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Mast Rake ?

PostPosted: Tue Jul 31, 2007 9:44 am
by Kevin F
After about a year of "work" I am finally ready to splash my DS1. I fully rigged it in the back yard to get the process down before the "day at the ramp" and the ten thousand or so on lookers who always seem to show up. What I found, and is the source of my question, is the mast seems to have alot of rake. Considering the the mast step and "whole in the deck" are realitively fixed I would think the rake would not be very adjustable. What is normal for the DS1?

PostPosted: Tue Jul 31, 2007 9:52 am
by jpclowes
North Sails has a good tuning guide online. It is kind of hard to find, but is really helpful. If you go to their "One Design" section, then search around, you will find a list of tuning guides for several different classes. Ours is one of them. This gives you measurements from the top of the mast to the Stern Deck, hull joint, which should give you the proper mast rake.

tuning guide link

PostPosted: Tue Jul 31, 2007 6:14 pm
by Roger
Here is the link to the tuning guide for the daysailer.

http://www.northsailsod.com/class/daysa ... uning.html

PostPosted: Tue Jul 31, 2007 11:26 pm
by Phill
Mast rake numbers for the DS can be misleading. Many of us have hulls with the mast step and mast deck hole that are not all in the same place. That can make a particular measurement perfect if you have a hull with the same step and hole, but you can be off if you dont. To make the situation even more confusing, many of us have masts that are shorter and are not the full 24" between the deck and goosneck. (mine is 21"). So a measurement from my mast maybe as much as 2-4" off from what would be best for your boat.

Please dont think that the racers in our class are 'guarding secrets'. We want to help all enjoy thier boats. Its just that with all the variables a "one size fits all" measurement could be very wrong for your boat.

For mast rake, sail the upwind in 7-9 mph wind, with the centerboard completely down. When the boat is very close to FLAT, no heel, you should feel a very very slight pressure from the tiller trying to turn the boat toward the wind. (weather helm). If there is more than a very slight tendancy to turn, you will need less mast rake aft. Lengthen shroulds and shorten forestay. If there is no tendancy to turn up or a turn to leeward, away from the wind, you will need more rake, longer forestay, shorter shroulds. Make these changes a little at a time and you will get it dialed in and have a perfectly balanced DS for most conditions.

Kevin, if when you first launch, and find that there may be too much weather helm, try pulling the Centerboard up 3-8". That should reduce the weather helm until you can adjust the mast step and shrouds/forestay to permenantly get the rake set.

hope this helps.

phill