Cockpit Prep and Backing Blocks

Backing Blocks for Hardware

 

(to start of project)

Before installing all the copper grommets, I did a bit more framing. As mentioned before, if you keep thinking ahead you discover other things to do now, before the decks go on, that will make life easier later. This is a good example of that:

The plans have a King Plank spanning the aft deck. The plank adds support and provides a solid place to install a cleat. With the composite structure of the decks I probably don’t need the support there, but it does reinforce attachment of the transom, and you still need a good strong backing to mount hardware. For several reasons I would rather have two cleats off to the sides rather than one in the middle, so I split the King Plank into two separate pieces and moved them apart. Would that make these Queen Planks? Jack Planks? They’re 1/2” Ash, and will be screwed and glued. Fasteners for the cleats will get a good bite there.

 

 

 

 

 

 

 

 

 

 

The Queen Planks/Backing Blocks were a little challenging, but nothing like what came after.

The Cockpit Coamings should be installed at a slight angle of maybe 15 degrees for comfort when leaning back. But they need to be angled more at the front to merge with the centerboard case trim, matching the angle of the case. The carlins along the side already have the correct angle, so that’s no problem. The beams at the front and back, however, are plumb. They’ll need an angled shim to make a mount surface for the coamings. Sounds pretty straightforward, but these were perhaps the trickiest pieces to make so far. It took one whole day just to figure it out. Wish I’d paid more attention in Geometry class.

Here’s the rub: The decks aren’t flat – they have a crown. While laying the decks on to check fit during framing I realized this crown does all kinds of wiggie things around the cockpit. When you intersect the crown of the deck at a right angle, everything is relatively simple – the beams and coaming are straight pieces of wood cut to a simple arc. But when you slice through the crown at an angle, all of a sudden you introduce complex curves in multiple directions at once, in addition to the new angle. Wow. (Let’s see . . . the intersection of a plane with a cone at an angle is . . . an ellipse? How to you measure that? How do you cut one on a table saw?)

Not only that, but the deck itself can no longer be cut in a straight line across the boat – it, and hence the opening of the cockpit, now curves, too. If I had cut the deck flush to the beams, as intended, they would have come up 3/4” short at the front and not fit when adding the coaming later. I would have had to patch something in or revert to plumb coamings, or both. Yikes!

 

 

Rear Coaming Shim

 

 

 

 Rear Coaming Shim in place, extends the decks 3/8” at the corners.

 

 

 

Front Coaming Shim

 

 

 

 Front Coaming Shim in place, extends the decks 3/4” at the corners.

 

 

After a whole day of head scratching, pacing, pondering, I finally figured it out and got it right on the first try, but man was it tricky.

On top of everything else, while messing with decks and grommets and frames, I discovered an error made months ago. On one boat, the Sheer Clamp on one side was a tad thicker than the other. This made it stiffer, which means it did not bend to the same shape as the others. The result is one side was 1/2” flatter and more narrow near the bow than the other. I could see this clearly with the deck laid on top, which was made when the hull was still on the molds. Maybe no one else would have noticed; maybe it wouldn’t have made any difference in the way the boat pointed or tracked through the water. Would be terrible to find out later that it did. So I decided to fix it, which meant remaking three beams and adjusting others to fit. That took another day.

It was a long weekend.

 

4 Replies to “Cockpit Prep and Backing Blocks”

  1. I’m not going to be able to help myself when I see these boats. I’ll just have to say something like, what the hell took you so long to do these? All this hard work will be covered up forever, never to be seen again.
    Dave

    Thursday, July 22, 2010 – 10:07 PM

    1. Dave, if you don’t give me a hard time I’ll be very disappointed.

      Funny thing about these little boats, though, is the big cockpit means a lot of this stuff will get seen now and then. Still, I actually believed I’d be sailing three months ago. It’s clear, I have no idea what I’m talking about.

      Friday, July 23, 2010 – 01:34 PM

    1. Thomas, I had no intention of timing the debutante splash to coincide with this year’s MASCF, but at this point that is seeming a disconcerting possibility.

      Tuesday, July 27, 2010 – 11:27 PM

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