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Mast steps

Posted 6 months, 20 days ago

Mast steps
The where, when, why of deck stepped versus keel stepped:From Paul France - NZCan anyone explain clearly why we carry masts down through the cabin to the keel. I look at my 1970 IOR One-Tonner and don't understand it. To my mind for that boat, the shorter the length of alloy extrusion you have to keep in column the better, but there's this mast going all the way down to the keel. So why don't we step the mast on the deck and have a strut below?From Scuttlebutt:While we weren't there that day when they decided that keel-stepped was a better idea, we believe that the issues mostly have to do with deck compression. There is a lot of load on the rigs, and rather than dealing with the structure needed to keep the decks from sagging (and thus loosening rig tension), the simpler solution was to run the mast down to the bottom. Also, there are boats that have hydraulic rams at the butt to tighten the rig by raising the mast up. Other advantages have to do with mast bend, as you can either induce bend or restrict it by either moving the mast butt fore and after or by adjusting the mast chalks. We suspect the mast butt is also better mounted down low with only vertical loading rather than at the deck with more varied loading demands.From Paul France - NZ:Thanks for that. I'll try to locate someone who was there on that day, or maybe a designer/engineer. If I get a better answer, I'll let you know. Cheers and be assured I get a lot of pleasure out of ScuttlebuttAdditional thoughts? Post them in the comments section. Full Story »

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