25.5 bulkhead replacement

Nov 25, 2013
5
Hunter 25.5 Ruskin, FL
Hello everyone,

Both of the bulkheads on my '85 25.5 have some areas where water incursion has caused the wood to rot as well as at the bottom of the port side bulkhead next to the compression post. The block chainplate attachment and the area directly around it seems to be solid. I've read the older posts about replacing the bulkheads and I was wondering if this could be accomplished, one at a time, with the mast up. Can I loosen the shrouds on one side (one at a time) and attach them to the toe rail temporarily while I work on one bulkhead then repeat it on the other side? I'm new to sailboats and rigging but it seems like it should be doable if care is taken to secure the shrouds properly, and doing this in the slip would save a lot of money and aggravation.
 
Dec 29, 2010
67
Hunter 25.5 Point Venture, TX
Replacing the Bulkheads on a Hunter 25.5

I replaced both bulkheads and the cabin sole on my 1985 Hunter 25.5 ... but I did this while it was on the hard, with the mast down. Thus I have no direct experience replacing the bulkheads with the mast up. Regardless, in my opinion, if the compression post is in good shape (meaning that you do not have to replace it as well), then it should be possible to replace the bulkheads while the boat is in the water ... provided that you can do the work in a relatively protected anchorage/marina.

I would suggest that you remove only one bulkhead/chain plate at a time. And then I would also suggest that you fasten both halyards (rather than the shrouds) to the toe rail to support the mast. The rope halyards will transmit less shock loading to the toe rail. Fastening the shrouds directly to the toe rail might transmit enough shock loading to the toe rail to open up the hull/deck joint ... which would be very unfortunate. Distributing the load between two (or more) halyards, 18 to 24 inches apart on the toe rail should be sufficient to hold the mast in place while not over stressing the toe rail and the hull/deck joint.

In addition, I would also suggest that you use your old bulkheads to make templates from 1/4" plywood ... and then dry fit the templates ... modifying them until you are satisfied with the fit. As you are aware, the chain plates attach directly to the bulkheads. And the tension on the shrouds then pulls the bulkhead up against the underside of the deck. This is how the shroud tension is distributed to the deck/hull. (There is no tension member that transmits the shroud load directly to the hull and/or ribs.) Thus, to prevent point loading at the top of the bulkhead and subsequent point loading on the deck, it is imperative that the top of the bulkhead fit properly into the slot in the cabin top ... this is where the modifying the templates until you are satisfied with the fit comes into play.

When I did this on my boat, in some places the templates (and the resulting new bulkheads) ended up being almost 1" taller than the original bulkheads. When you remove the old bulkheads it will be obvious which portions were compressed against the underside of the cabin roof/deck for 28 years ... and which portions have been "flopping in the breeze". Modify the template accordingly.

Also, after I replaced the bulkheads, re-bedded the chain plates, tuned the rig and went sailing for 6-months ... there was enough movement in the bulkheads and the chain plates that I had to re-bed the chain plates a second time. There is no substitute for load under sail to force everything into its proper place.

Replacing the cabin sole and the bulkheads is a big job, but very doable ... and the Hunter 25.5 is well worth the effort.

Feel free to send me a PM if you have questions ... and/or if you would like paper patterns of my bulkhead templates.
 

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Nov 25, 2013
5
Hunter 25.5 Ruskin, FL
Re: Replacing the Bulkheads on a Hunter 25.5

Thanks for the advice egodsy. I see your point re the halyards. Your work on the bulkheads was one of the few I was referring to as it was very well done. Being a noob to this stuff all advice is precious and well received.

My marina seems well protected and I don't see why this can't be done there while the boat is in the water. I will have to be careful and I do understand that its a big job, however the rot I found seems to be typical of neglected chainplate bedding with these boats and If I can fix it now, before spring and summer, I think I'll feel much more secure in the long run.

I will take you up on those patterns when I get ready to do this and may PM you for detailed advice when I get started. I will also be replacing the cabin sole. Thanks again for the positive reply.