Join Date: Nov 2006
Location: Beacon, New York
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Originally Posted by SVArgo
I believe that it is still LaFiell mast, not 100% though, I'll know about 0930 tomorrow. I actually tried to do a quick calculation based on LaFiell's information in the link you sent, but they didn't give the units on the moment of inertia, so I'm not quite sure if its coming out right. I've got some mast section data at work that I'll check tomorrow and see if I can't figure out how much tension would be required for a couple inches of rake.
At any rate, the one I believe the boat is fitted with is the OM3D, very beefy as you note. Definitely not a floppy racing rig!
I believe the moment of inertia Lefiell quotes is in inches to the fourth power. That also matches what I have for some other similar sections. And just a side trip into terminology. I think rake refers to the amount the mast tilts so a 3” rake would mean the masthead is 4” aft of the step. That rake would be the same if the mast had a bow in it or not. It just refers to how far the masthead is displaced compared to the heel or step. I think your rig does have some small amount of rake, 2 or 3 inches, but again it’s not a bendy rig and it needs to be straight between the step and masthead.
All the best,
PS. Lots of Yacht Clubs and small yards will step a mast but don’t have the expertise to tune or service one. They will step a mast that has obvious defects without even seeing them. Even in a “good” yard the owner should at least check the mast before steeping and if possible be there to be sure everything goes well. And it goes without saying you need to be aware of your masts condition and how the rig is tuned at all times. Its makes for a bad day if you drop the rig even if you are in sight of home and offshore it may become life threatening.
Study the history of naval architecture and move forward knowing what didnít work before.
Donít waste time making the same old mistakes but instead make new ones and to insure your place in history be sure the mistakes are big ones.
Never design a mast that is weaker then the boat
Never design a boat that is weaker then the mast
Never listen to someone describe why your project will not work unless they can show you the broken pieces of their own version.
Last edited by Tartan34C; 10-16-2007 at 06:33 AM.