Pretty much the last bits of boat to build and install are the two skegs on the bottom of the hull. These provide a stable base for the boat while on the trailer or beach and also are handy handholds to right the boat if capsized.
I looked through my bits of wood laying around and didn't find any solid stock that was inspiring, so I decided to build these from standard ACX plywood. Two thicknesses of 3/4" ply is the right thickness, and as these will be completely fiberglassed I think they will hold up just fine. And if not, I can always replace them with something else.
Working with the sheet plywood means that I won't have to splice parts together, and it should be easier to build parts that are straight. Any voids I find I plan to fill with epoxy.
The first step in the process was a trip to the local newspaper, where I bought an end-roll of newsprint. I unrolled a length and layed out the pattern for the skeg based on dimensions in the plan addendum.
I then perforated the pattern with an ice pick and mallet to transfer the curves to a piece of masonite, which I then cut out with a jigsaw.
I faired the curves with block plane and sandpaper and the result is shown here on the hull:
With the pattern made, I could trace out the four pieces I needed to cut. Another alternative would have been to cut out and finish one piece, and then trace from that.
I used a jigsaw to cut the four pieces to rough shape,
And laminated the two pairs.
I was careful to ensure the glueup was straight. In the foreground you can see a tall bar clamp applying a bit of down pressure, in the middle a stack of plywood cutoffs supports the center, and in the background the tips are under a ladder step to bend them down a touch. I used a 4-foot level as a 'straight' reference before all the clamps were in the way.
Here are the rough glued up parts in approximate location on the hull. I'll next bring the edges down to final dimension, fill a couple voids in the ply with epoxy, rout finger grips in the sides, and round over the edges that are not in contact with the hull.
I'm thinking I will fiberglass these off the boat, since it will be easier to work on them. When they are finished I'd then install them with epoxy and fillet them generously to the hull. I'm thinking right now that I do not need to apply fiberglass tape to those fillets, and that will save time finishing that area.
Very nice solution. The leading part of my skegs are just a bit too abrupt, although a fair curve. The problem that causes, although they are beefy and strong up front, is that they tend to hang up on the aft bunk rollers of the trailer if it is not quite deep enough in the water. Even a concerted pull with the winch and bouncing may not pop them free to ride up and forward. When I've got the boat off the trailer, probably for painting the bottom with proper antifouling, I'll remove the UHMW strips from the skegs and take my grinder to them to create a shallower slope. FYI, mine look more like a quarter circle and the aft end of the curve being about 40 mm from a vertical line from the leading edge. In fact, it looks very much like the Plans Addendum shown here http://smallcraftadvisor.com/SCAMP14Rev.pdf From your photos, yours look shallower and are probably fine but you may want to review.
ReplyDeleteThanks, Simeon. I did take the dimensions from that addendum, except for the gentler front curve which you noted. I intentionally drew that in that way, since I had read about yours getting hung up on the rollers. Also, I wanted a curve that was easier to bend the 1/4" thick UHMW strips around.
ReplyDeleteI'm wondering if adding a rub strip on the bottom of the hull on centerline from the front point back, maybe 1 1/4" wide, 18" long, and 1/2" thick or so would be of any use? It would be easy to do at this point. I just don't know whether that part of the boat hits the beach first, or because of the curve of the hull doesn't get much wear. Any thoughts on that?
Thanks - Dave
See my pm on this subject. After a year have not seen much wear here. Perhaps a bronze or ss half-round along the stem from the hull bottom up to the top of the garboard plank. There is often a lot of debris (log type) in the water around here but so far I have seen no damage on Noddy.
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