MAST PREBEND

[KEITH NELSON]

DOES ANYONE KNOW HOW MANY INCHES OF PREBEND THE MAST SHOULD HAVE WITHOUT ANY LOAD. ALSO WHERE IS THE ZINC IN MY HEAT EXCHANGER ON MY 3CYL. YANMAR.

 

[Rod Leonard]

Pre bend

The numbers I was given was 2% of the mast hight. I use to set up my 31 with 5" seemed to be the best set up for it.

 

[Pete]

zincs

3 cyl yanmar,if fresh water, cooled has no zincs

 

[Ron Barrow]

It depends....

Kieth:Last year my rig was set with about 8" of prebend. More mast bend will help to flatten a sail that has too much fullness. Flatter sails are desirable in heavy air. In more moderate conditions, more draft might be desired. When racing, you might want to adjust your rig depending on the conditions. The standard 33.5 is not that easy to adjust on a daily basis; so, I would guess that most of us who race the boat try to find an acceptable compromise. Do you have a back stay adjuster? The rig is so easy to bend that I use a small unit on the split backstays. The unit was easy to install and not expensive. Good Luck, Ron

 

[Doug B.]

What Hunter says vs. what riggers say

On our 33.5 I called Hunter (greg emerson)in Alachua, FL before hiring a tuner. I did this to address that very question (as I see all sorts of differences at the marina on Hunters) and also to get a referal to a qualified Hunter commisioner. I did get the person they recommend for the whole state of Washington even though their yard no longer sells the Hunter line. Hunter told me 3" of prebend with the split backstay adjuster all the way up. The rigger recommended about 5. Looks can be decieving. Try letting your main halyard shackle dangle an inch off the boom on a super calm day to get a good idea. We went with about 5-6 on the last tune. We find this to be a good split for getting enough draft on calm days and a flat enough sail on gusty days and for pointing high. Good luck.Doug