Friday, April 23, 2010

Daggerboard case intallation, spars

WELL I'm on a schedule where I'm home about 48 hrs a week, which means 47 hrs of boatbuilding, and 1 hour of laundry.  Not really.

So during my past 48 hrs home I got to it and was able to install the daggerboard case and I hit on a major find for my spars.

For starters, I dragged my boat out of the garage into the driveway and noticed a pronounced twist in the stern.  If the intrepid reader remembers, I glued down my rear seat last time, and gluing down the rear seat definitely locks in and twist into the hull.  Because of this I was super super careful to make sure there was no twist when I glued it in, using a level and some strategically placed buckets.  I ran outside and moved my boat... and the twist was still there.  There was no way I was going to get any work done if the boat was twisted.  Using some brute force and a rigid vacuum tube I rolled my boat to the pond and threw it in the water.... and she floated straight as a die.  No twist.  PHEW!!!  HOLY HOT HEART ATTACK BATMAN!

Back out of the water, I did some sanding in the interior of the hull to make it easier in the future, and went around installing the daggerboard case.  What is most important is that the case is straight.  If it comes off-kilter, I've got a giant blade dragging me off into some obscure direction that I'm going to counteract with the rudder, and it's going to be drag city.  In order to make sure that the case is straight, I stretched a string from the center of BH2 to BH3 over the top of the case.

So here it is, mocked into position with my centerline string.  I tried at first to do this on the ground, but I got much better results up on the buckets.  I think the runners are slightly different and offering tweaked ground handling characteristics.

I cut the ribs for the front of the seat amidships.  They actually came out ever-so-slightly larger than needed- a mistake- that ended up helping me out in the end.  When I put the case into position it would slip around with the oversized rib, I could gently cajole the case into position which was verified by the string.  When everything was straight, I carefully clamped everything into position.  You'll notice the square behind the ribs next to the case to increase gluing area.  The port rib is a little higher than it should be (remember, they were a tad oversize) and I'll plane it down level for the seat installation.

This whole skeleton will be glued together by the center seat.  This, with BH3 and the forward ribs will create the lever that will hold the case in place.  Remember, when I capsize, I'm going to be standing on the daggerboard to right the boat, with all my pressure on the case.  This massive gluing area will keep it from ripping out when I'm in the water in the middle of nowhere.

Here are two shots of my daggerboard case lined up with my string.

In other news, I went over to Goose Bay Lumber to grab some Doug Fir 1x4's so I could glue up some spars.  I had come up with some crazy idea to put the spars together as a laminated structure since I didn't think I'd find blanks that were large enough.  I did.  I found some finished 2x6 DF boards that were 20 feet long.  I had them cut to 12 feet.  A quick rip on my table saw, and I had two skinny blanks and one fat blank.

The spars are on average 40mm diameter.  I get 37mm with the blanks.  My spar is about 37mm x 40 mm or so.  I'll keep it like this for the length and not taper it.  It's kind of bendy, and I need some bendy up at the top of my sail, since I hear that the Duckworks sail can be a little flat.  This should help.  My boom will be 37mm x 50mm or so.  If these are too bendy, I can laminate some ply at key areas to stiffen it up.  This was a quick, easy, and totally suitable solution.  Easy!

Until next week, intrepid reader!


  1. Nice progress. You are right to take the time to get the center case lined up true! Living with two rudders would be like having two wives :)

    By the way, if the DW sail is flat at the top, you are going to need a stiff yard, not a bendy one. There are many sail makers who say the lug rig works best with a stiff yard, as you already have a fair bit of flex from the attachment point of the halyard. Anyway, yards and booms are quick and easy to make, so wait and see what your sail is like first :)

  2. I thought I read in the GIS Spar thread ( over at Storer Forum that bendy was better for the spar. Maybe I should sit down again and read it more closely.