogenic" material to show. At any rate, I am happy to get this one side done and I look forward to getting the skinning completed.

Until next time, take care.

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.