37C Running backstay pics

[pbknowles]

Hi, can any other 37C owners post up some pics of the deck end of your running backstays? Mine were missing when I bought my boat. The tangs are there on the mast but nothing else. Interested in what the tackle should look like.
TIA!

 

[DianaOfBurlington]

From the tangs should descend good (new) 1x19 SS rigging cable, about 7/32" or 1/4" (or about 80 percent the diameter of the boat's current and correct standing rigging). These cables should never be longer than to enable the whole thing, including the rope tackle with its end clipped to the mast base, to lie straight down and snug along the side of the mast. The lower terminal fitting should be an aircraft eye with like a 7/16" or 1/2" pin. Other 37C owners will weigh in here; go with what the best of them have.

On my little boat I left the wire about 21" short of the deck, which permits the inner forestay and the running backs to be stored against the mast; but they do bang it there in good wind and make an ugly noise; so they're better stored off to the rail, behind the aft lower shrouds (not against the shrouds; that's just another ugly noise). Call this your 'at-rest' position. Measure your own rope tackle assembly to be sure BEFORE you cut the wire and send it off to be machine-swaged. (I made this mistake with mine already.)

On that boat the tackle should be AT LEAST 4:1 (two fiddle blocks, preferably akin to Schaefer 7-series) with like 1/2" line, with the snap shackle at the BOTTOM (block to deck), to attach to and move from the deck. There is NO reason to have a snap shackle at the top (block to wire) - in other words, this is not really vang tackle (which would have two snap shackles to make whole thing removable). Technically the running backs' (rope) tackle is part of the standing rigging and never leaves the boat. That's why you have an 'at-rest' position along the shrouds.

Get the rope portions professionally spliced to the lower blocks (given 4:1, the bottom one has the becket). You'll find it's awkward to adapt the blocks to the upside-down shackle (clevis-side-up) dangling from the wire without resorting to using two shackles together. I found some perfect 1980s-vintage Nicro blocks with the 'upset shackle' for my 1974 timepiece; but you can just hook the blocks' own shackles (which should swivel at this end) to the shackles on the wires. Use quality polished-SS clevis pins and NEW cotter pins.

In some applications having the cam cleat on the lower block makes sense; in other applications it's better to lead the line off the bottom fiddle block (which would then have no cam cleat) and tail it somewhere else. I'd say your boat, based on size, is about on the borderline between the two. I currently have a fiddle block with cam cleat at the bottom of my backstay adjuster (nice SS blocks that actually came from my dad's own H25 from 1974; so there's karma in them) but I am seriously thinking of leading it forward along the side of the cockpit since it's easier to reach it there. The running-back tackle is not much different; but tailing it anywhere except on the (movable) bottom block means you'll have to allow for varying positions at the deck, like a genoa-sheet lead block (to which it is VERY similar); so maybe it's best just to have good, big blocks with their own cam cleats.

Coil the excess line and dangle it from the lifelines. It's okay; this is considered yachtlike and shipshape; and above all you must make sure that the line's own weight dangling from the cam cleat can't dislodge it while under way.

I made moveable tackle for Diana using standard, non-swivel blocks and adding standard tack-type (with clevis) snap shackles. They fit equivalently-sized blocks; but mind the load ratings of each piece. NEVER attach other shackles or hardware to the bail of a snap shackle; that's meant for rope splices only.

Running backs are 'standing rigging' - definitely meant for proper clevis pins and cotter pins (not roll pins). Avoid ALL bolt-pin shackles (unless you're using threadlocker; and keep them accessible anyway) and all key-pin shackles for standing rigging, including the wire ends of your running backs. If you're using screw pins, wire them securely (that's what the hole in the screw pin is for) with SS seizing wire.

The deck should be fitted with AT LEAST TWO separate pairs of attachment points, one point at the 'at-rest' position (close behind the aft lower shrouds but without letting them bang the shrouds) and one point that corresponds with the inner forestay, at about the same angle down from the mast. Measure the distance from the front face of the mast to the inner forestay at the deck - this is known as the 'J2' (the second 'J' measurement) and so the running backs should be able to be set at about the same distance from the aft face of the mast, measured along the centerline. (This location is probably already evident on your boat.) Too close and it's under too much load; too far aft and it's got diminishing returns through about 45 degrees. Past 45 degrees there is no point.

The working attachment point should use good SS U-bolts (about 5/16" dia. at minimum; see Wichard). Think about 2500 lbs SWL. These MUST have very good backing plates under the rail, ideally aluminum angle at least 1/8" thick, and encompassing like 2 or 3 of the toerail's boltholes in either direction.

Yes; it'll look like the boom will foul them when they're attached at the after point. But the leeward runner is meant to be eased when you're on the wind (also it's for safety, to let the main boom all the way out in case you can't head up). 'Playing' the running backs is a part of the game with this rig. Remember that this is how all those Alden schooners kept from losing the mast when they jibed - unlike 7 out of 9 of the Cherubini 48 schooners whose buyers didn't trust my dad's design, they had NO standing backstays (same as a true Bergstrom rig, which a C48 is supposed to have). Again - it's part of the game. Smart is as smart does.

BTW - when you step the mast, attach the inner forestay to the deck and rig the runners to their aft positions ASAP. Then you can effectively get rid of the $450/hr crane guy and take your time calmly attaching everything else. Outer forestay goes on last (NOT first!).

My long-standing recommendation is to get rid of the 'self-tending' staysail boom and have a second headsail furler there with about a 125% jib with a raised clew (for visibility) on it. This requires a little more work when trimming sail; but it makes a very efficient rig especially for hard tacking and heavier weather; and it frees up your foredeck considerably. I eliminated the staysail boom for the last two production C44s and they're both better (and faster) for it.

In effect you end up with the inner forestay and the running backs as a separate, self-contained rig. Fly your double-reefed main and inner jib alone as a reduced sloop rig, and you see the benefit of having a cutter to begin with.

 

[Mikem]

Hi, can any other 37C owners post up some pics of the deck end of your running backstays? Mine were missing when I bought my boat. The tangs are there on the mast but nothing else. Interested in what the tackle should look like.
TIA!

Will these pics help. From my daughter’s 1984 H37C, “Harmonic “

 

[pbknowles]

Thank you both for the replies! Extremely helpful. Based on DoB's detailed description and the pics some of the tackle may actually be on the boat after all, just stashed in a junk drawer. I hope to find the backing plates/evidence for botht he "at rest" position and the working position by studying the toerail. Since it will be few years until she goes back in the water I have saved DoB's treatise separately as well so I don't lose it!