add backing plate how support side stay ?

[xxhat]

going to add a backing plate to the main side stay on a cape dory 28.

will be using main halyard in place of side stay as i loosen the side stay.

problem is what do i attach main halyard to ?

stanchions do not seem strong enough and if i use a line attached to main winch and front cleat the angle is wrong.

nothing else to attach to.

thanks

[Steve Laume]

The backing plates on your boat probably do the work for the uppers and lowers on each side. Cape Dory used mild steel on the earlier boats and it is going to be a fair amount of work to replace it. This means it might take a while. The best way to do this job would be to pull the rig so you could do both sides if necessary with no worries about supporting the rig.

If you need to do it with the rig up , for some reason, you could slack off the tension on both sides and support one side with your halyards. Those stanchion bases should be strong enough to do the job. Running the main and jib halyards to a couple of bases would probably suffice. You could also run another line up around the spreaders, before you detune and tie that off as well. The mast isn't going to go anywhere.

You might see just how hard it is going to be, to gain access to the backing plates before you start to mess with the rig, Steve.

[Dave and Kathy]

I have a 1984 CD 28. It's not clear to me what you mean by the term "main side stay." The CD 28 has an upper stay and two lower stays on each side. If the backing plate will be for the upper stay (main side stay?) and you're doing the work with the mast up, the forward and aft lowers will still be in place on the side you're working. The main halyard tensioned to a stanchion base plate on the side you're working, together with the lowers on that side, should be fine. I also agree with the advice to scope it out first. By 1984, Cape Dory was using aluminum backing plates and the only reason I'd work with ours would be to re-bed them.

[mgphl52]

By 1984, Cape Dory was using aluminum backing plates and the only reason I'd work with ours would be to re-bed them.

Do you know what was used 1982?

[Steve Laume]

In 1982, you get mild steel. Cape Dory seems to have realized that steel was not such a great material for that application sometime in late 1983 or early 1984.

I am pretty sure the backing plate will be utilized by all of the stays on each side. As in, one long plate that all of the shrouds are bolted to. Still no reason whay you can't take it out by securing the halyards to the stanchion bases.

Cape Dorys are notorious for bad wiring but I would add bad welding to that.

You should dig around in there to see just what you are getting into. There will be a lot of discussion on the chain plates if you use the search function. There are lots of owners that will feel your pain. When you do replace them, use aluminum or stainless steel. The later boats used aluminum and it is much easier to work with than stainless.

Supporting the mast really isn't much of an issue, Steve.

[Jim Walsh]

Agree with Steve. If you decide to replace the backing plates aluminum makes a lot of sense. Easily obtainable, easy to work, and a proven track record in that application. I have gone through the trouble to expose and inspect mine and they are in fine condition.
Stainless, titanium, or bronze would be alternatives but would be very expensive and much more difficult to work with. The use of G-10 or some other composite would require in-depth research to determine applicability.

[xxhat]

Yes, upper side stay.

Am going to use half inch G10

Stanchion base seems flimsy but not much choice.

[Seaweed2]

My plates on a 1975 CD28 are a bit rusty themselves and will likely be replaced early in this season. I plan to step the mast so I will have plenty of time to do a well planned repair. The backing plate is nearly three feet long and has fingers welded that are perpendicular and have been fibreglassed to the hull. Looks something like rebar welded to the backing plate. Hard spot to get into to do all that work. If you needed to do it with the mast up and there was a chance of any wind, you might also consider running a line or two under the keel and tying off on the other side of the boat. Might even do that as a safety measure anyway. Best of luck, and consider that a job worth doing is worth doing well. I found this to be valuable when approaching most projects on the boat.
The website below talks about someone elses view of the whole chainplate issue.

https://missionmariah.wordpress.com/201 ... te-design/

[John Stone]

Concur with Steve L. I’d recommend you gain full and complete access to the chainplates before you loosen the shrouds. Your project is very doable but you are going to need the right tools and it is going to be a messy job.

I’d take apart any necessary cabinetry and get a good and complete look first. Determine what tools you will need e.g. right angle grinder, Dremel Multi max, wrecking bar, DA sander or grinder with min of 40 grit abrasive, 17ox biaxial tape, epoxy, and fillers and fairing compound. You’ll also need bedding compound, a good vacuum, and appropriate respirator. Id strongly recommend doing both sides since you will have the boat set up for it and all the tools on hand.

It’s a small point but terminology is important when dealing with complex machines like a sailboat. Stays position the mast fore and aft. Shrouds position the mast laterally—side to side.

Stays: Headstay (the jib attaches to it), forestay (the stays’l attaches to it), backstay, bobstay.

Shrouds: Cap shroud (sometimes called an upper), Intermediate (correctly called aft intermediates on a single spreader cutter rigged boat like most CDs. The Far Reach has true intermediates since she has double spreaders and the intermediates are parallel to the cap shrouds and provide no support to counter the forestay. We use runners for that). Last are the fore and aft lower shrouds.

[mgphl52]

In 1982, you get mild steel. Cape Dory seems to have realized that steel was not such a great material for that application sometime in late 1983 or early 1984.

Well that's a bummer... but at least now I know. Thanks for update!

[Frenchy]

John Stone wrote

I’d take apart any necessary cabinetry and get a good and complete look first.

John, is it possible to dismantle and re-assemble the cabinetry without too much damage? - Just
wondering, in case. Thanks, Jean

[John Stone]

I don’t know the CD 28. But some things can be disassembled. It will almost certainly require removing a few wood plugs. I often read about folks trying to save plugs. It’s easy to make new one with a simple drill press and plug cutter. Or purchase a package.

Take doors off and remove them. Remove trim if it’s in the way. Ensure you have as unfettered an access as you can possibly manage before you get into the meat of the project. Nothing worse then getting hot and sweaty and almost there and you can’t quite get to the last bolt or get the crowbar or grinder positioned properly. Then you get mad and frustrated and start swearing and your boat’s feelings get hurt and good grief it takes a long time to get all that sorted out.

The bottom line is the more you can remove the easier, and thus the better, the job. Be patient. And as always, remember the first rule is “do no harm.”