Self tending head sail height.

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norfolk
Posts: 3
Joined: Sun Jan 18, 2009 7:14 pm

Self tending head sail height.

Post by norfolk »

It seems that if you took the head sail to the mast head on the Mull designed 36/38 you would increase the sail size by about 50%.

What do you think would be the result on the stability of the mast? Does the forestay really offer support, or is it there for the rigging of the jib only? Would mast be compromised taking the load to the masthead?

dwight
Posts: 68
Joined: Sun Dec 07, 2008 3:41 pm
Location: Newport, RI
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Re: Self tending head sail height.

Post by dwight »

As I understand the sequence of events, the F32 (or F30, I forget which) was designed immediately before the F36 and had a 3/4 height headstay. I have been told that several masts broke due to the whipping effect of the unstayed mast being checked by the headstay. This applied an impact load to the hounds that lead to the failures. To prevent this TPI designed the F36 with a 1/2 height headstay. They really wanted a catboat, but Gary Hoyt convinced them that a jib was needed. Remember that this was early in the development of carbon fiber masts as well as unstayed masts.

Now days you can build a mast with half the weight and design-in enough strength to withstand these loads, but at a hefty price. I often wish that I could afford to buy a new mast with a 3/4 height headstay. I have considered building a stainless steel bowsprit to move the headstay forward a couple of feet. While less than a new mast, still expensive.

For now, I have a halyard on the front of the masthead and use an F45 drifiter in light air and try to be sensitive to the loads this is applying to the mast.
Dwight Escalera
Accredited Marine Surveyor, SAMS #1024
former engineer at Freedom Yachts
former owner F36-71
Wakefield, RI

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