Tuning

[Randy Church]

All,

When mast was down years back, the prebend was set before stepping the mast. Can prebend be set incorrectly and if so can that affect the mast? Does anyone in the Rhode Island area know of a rigger that is "very" familiar with tuning the B&R rig?

Thanks,
Randy

 

[Allan12210]

Prebend can affect the "fit" to the sail. The specification if memory serves me is 1% of the length of the mast. So if you pull a string between the top to the bottom of the mast there should be roughly 5 inches between the string and mast at the center. There is a lot of information on these forums on how to tune the rigging for the 34. Its really not that hard.

 

[Steve Dion]

I think that the specs are in the owners manual and you may also be ale to find the specs in the archives.

I think Allan's spec are about right.

 

[Rick486]

All,

When mast was down years back, the prebend was set before stepping the mast. Can prebend be set incorrectly and if so can that affect the mast? Does anyone in the Rhode Island area know of a rigger that is "very" familiar with tuning the B&R rig?

Thanks,
Randy

Try Fleet Yacht Sales in Bristol. Ask for Matt.

 

[Randy Church]

Try Fleet Yacht Sales in Bristol. Ask for Matt.

The rig was inspected and tuned by rigger back in 2010. When it came out of the water in 2012 and was on stands it looked to me that the mast was leaning to starboard. New person on boat this year did quick halyard measurement and it appeared to be 1.5 difference. We spent a few hours yesterday attempting to straighten after reading Hunter B&R tuning directions and "no joy". When we put the corrective tensions/backing off on forward shrouds, after loosening backstay and other shrouds, we had a diagonal go completely slack. We're thinking the pre-bend was set incorrectly by yard personnel unfamiliar with the rig last time it was stepped (2009). Pre-bend is definitely somewhere between 5-8 inches after we did the main halyard test yesterday.

 

[VINN]

my yard use to take the rig down every winter to store it on the other side of the street, and every summer it had different mediocre rig tuning until i became involved. one test i used was to pull on the cap shroud to observe if the upper diag went slack on each side. if it did thats wrong and i fixed it by pre tensioning the 2 turnbuckles above the lower spreader. the other lower turnbuckles near the base of the mast should be pre tensioned equally to give the mast a nice curve to match the top of the mast and fit the main sail luft correctly. then you can pre tension the turnbuckles on the inside of the chain plates to hold that curve from moving foward. the intermediate shrouds and cap shrouds will put presure on the spreaders to hold the shape too and should be pre tensioned equally on both sides to keep the mast straight. hoist a tape measure lead to the top of the mast and measure to each chain plate and they should be exactly the same. this is usually the first thing i do when stepping my mast. all thats left is applying your back stay average tension for say a 10 knot day. one of a few more tips is never ck and believe the mast is off or straight by just looking at it. depending on if the mast is front lighted ar backlit it can look entirely different from one side or another and you can end up chasing your tail for hours or even days. use measurements using a non stretch fiberglass tape measure you can get down to a cm or even a mm... then you will be able to find that extra 1/2 of a knot. i hope this info helps other h34 owners back into the limelight.