Chain Stopper Installation Questions

[bytownboy]

I am installing a chain stopper made by Anchorlift - a nice skookum looking piece of gear. I need to raise it about 3/4" off deck to have chain flow smoothly and not pull up on stopper when chain tight. As per pictures I plan to put a block of wood under stopper. Will bolt through wood, through stopper, deck and backing plate.

Should I also drill a set of four separate holes through wood and bolt it down to deck and backer plate, or is this overkill?

I am using oak as that is the most suitable wood I have handy - is there a better material to use that is fairly easy to obtain (small town Vancouver Island but Home Depot not too far away)?

[mrm]

Originally Posted by bytownboy

I am using oak as that is the most suitable wood I have handy - is there a better material to use that is fairly easy to obtain (small town Vancouver Island but Home Depot not too far away)?

How about replacing that wood with a block of G10 / FR-4 laminate? Good for a backing plate too.

[Red Sky]

As you're only using the wood as a shim, no need to attach it separately. Because you are through-bolting the fitting, the load is imparted to the backing plate.

[bytownboy]

Thanks mrm and Red Sky. I will proceed with the painted oak as pictured unless I can find a small piece of G10.

Doug

[stillbuilding]

Lewmar and Maxwell both make a stopper which is elevated off the deck. Expensive though.




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[Red Sky]

A piece of Starboard would work also and be moisture/rot proof with no maintenance needed.

[Stumble]

Originally Posted by Red Sky

A piece of Starboard would work also and be moisture/rot proof with no maintenance needed.

Starboard is not suitable for any load bearing application. G10 however is ideal, far better than wood since it won't rot.

[thinwater]

Originally Posted by Stumble

Starboard is not suitable for any load bearing application. G10 however is ideal, far better than wood since it won't rot.

The thing I like about GRP for this application is that I can bond it to the deck. The load is only partially, in tension; it is also in sheer, and a bonded shim will be MUCH better at resisting shear without shifting, particularly if the deck is cored. With the wood there will be little support for the thickness of the shim + core.

A GRP pad would also reduce the backing plate thickness requirement.

I would bond GRP and then drill through AFTER it cured. Perfect fit. Doesn't need to be G10; any structural grade will do fine in sheer. Of course, this is harder to do neatly.

In truth, this only matters if you do not use a snubber, or use a very short one. My chain stopper is only used to secure the anchor on-deck and as a snubber back-up.

[Red Sky]

Originally Posted by thinwater

In truth, this only matters if you do not use a snubber, or use a very short one. My chain stopper is only used to secure the anchor on-deck and as a snubber back-up.

Exactly why I recommended Starboard.

[UNCIVILIZED]

You can lay up a custom thickness of GRP on any work bench. And if you want to approach G10's properties, do it under vacuum, & then post cure things (with the right resin).
Or epoxy bond together a bunch of scraps of 3mm marine ply. They're thin enough that the resin should fully penetrate/permeate each layer, even without a vacuum being applied.

Albeit the one nice thing about G10, is that you can tap it for fasteners. So that in addition to bonding it to the boat, to spread the load that way. It becomes an integral part of your stopper setup, when used as "nuts", on the backing plate side.
Though a metal backer, or washers, & stainless nuts would still be advised in this application. Given the loads that it'll see on occasion, when transitioning to or from a snubber.

That said, if it's not readily available, aluminum would likely work out better than oak. Too, you might also look for a piece of marine lumber. Something which is naturally oily, & rot resistant.
You'll find some scraps of that, anywhere there are boats, even if it takes 5min. of dumpster diving, or asking your neighbors.
That, or even a piece of MDO, which is pretty much impervious to water, as compared to a lot of regular hardwoods. Oak included.

[UNCIVILIZED]

Originally Posted by Red Sky

A piece of Starboard would work also and be moisture/rot proof with no maintenance needed.

How well will the Starboard hold up from the time when the chain stopper is applied, until the snubber is hooked up? Or when the snubber breaks, or reaches it's limit, etc.?
Is it up for those kinds of loadings? I don't have it's spec's handy.

[01kiwijohn]

Just use the four bolt holes that are there, but use bolts long enough to go through the stopper, deck and block and the backing plate underneath.
Don't forget to add a little medium strength Loctite, or nyloc nuts.

[deblen]

Originally Posted by 01kiwijohn

Just use the four bolt holes that are there, but use bolts long enough to go through the stopper, deck and block and the backing plate underneath.
Don't forget to add a little medium strength Loctite, or nyloc nuts.

Always use nyloc nuts &/or locktite on SS bolts if possible. SS doesn't stretch like steel & regular nuts can vibrate loose.
That oak will probably last you out,but if you know of a salmon cage mfgr. outfit near you,get a square of HDPE from them. Lasts forever & also great for backing plates also.

Cheers/ Len

[suenodelmar]

For HDPE,.High Density Polyethylene, go to Walmart or any department store and buy a Cutting Board in the Kitchen Department. They come in various thicknesses. The material is tough, sandable and impervious to moisture. Plus cheap. We just made some tapered shims with the material by s anding it with a belt sander. It does not load up the sanding belt. A disadvantage is that it cannot be bonded to GRP.

[Cheechako]

Originally Posted by Stumble

Starboard is not suitable for any load bearing application. G10 however is ideal, far better than wood since it won't rot.

I don't think Starboard is any softer than many woods that have been traditionally used. I would prefer G10 though.
OP: if you epoxy that Oak it might be fine for a long time.