Monday, August 24, 2015

The For'd Thwart

"For'd thwart"... or "forward thwart." The front seat, in other words. (This nautical terminology thing is fun).

In any case, I got the basics of the thing built over the weekend. The construction is essentially the same as the rear thwart, although it was a bit trickier to measure for this one. 

With the rear thwart, I had both the frame and its cutouts for the seat risers to use as reference points. Since I did not install the full-length seat risers, (as the boat was designed to have), and since the forward thwart is mounted several inches aft of the forward frame, I first had to figure out where the seat riser should be. Then I could use that as a beginning reference point.

To get to the point, the originally-designed seat riser does not move parallel to the keel. The keel, in fact, is angled downward from the transom to the bow. The sheer line is angled upward from the transom to the deck. Who knows if the seat riser is on a level line? (I suppose I would, had I not lost the drawings at some point.)

The point is, the forward thwart is actually mounted higher than the rear thwart. The way I'm building the seat supports, the seats on my boat will actually be parallel to the keel. Based on my measurements, the forward thwart should have been some 2-1/2 to 3 inches higher than the rear thwart. Put simply, I didn't want it that high. So, I built the center support to 9" in height... one inch taller than the rear one.

Next came measuring the seat dimension from side to side. Again, not easy. To boot, the inward curve of the sides of the hull meant a considerably more angled trapezoid shape than the rear thwart. The complexity of the shape made it easy to mess up.

I won't share my dimensions here, because I measured them too short, and cut them even shorter. Executive decision: move the thing forward until it mates to the sides, rather than re-measure and cut a new one.

Actually, that was a pretty easy decision to make. Sure, it will mean that whoever is sitting up front will have to sit facing backwards, if they want to be comfortable. However, this arrangement actually maximizes the available space between the thwarts, providing the most available legroom for everyone. Besides, if I put oars on the boat, I'll have to sit backwards to row it, anyway.

Enough gabbing. Let's look at the pictures:

Opening up the center space like this should give plenty of legroom for up to 3 people in the boat. 

The sides of the forward thwart were cut at a 30° bevel to match the sides of the hull.
Oh yes, one last update: I epoxied the bow eye into place. I filled the hole up with thickened epoxy, pushed the bolt through, tightened it, and scraped away the mess. It shouldn't be going anywhere.

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