Clipper's Vera Cruise Build

Clipper's Vera Cruise Build

Sunday, May 31, 2015

More Bottom Skins - Almost There And Something New

This seems to go on forever. But the end is in sight. The remaining bottom skins are fitted and mostly trimmed and ready to install. I am in process of installing the butt joint backing plates, only being delayed because I underestimated the number of silicon bronze screws I would need and had to order more. I'll get back to this in a moment.

In the last posting, I was fitting the second middle bottom skin and had mentioned that I was going to seek help in getting that one installed. My friend Clark came by early on a Sunday morning and we accomplished that. Having a second set of hands around made a huge difference not only on the quality of the install, but on reduction of my stress levels.

As with all previous installs, I used stainless steel screws and plywood washers to do the initial install and then replaced the screws and washers with silicon bronze screws after about an hour's wait. It looks rather ugly here. But all is good.

Here it is after cleaning up the excess epoxy and filling in the screw holes. I'm afraid my friend Clark, being somewhat younger, has the edge on me in appearance! Or maybe it's just the camera.   :)

The remaining skins are approximately 5 feet in length and are much more manageable. Furthermore, this area of the hull is relatively flat making the fitting and install an easier process.

Since there will be no remaining structure to clamp to during the install, screws will have to be used for the entire process. However, I was able to use ratchet straps to do the initial hold down while I marked the structure on the inside of the skin.

As mentioned earlier, I am in process of adding the butt joint backing plates. These are simply the same plywood material as the skin but cut into sections to fit between the battens. There are glued into place on the existing skin and will be ready for the final skin installs.

Since I have to wait a bit for the new batch of screws, there are still two more backing plates to install. This also precludes me installing either of the skins. However, the hardware should be here early this week so I can resume work soon.

In the meantime, I am starting to plan on the next steps, namely the decoration of the transom. I have planned for some time to apply a hardwood planking over the plywood on the transom. This is going to be a decorative layer and will serve no structural purpose. I think that a bright finished transom will set off the painted hull quite nicely.

In order to do this task, I needed to determine what type of wood and how much I needed. I had originally planned on using mahogany or possibly some other exotic hardwood. My wife also suggested I look at oak. I went to the lumber yard and picked up samples of oak and cherry. They didn't have mahogany there that day so I substituted a piece of African mahogany for that sample.

I also purchase one color of gel stain to try it out. The reason for the stain is because the appearance of the stain would affect the final choice of wood to be used. Here is the first set of test samples. 

There are two samples of African mahogany because I had two different examples of that lumber, and I wanted to see how they both reacted to the stain. From the right, they are stained with the same color, American Oak from General Stains, except for the third sample which is unstained. The first two on the right are simply different wait times.

Interestingly enough, the oak was too yellow for my tastes (with this stain). The cherry looks nice but more on this in a moment. The African mahogany samples had a nice red look to them, however the third from the top has almost no difference between the three applications. The bottom sample has more differences but they are subtle.

When I started thinking it through, I realized that for continuity of appearance, I should use the same material to cover the transom as I am planning on using for the cabin sides. Since I am not planing on using plywood for the cabin sides and therefore no decorative planking, the choice of wood has to be structurally suitable for boat construction. This rules out the use of cherry wood. 

I am going to try another stain color to see how it appears, but I am tending towards the African mahogany with the current stain or perhaps no stain at all.

The other part of this process is determining how much material I need. To do this, I needed to measure the transom, determine the desired width of the boards, and then do some calculations.

The material used will be 1/4 inch thick. This allows me to hollow out the back a bit to cover the two knee bolt heads and still have material remaining. I can also use the router on the ends to round them over for a nice finished appearance.

After measuring the vertical height, I determined that each plank will be 4-3/8 inches. I looked at other widths, but liked the 4 inch width the best. 

I'll be covering this process more in the future, but the plan is to use staples to hold the wood in position while the epoxy cures. From other builders I have determined that the staple holes can be made nearly invisible after they are removed if I am careful. Of course I will be testing that first.

For now, that is all there is to report. Until next time, take care.

Sunday, May 10, 2015

Middle Bottom Skins Fitting And Install

The two middle skins on the bottom are the largest pieces to be installed. They have a slight curve from chine to keel, easily handled by the plywood. However, at the front, because of where the forward bottom skins end, there is a slight bend downwards in addition to the curve.

This additional downward bend made the butt joints more challenging than I had originally anticipated. This area at the front could be pulled in but only using screws with nuts and washers. Regular wood screws by themselves were insufficient to do the job. 

This meant drilling holes through the skin and backing plates.I was reluctant to do this but in the end had no choice. It turned out that the holes were easily filled when completed. Since the bottom and side skins will be eventually covered with fiberglass, the small holes were not going to be a problem.

On the port skin, I did have a problem with the two forward corners which didn't pull down because of insufficient clearance between the skin and the other installed skins. I decided to cut a small section out and examine the glue joints. Fortunately, the glue joints were solid except in the very corners. The areas I removed were still within the bonding areas of the backing plates and the chine and keel. 

So I cleaned up the area where I removed the corners and replaced the sections with fresh plywood epoxied into position.

 The rest of the skin went down well enough but did require a considerable amount of time to install. The port skin actually took me longer than the more difficult skins at the front of the boat. Part of this was the extra area that required epoxy (three battens in addition to the backing plates, the keel, and the chine). Part of it was the extra time needed to pull in the skins with the screws and nuts (mentioned previously).

 The repairs mentioned above were performed a couple of days after the skin had been epoxied and screwed into position. I also filled in the screw holes and countersunk screw heads with epoxy. Then everything was sanded smooth.

 I spent some time thinking over the install and realized that it was a mistake to try an install something this large by myself. So I have made arrangements to get some help when the starboard skin will be installed next weekend.

I also wanted to avoid the problems I had with the corners on the port skin. That skin had been installed from back to front because I had tried using placement blocks to set it's position and I thought I should try "walking " the panel down to the curve at the front. However, the problem with that approach was that it didn't allow any margin for error in the front fit which led to the corner problems.

Therefore I decided to do the starboard skin differently. This would be installed from front to back, insuring that these critical fit areas were done first. This also gave me more leverage as the skin was laid down because of the length going back and the relative flatness of the remainder of the structure.

Finally, I wanted to allow a little more "wiggle" room for the fit so I loosened up the joint tolerances a bit.

Working from the front to back worked out well during the fitting process. I was able to get the transition joint to fit properly as well a the corner by the keel and the other skin. Since the curve of the panel is at the front and then immediately flattens out, I had the advantage of leverage from the panel. Any adjustments needed in getting the panel to lie flat worked them selves out as I moved aft.

The starboard skin was going to need additional trimming at the keel joint for the entire length. I performed this using a multi-function  tool and a cutting blade. Basically, working a foot or two at a time (starting from the front), I would trim off excess material (but not to the final cut). This allowed me to better see how much remaining material needed to be removed.

Then I would make a second smaller removal which got me close to the final cut. The remaining cut was then performed using a 90 degree air powered die grinder and sanding disk.

 This took most of my time today because I was forced to work on my knees on top of the boat which I could only stand to do for about an hour at a time. Eventually, I completed the trimming and the panel now lies flat across the entire bonding surface. Even better, this time I have alignment marks in place to allow a front to back installation when I do the glue up.

The only disadvantage to the front to back method is that I am going to have to support the aft and middle of the skin (with epoxy already applied) while I fasten down the front before moving aft.Since I will have a helper this time, I anticipate this to go smoother.

The remainder of this week will be spent in catching up on excess glue clean up on the inner surfaces of the skins. On the port skin, the install took so long that I was not able to scrape off the excess on the inner surface like I usually do. This excess will therefore have to be sanded to have it removed.

So that's all for now. I know that the readers out there are probably getting tired of skinning articles. I am equally tired to doing them. Fortunately, after this next install, I only have the two remaining shorter (and flatter) aft bottom skins. But this skinning was originally supposed to be completed by the end of February. It now looks like the end of June before I will be completed, possibly slightly sooner. Sigh!

Anyway, until next time, take care.