Moving chainplates outboard

ggrizzard · Dec 14, 2020

So would I.

sailme88 · Dec 14, 2020

Wow ! Would you be changing out your spreaders? How would you deal with the old chain plates? If they were leaking with the rigging, they should leak without the rigging. Would you remove the old chain plates and re-glass the area?

Michael Davis · Dec 14, 2020

I’ve seen that done with a Hans Christian 38. It does change the sheeting angle for the jib slightly so you will not point quite so high. But it is a cruising boat so maybe that’s not so important.

Don S/V ILLusion · Dec 14, 2020

Doing that would likely require substantial reinforcement of the area where the new chainplates would attach as well as structural reinforcement to eliminate point load stress on the topsides. The FRP below the toe rail isn’t intended to or designed to withstand that load. Done correctly, it is a viable alternative.

sailme88 · Dec 15, 2020

Angus Fleming said:
Sailme88, do I need to change out my spreaders? The holes would be filled and reglassed and I'd be reusing the Chainplates.

If you move the upper chain plates you WILL need to replace the spreaders. When the upper meets the spreader it has it's angle changed from roughly 45 degrees to 90. Moving the upper chainplates outboard without changing the spreaders will change the angle of purchase from pulling down to pulling somewhat outward..

RoyS · Dec 15, 2020

Regarding "dashing forward"; you may want to try bringing the mooring ball alongside about mid-ship instead of at the bow. Then leave the helm, walk forward and pickup the line, haul it in tight and walk it to the bow. You still have to get around your shrouds but no dashing or critical timing required.

Don S/V ILLusion · Dec 15, 2020

Angus Fleming said:
Don, Some good points, the current chainplates attach to fibreglass knees between the topsides and the deck and I was hoping the new attachment points would coincide. What scale of reinforcement would you envisage?

I understand you are seeking opinions but (in my opinion) this isn’t one of those decisions which can be made on opinions. Absent knowing the design loads necessary and the working load created by relocating the chainplates, this is a ‘do you feel lucky’ decision.
I think it’s irresponsible for anyone here including me to suggest dong this without consulting capable sources.

Rick D · Dec 15, 2020

Angus, a dock mate of mine years ago did the same as you suggest to his Catalina 30 for the reasons you outlined and because he believed they would provide superior support. Long story short, he has major structural failure off Mexico and had to abandon the boat. If you ar serious about continuing, i would urge you to employ a marine architect to provide engineering and plans.

MikeHoncho · Dec 15, 2020

The ends does not justify the means....in my opinion. If I could change anything on my H30 it would be to relocate the chainplates due to trying to get around them but wow, that is a lot of work. Engineering, fiberglass patch, and reinforcement, new, custom chainplates fabed, new standing rigging x6 plus probably new spreaders plus designing it so you have access to the chainplate backers (cabinets). All for some well-placed butyl tape and stepping up onto the cabin and around the rigging.

David in Sandusky · Dec 15, 2020

The recurring question: Can I change part of an integrated boat design that has performed well for years? Again and again, the answer comes out: Yes, but you need guidance from an expert marine designer, the cost is usually more than selling the boat then buying one that better fits your needs, and there are unknown negative consequences when you want to sell the boat.

sailme88 · Dec 15, 2020

In the final analysis you must weigh against what might be lost vs what might be gained. Figuring predominantly in this equation should be what if the change fails and someone is hurt or worse...Insurance company underwriters have digests to aid them in establishing the stability and other reliability aspects of boats. So, maybe you might want to run your plan past your insurer...

Jackdaw · Dec 16, 2020

While this COULD be done, for your need its not worth the effort.
For sure new longer spreaders, and new shrouds.
The hull laminate would have to be built up in that area to take the loads
Throw away your genoa, you are a jib-only boat now.

I'd have a marine engineer certify the design and construction.

But here is the biggie - Doing this indeed make getting around your vertical shrouds easier, but your diagonals HARDER. They now cut across the entire side deck, and at a lower angle. Many boats with outboard shroud separate the set, and move the Ds WAY inboard to keep the sidedeck clear.

BlueJ has hull mounted shrouds... you can three areas of addition laminate stacked under the chainplate bolts.

Kings Gambit · Dec 16, 2020

Angus Fleming said:
Hi all, I was reading the replies to joe28532 's leaking chainplates problem and don't want to hijack his thread.
I have been wondering for some time about moving the shrouds and chainplates outboard. If the chainplates were mounted externally on the hull then there would be less chance of leaking and be easier to inspect.
My H37c lives on a swinging mooring during the season and I'm regularly dashing forward through the shrouds to catch the mooring.
One of many reason's I like this boat is the wide side decks and moving the shrouds out would clear the route forward. I presume it will serve to improve the stability of the mast.
OR am I missing something ?
I would welcome the group's thoughts on the matter
Regards, Angus

It might be better to work on pennant pick-up rather than reconstruct the boat. Perhaps a long streamer from the mooring can that you can pick up alongside and quickly clip (transfer) to a rode leading from the bow chock. Then go up with less urgency to finish the job, etc.