Regarding the Backstay tensioner on SUNDOG:

The parts consist of:
1. About 25 feet of 5/16" braided line (Sta-Set)
2. Two Wichard twisted captive pin shackles (3/16") pin size
3. Triangle plates 3/8" Schaffer part # 285728 (they come in pairs with 3 clevis pins and cotters.)
4. Two Ronstan wire blocks #RF 104 AW.
5. One Schaefer Sheeve # 6202315BW
6. Ronstan Bullseye fairlead and cam cleat on swivel base #RF67
7. 15 or 20 stainless flat washers with 3/8" holes.
8. Two lengths of 7/32" vinyl coated lifeline wire and two adjusting barrel style turnbuckles.
9. 1 Ronstan block RF1711

Proceedure:
Slack the backstays enough to remove each one (ONE AT A TIME) and shift the turnbuckle bases to the inboard hole in the chain plate. The backstay will end up inboard the pushpit railings (probably touching them). Re-tighten to approx. factory values.

Measure distance between backstays at contact point of each backstay on pushpit railing...subtract four inches from that measurement.

Go to West Marine store or any rigger who can do life line swaging and has fittings. Fabricate the two lifeline "legs" that will attach to the two upper clevis pins in the triangle plate via a turnbuckle on each leg and on the other ends, do a thinble connection to the wire blocks that will ride on the backstay. The overall "spread" of this assembly is to be the measurement you did earlier with the turnbuckles set in the middle of their adjustment range.

While you at the rigger, do a tight "eye" splice in one end of the Sta-Set braided line. Put one of the twisted shackles on this eye.

Assemble the triangle plate with the line sheeve in the lower position on the plate. The two upper positions will be for the turnbuckle ends...use the ss washers on the inside of the plates to make a snug (but not too tight) assembly when the plates are pinned together with the 3/8" clevis pins. The sheeve will rotate on the lower clevis pin as it's axle. You may need to make sure the clevis pins that come with the plate are long enough to accomodate the lower sheeve between them...if not, just buy 3 longer 3/8" clevis pins and use the washers to make up a snug assembly.

Take the axles out of the wire blocks and attach the center assembly to the backstays by putting each wire block onto each backstay. Be careful not to drop pins, sheeves etc. overboard....helps to have another pair of hands to do this!!

Attach the eye splice shackle on the outboard hole of either chain plate and feed line up and through sheeve in triangle plate. Attach block via remaining twisted shackle to the other open hole in the opposite chain plate and feed bitter end of control line through it and then back up to just inside pushpit base, where you will mount the bullseye cam cleat to the deck just adjacent to the inboard side of the inboard pushpit base plate...or wherever you wish to put it, so that's it's handy and has a fair lead to the block on the chainplate.

Now, you need to use a LOOS gauge to finsh tuning the rig using the stock lower turnbuckles and the adjustment provided by the two turnbuckles on the tensioner "legs". When the tension rig is "slack" the backstays should carry about 400-425 pounds on each one. Make them as even as you can. When you pull the tension line as hard as you comfortably can by hand, you will end up with about 500-550 on each backstay. I would not exceed about 1200 pounds on the forestay (600 on each backstay leg) and you can get that much just by starting a little higher up with your pinch rig than the top of the pushpit railings...but don't overdo it. You just want a little edge to get some of the sag out of the forestay so you can point higher, but it will always have some. Slack the tension off on a reach or a run and ALWAYS leave it slack when you are not using the boat. When daysailing, we just apply a little tension to keep the rig snug....and slack it off when we put the boat away or when we anchor for the night.

Rob Hoffman SUNDOG #551

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