Rigging Hunter 340

Dan Johnson · Dec 18, 2011

Lahna...

My '83 H34 has a B&R rig similar to that used on your boat. Mine is a mast-head rig. It does not have as much of an aft rake to the mast set.

While yours seems to have a bit more aftward bend in the mast than mine, it doesn't look out of place when compared with other fractional rigged boats I have seen that are set up for competition and don't have a backstay rigged.

Allan12210 · Dec 18, 2011

Looks typical for a B and R rig. They are different from a conventional rig. The pre-bend or bow in the mast is achieved by tensioning the diamond stays even before the mast is stepped onto the boat. It is supposed to be 1% of the mast length. So for a 50 foot mast, the diamonds are tightened equally until a string pulled from the top to the bottom is 0.5 feet or 6 inches away from the middle of the mast where it is bulging. The sail will have been cut to match that curvature. After the mast is up, then the rake or tilt away from vertical can be adjusted with the forestay and the shrouds that are off the spreaders behind the mast. This will determine sailing performance, especially weather helm. Too far forward will create a lot of weather helm. The proper rake on my H34 is just a few inches aft.

Enjoy your boat.

Allan

kloudie1 · Dec 19, 2011

Minor note: the 1% number is on the mast height above the boom .. which is the "P" dimension for a boat.. Note that this is from the original owner's manual for the "old" 34's like mine.. Don't know if the set-up is the same for the rig of the newer 34's that have no backstay.

John T1594 · Dec 19, 2011

Looks OK - but measure it

I have the same boat, same year, same mast. The aft rake to your mast looks about right.
According to the owner's manual: "the mast bend is induced by tightening the reverse diagonals (diamonds). Measure the bend by lowering the main halyard from the masthead to the gooseneck. The maximum amount of bend should be no more that 8" (203mm) for the standard rig and no more than 2" (50mm) for the furling rig."

Allan12210 · Dec 19, 2011

John T1594 said:
The maximum amount of bend should be no more that 8" (203mm) for the standard rig and no more than 2" (50mm) for the furling rig."

I would assume the furling rig refers to a furling mainsail and not a furling jib.

Barnacle Bill · Dec 19, 2011

I assume the mast section was built by Selden and they have a tuning guide which is quite good and the B&R rig is included. If you give me an address, I can send you one, or you can contact Selden and they will send you one. I have them in stock (for free).

steve stark · Dec 19, 2011

Lahna,
As another point of reference, we have a 2001 340 and our mast looks to have about the same amount of pre-bend as yours. I have often worried over how much pre-bend it exhibits, but other boats in our area seem to be about the same. I have never measured it, but it appears to estimate out at about 6 to 8 inches.

As a matter of interest, the bend you have pictured is not "rake". Rake is the degree of 'lean' off of vertical for the entire (or average) of the mast section.

When we had our boat commissioned three years ago after shipping, the rigger put the maximum amount of bend in to stretch a couple of more years out of the 8 year old sails and allow maximum flatness for higher winds. When we have a new sail cut next year, we will stick with the current bend and have the cut made to match, as that appears to be the original intent between Hunter and Doyle.

-Steve

harv · Dec 19, 2011

HI,
My son has a Hunter 310 with the B&R rig (no Backstays). I spent a lot of time researching the problem of tuning. I even talked to Brian Toss, one of the US experts in rigging.
A summary of tuning the rig would be to loosen the rig somewhat, adjust the rake, then put in the mast bend, and adjust the lowers and forestay, which adjusts the rake (again) and the forestay tension.
With the lowers lossened and the forestay lossened and the mast bend put into the mast with the diamonds, the mast bend will now be along the whole lenght of the mast. The key to tuning is to tighten the lowers to bring the lower part of the mast back more in line and which will put more of the bend into the upper part of the mast. Your mast bend will look more like it is on a regular rig, with more of the bend being above the spreaders.
Adjusting the uppers and the forestay (if it can be adjusted) will affect the mast bend above the spreaders and the forestay tension. Then use the Loos gauge rig recomendations on rig tension.
The best solution is to give Hunter a call and ask them to send you the manual pages on the rig picture descriptions and the one or two page outline on tuning the rig. It dosen't even have to be on a H340. Any similar model from the 1998 models on will do.

Rigging Hunter 340

.

Attachments

.

.

.

.

.

.

.

.

.

.

.