Wednesday, March 04, 2015

Dawn Patrol gets a new Depth Indicator

Also known as a centerboard. This year we finally got around to switching over to a weighted centerboard. 31lbs all up including the lead in the tip. The uphaul line is a 10:1 cascaded purchase and the top of the trunk is now covered in a 6mm piece of lexan. There is a small block that angles the uphaul out of the side of the board and back into the cockpit. This is sealed with a plywood box and lexan cover and a pvc pipe to lead the line aft.

The biggest advantage of this system over the old is that at high speeds (10 knots plus) water would siphon up the trunk and spill out sometimes forcefully like a geyser into the cockpit and the cabin. On several occasions this was a rude awakening to the poor sucker trying to sleep in the cabin. The only solution was to stuff sponges into the top of the trunk which kind of works but eventually they are ejected and they hinder movement of the board. Here are some pictures of the new setup.

A typical example of speeds where water gushes up through the centerboard trunk
Taken during the NCPC 2014. Sailing with reefed mizzen only. 

Custom lead tip cast at the shop at B&B

First side of CB glassed up (inside due to the cold)

View down in the trunk before the lexan went down. 

Box and pvc pipe seals the exit block and line leading aft.

All finished with lexan top screwed down and small 
filler piece to fill the gap in the door frame. 

10:1 purchase. 20lbs of pull required to raise the board fully horizontal. 


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