H31 Backstay Adjuster

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Jun 5, 2004
35
Hunter 31_83-87 San Francisco
Has anyone tried to put a multi-part backstay adjuster on a H31? The mast already has a fair amount of pre-bend in it, but there are times I'd like the option to bend the mast. I have a split backstay, so there are systems that will fit the bill, but I'm not sure they'll actually do anything useful with the B&R rig. I question this because later versions of the Hunter eliminate the backstay altogether, and that last time I had the mast pulled, the riggers said the backstay was redundant. So how do you get dynamic mast adjustment on a B&R rig? -Richard S/V Discovery SF
 
D

Doug Washburn

I have been told...

...that adjusting the back stay on a 31 is redundant. The pre-bend built into the B&R rig is intended to produce the optimal main shape. Also, I would be chary about putting any additional downward pressure on the mast in deference to the 31's inherant mast step compression problem.
 
Jan 7, 2004
43
Hunter 31 Kingsville, Ontario, Canada
Backstay Adjuster

I have the spilt backstay as well (with adjuster) and I find it does help when going up wind to put extra pressure on the backstay. The mast has a lot of prebend built in (mine is at 4.5") but I can get the mast back another few inches (I've checked it by hanging a plumb bob from the main halyard and then tensioning the backstay and measuring the difference)it does straighten out the forestay sag and gives the genoa a better shape - especially in upwind slop. Now to make a difference I have an 8:1 split tackle on mine with which I can put a lot of tension in the rig. My mast step is solid and my rig is tuned as per B & R instructions. The later model B & R Hunter rigs where a somewhat different setup (outer shrouds attached at the outside of the hull, fractional rig, etc., which sets up a whole different level of geometry in the rig requirements) and to say the backstay on this model of Hunter (masthead rig, narrower sheeting angles, bigger head sails, etc.) is redundent is non sense - ask these guys who say it's redundent if they would remove the backstay AND then go out and sail? I can garantee they probably wouldn't! If you race the boat put an adjustable backstay setup on, even if it doesen't make a huge difference it will make you feel like you've done something, if you cruise don't spend the money. Mike
 
Jun 4, 2004
4
- - Erie PA
Backstay adjuster

I do club JAM racing in my H31 and added a backstay adjuster this season. It makes a tremendous difference in pointing angle and speed in heavy air. I bought the whole set-up with a four-part tackle from Garhauer, and it took me about ten minutes to install it. I highly recommend it if you're racing. Tom Madura s/v Good Vices
 
M

Marc

Back stay adjuster

While a back stay adjuster will give you all the benefits stated in the previous responses, it has a large draw back. IT WILL SERIOUSLY WEAKEN THE MAST. The B&R rig is designed as a composite strucural unit. The diamond rigging pattern that provides the mast prebend also acts as a structural member that provides stiffness while allowing a smaller mast cross section and lighter weight aloft. The use of a back stay adjuster bends the mast and loosens the diamond rigging as well as the shrouds and puts the integrity of the rig at risk.
 
Jan 7, 2004
43
Hunter 31 Kingsville, Ontario, Canada
More Backstay Adjuster....

while I have to admit that Marc may have a valid point, the outer shrouds can loosen apprecaibely when you really reef on the backstay the diamonds do not seem to loosen appreciabely. Using a Loos tension gauge the difference when the adjuster is pulled up tight and loose is marginal. The outers of course can be loosened considerably when major tension is applied. As for weakening the rig - I find that doubtful, you are benidng the mast in a fore and aft plane, the standing rigging is still supporting the mast side to side so I can't see where it would weaken it. It is a flexible spar for a reason. I may not be correct on this but I will happily trade off up wind performance for what I see as a very minor risk. I check my rig very carefully every year when it is taken down (on past boats I have always dropped the rig for winter storage, as this is the first year for me with this particular boat I will continue this practice)and have always replaced anything that is questionable so I don't anticipate a problem. Thanks Mike
 
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