boom to mainsheet block

[lateral]

I have to shift this attachment from existing welded cleat on underside of boom
owing to new dodger.
Is a continuous loop in dyneema acceptable in the interim? (several wraps)
Race boats seem to do it.
How would you minimise chaff?
I have some 10mm SS rod and could make up a bail, but seems like a bit of a
pia fitting it to mast with compression tube, drilling, avoiding in boom lines etc.
34' boat. Keen to kis it.

[Jim Cate]

A picture of what you are replacing would help, but in general we've been using nylon webbing strops for boom attachments for years now. We use two inch "seatbelt" webbing with three wraps sewn in situ, but dyneema loops would work too. Generally a much better means of attachment than a bolted bail... spreads the load and has no stress riser hole through the boom.

Jim

[lateral]

"spreads the load and has no stress riser hole through the boom."

Thanks Jim. Validated not getting out drill & welding kit.

I like the webbing idea & should be able to get my cover guy
to stitch up. Not confident of my sewing!

[Benz]

Second what Jim said. Strops rule!

[donradcliffe]

I'm not sure how you fasten the strop to the boom to keep it from sliding in and out. All I can tell you is that in the night we needed to rig a boom preventer on a race boat, and the was nothing to tie to but the strop. We tied a bowline through the strop and let it forward to the rail. I was worried abut the strop sliding forward, but it didn't. Two hours later we were not slatting anymore and it was gusting over 30, so I removed the preventer. I was going to look to see what held the strop, but forgot until I saw this post.

[Jim Cate]

don, our strops are held in place by little sheet metal straps, around 12 mm wide and long enough to span the webbing. There is a hole drilled in each end for a securing screw, going into the boom. These hold the webbing securely. I loosen them periodically and slide the webbing around a bit in order to spread out any minor chafing that might occur.
Oh... one of these clamps on each side of the boom.

We use a strop in lieu of an outhaul car at the main's clew. That one is free to slide back and forth along the boom as the clew is tensioned or eased. Works quite well, and is one hell of a lot cheaper than good outhaul cars!

Jim

[lateral]

Thanks for the ideas guys.

[UNCIVILIZED]

Spectra strops & loops are the way to go as far as attaching things to the boom (& lots of other places). As stated, no stress risers, nor holes to drill. Plus, with them it's easy to spot wear so that you know when it's time to replace them, unlike stainless shackles & such. And they're cheap & easy to make.

Usually they stay in position fairly well, though if it's a concern, you can use an eye strap, as Jim suggests. That or loop them fully around the boom once or thrice, prior to attaching the item in question to them, so that there's more friction keeping them in position. Though pretty much regardless of how they're attached, as the load on them increases, they grip whatever they're attached to more firmly. Kind of like a prusik knot, rolling hitch, or icicle hitch.

You can use nylon in on deck applications, though it tends to be more UV sensitive than Spectra, Polyester, & some other types of cordae or webbing. And of course it's more stretchy; which can be good or bad depending on the appication.

[Delancey]

Originally Posted by lateral

I have to shift this attachment

Shift? As in move it forward or aft along the length of the boom?

[CaptJamesCook]

Originally Posted by Jim Cate

don, our strops are held in place by little sheet metal straps, around 12 mm wide and long enough to span the webbing. There is a hole drilled in each end for a securing screw, going into the boom. These hold the webbing securely. I loosen them periodically and slide the webbing around a bit in order to spread out any minor chafing that might occur.
Oh... one of these clamps on each side of the boom.

We use a strop in lieu of an outhaul car at the main's clew. That one is free to slide back and forth along the boom as the clew is tensioned or eased. Works quite well, and is one hell of a lot cheaper than good outhaul cars!

Jim

Hey Jim how about a Picture. (Of the rig I mean)
I am such a visual person.

[UNCIVILIZED]

Pick one Search results for: 'eyestrap' | APS

[lateral]

Originally Posted by Delancey

Shift? As in move it forward or aft along the length of the boom?

Aft...as the mainsheet clashes with back of a new dodger.
New mainsheet to boom angle will now be a little less than 90°.
( In amidships position)

[tstano]

Originally Posted by CaptJamesCook

Hey Jim how about a Picture. (Of the rig I mean)
I am such a visual person.

Me, too. Do you have Velcro on the three wraps? Do the eye straps come 2" wide. One picture would help.

All U Get

[Jim Cate]

Sorry guys, but it's not convenient to take and post a photo just now. But really... how hard is it to visualize a piece of s/s strap, around 1/2 mm thick (unimportant number) by 10 or 12 mm wide, and if you are using the 2 inch (50 mm) webbing that I use, about 75 mm long... long enough to extend around 12 mm from each side of the webbing. In each end is a small hole, a clearance hole for a screw (I use 10-24) that goes into tapped holes in the boom. Place strap across the webbing, put screws into holes and tighten, clamping the webbing in place. This ain't rocket science... hell, it isn't even firecracker science!

As to the velcro: I do have one such, with mating velcro on both sides of the webbing for the full length so that one could quickly install it in place without disturbing anything. I keep it for emergencies. My working strops are wrapped around the boom with adequate clearance to attach whatever hardware you wish ( perhaps 50 mm gap between boom and strop) and then hand sewn in situ, using heavy waxed twine, and going through all three layers of webbing. The exact pattern and stitch length is not important. Evans Starzinger did some tests a while back, and the outcome was that pattern was not terribly important, but number of stitches was. Mine are all different, but I put around 40-50 stitches in place. I'm kinda sloppy about stitch length, but around 4-6 mm is typical.

Hope this is enough to get you going.

Jim

[tstano]

Originally Posted by Jim Cate

This ain't rocket science... hell, it isn't even firecracker science!

Hope this is enough to get you going.

Jim

My mind is a very disturbed and creative force unfettered by common sense. NASA is still considers my thoughts to be far beyond this dimension. Anyhow, you made the retainer from stainless scrap to hold the larger strop that goes around the boom, eh? Or did you use a piece of webbing for both?

All U Get