Advice on bulkhead replacement?

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Poda
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Advice on bulkhead replacement?

Post by Poda »

I posted this on another site and got a few good answers, but with the wealth of knowledge here prompted me to copy the thread here and ask for your input..

So both bulkheads on my Northstar Farr 727 need replacing and I have a couple of questions.

The boat has a fiberglass inner liner on both sides of each bulkhead and everything I've read so far indicates that these liners aren't structural. In order to properly cut out the bulkheads, I'm imagining I'm going to have to cut out portions of the liner on each side (the entire galley area in the first and second pic for example) using a rotozip or some such tool, and 'glass these sections back in when I'm done. Is this how you guys would do it? Or would you subject yourselves to contorting like an epileptic snake in tiny spaces?

I'm also unsure how to proceed where the bulkhead is (more than likely- or at least SHOULD be) tabbed to the deck. The headliner is one big solid fiberglass piece from the anchor locker to the companionway and if I cut out that middle section it would be a royal PITA to 'glass back in. Any advice on how to tackle that?

Lastly, I fully intend on re-bedding the chain plates and taking the time to do a proper job of sealing her up tight. But I never want to have to do this again.. other than G10/FR-4 fiberglass board (which seems extremely expensive at $1000+ for a 4x8x.750 sheet - if you have sources for cheaper by all means let me know!), is there any material other than wood that I can use that won't rot or otherwise compromise the strength and rigidity of the boat? The lack of the "wood" look is not a concern - there's going to be enough of it elsewhere (and some small cabinetry on the bulkheads) to keep the cabin "warm".

I've attached some pics to give you an idea of what I'm working with.. the v-berths on the other side are of similar construction and attach the same way to the hull (tabbed)/bulkhead (bolted) as starboard berth in the 3rd pic, but it's its own separate liner. Don't mind the skinny guy bent over in the pics- I'm obviously too engrossed by something to get out of the way when the girlfriend took these.

Image

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Case
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Re: Advice on bulkhead replacement?

Post by Case »

Some close up pictures of the bulkhead attachment would be helpful.

Most times, sailboats with a hull liner like that... The bulkheads often are just screwed in with some fiberglass tabbing (often none for this size range). Its relatively easy to replace them compared to boats with a full stick-built interior (wood only, no fiberglass stuff). But on the other hand, many boat builders do things oddly that makes it real hard to replace things...

- Case
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Re: Advice on bulkhead replacement?

Post by Tim »

G-10 is not a good choice for bulkheads for several reasons: cost, weight, and workability.

If you want a non-wood replacement, consider something like Coosa board, or one of the structural honeycomb-type composite products such as those sold by Nida-Core, among others.

As Case mentioned, check to see if your bulkhead is actually glassed in place. In boats built like yours, they're often just screwed to the liner and a cinch (relatively speaking) to replace.

If indeed you have glassed-in bulkheads, you've no choice but to remove enough of the liner to work satisfactorily. Feel free to curse the production builders frequently as you work through the job.
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Poda
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Re: Advice on bulkhead replacement?

Post by Poda »

Thanks Case..

The bulkheads are tabbed to the hull, and bolted to the liner. Probably because the chainplates attach to the bulkheads, not the hull. My thoughts of having to cut out the liner stem from the realization that I'm going to have to clean up those edges and re-tab the new bulkheads.

Here's a pic from under the galley.. for what it's worth, if it was only this section that was gone I'd cut out the rotten section and glass in some new plywood. But examination on the v-berth side revealed rot on close to 3/4 of the bulkhead. Same for the other side.

Image

Tim: Looks like I'm going to be cursing up a storm... And thanks for the non-wood alternatives info.
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Re: Advice on bulkhead replacement?

Post by Quetzalsailor »

Perhaps the boat was assembled from bow to stern, trapping earlier parts with later parts. Not a helpful way for later repair work! (Our LeComte was done pretty much the same way; I had to demolish/modify casework components in such a way that reassembling them was possible.)

I'd go fairly far (Farr?) out of my way to avoid sawing things, like the fiberlass liner components, out that aren't bad and would change the appearance. Looking at the port side, perhaps you could demolish the wood and replace it with a horiontal seam concealed by that sink counter flange; the structure could be regained by using a backer installed from the forward side. That way, you could get the sized pieces in w/o awful demolition. Ditto, for the starboard side but you'd have a butt seam, which could be battened or trimmed,and again use the backer from the forward side.

You could reuse the existing tabbing, if you could get it clean enough to butter the new wood with epoxy and bond the cleaned tabbing to the wood.
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Re: Advice on bulkhead replacement?

Post by Case »

I somehow missed the comment about using G10 as a bulkhead. That's really HEAVY and costly. Wood is a great material, you just need to seal the holes in the deck to prevent the wood rotting away. By the way, if the bulkheads are rotten, then the core in the deck penetrations (chainplates, stanchions, etc) probably are rotten, too. Nothing wrong with using wood again, really. It's poor maintenance that did in the wood parts.

Try unbolting the bulkheads first before doing anything more destructive. Its possible that the tabbing ain't holding all that strongly. Remove most of the wood before doing anything to the liner itself so you can see how much liner you actually have to destroy.

Good luck with your project!

- Case
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Re: Advice on bulkhead replacement?

Post by Poda »

Quetzalsailor wrote:Perhaps the boat was assembled from bow to stern, trapping earlier parts with later parts. Not a helpful way for later repair work! (Our LeComte was done pretty much the same way; I had to demolish/modify casework components in such a way that reassembling them was possible.)

I'd go fairly far (Farr?) out of my way to avoid sawing things, like the fiberlass liner components, out that aren't bad and would change the appearance. Looking at the port side, perhaps you could demolish the wood and replace it with a horiontal seam concealed by that sink counter flange; the structure could be regained by using a backer installed from the forward side. That way, you could get the sized pieces in w/o awful demolition. Ditto, for the starboard side but you'd have a butt seam, which could be battened or trimmed,and again use the backer from the forward side.

You could reuse the existing tabbing, if you could get it clean enough to butter the new wood with epoxy and bond the cleaned tabbing to the wood.
When I get back to the boat this weekend I'll take a look with your idea in mind and see if I can work something out. Interesting suggestion to re-use the tabbing, it's getting me to think of a compromise between what you suggested and the full scale demolition I was initially contemplating..

I don't mind cutting out roughly 2ft sections of the v-berth - I can either rebuild using wood, or glass back in. Either way, most of the resultant damage and fix should be covered by the v-berth cushions. (Much easier than new casework or satisfactorily glassing and finishing the galley back in). Then I can work my way back from there - cut out the bulkhead with a rotozip set to just shy of the width of the bulkhead and clean up the (hopefully intact) tabbing on the aft side. Butter the bulkhead in epoxy to bond to the aft tabbing, new tabbing on the front side, re-glass in v-berth section, and good to go..

Thoughts?
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Re: Advice on bulkhead replacement?

Post by Poda »

Case wrote:I somehow missed the comment about using G10 as a bulkhead. That's really HEAVY and costly. Wood is a great material, you just need to seal the holes in the deck to prevent the wood rotting away. By the way, if the bulkheads are rotten, then the core in the deck penetrations (chainplates, stanchions, etc) probably are rotten, too. Nothing wrong with using wood again, really. It's poor maintenance that did in the wood parts.

Try unbolting the bulkheads first before doing anything more destructive. Its possible that the tabbing ain't holding all that strongly. Remove most of the wood before doing anything to the liner itself so you can see how much liner you actually have to destroy.

Good luck with your project!

- Case
After pricing out honey-comb materials and such, I'm going to stick with wood.

As for the deck-leaks, I'm pretty sure it's not from deck penetration. The boat sat for quite some time with hatches open, etc and a lot of standing water penetrated (thank god it's all plastic!). You can see the watermark levels in the pics. The bulkheads from the deck down to about 6-12" depending on the spot is pristine. It's obvious they rotted from the bottom up with lessening degrees of softness as you work your way up, as opposed to the top-down I'd expect from a deck leak - by all means correct me if I'm wrong in this assumption.

While the deck isn't soft anywhere (including stanchion bases and chain plates), I fully intend on properly removing and re-bedding the chain-plates during this bulkhead replacement. Since I have to remove the plates anyway, ultimately time will tell if I'm right or wrong. If I have to re-core that area however, oh well - it'd be annoying but not completely unexpected given the age of the boat.

Thanks for the heads up and advice though - always appreciated! Will follow the "unbolt first" approach for sure.
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Re: Advice on bulkhead replacement?

Post by Tim »

Don't blame the plywood for the rot you have: blame years of ignorance and neglect.

Plywood is still an excellent choice for bulkheads and structure, and is extremely cost-effective--even the good stuff.

It's really not very hard to maintain a boat so that things don't rot out. There's no reason that new plywood won't last indefinitely as long as no one lets the boat sit with pooled water everywhere.
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Re: Advice on bulkhead replacement?

Post by Figment »

Poda wrote: I don't mind cutting out roughly 2ft sections of the v-berth - I can either rebuild using wood, or glass back in. Either way, most of the resultant damage and fix should be covered by the v-berth cushions. (Much easier than new casework or satisfactorily glassing and finishing the galley back in). Then I can work my way back from there - cut out the bulkhead with a rotozip set to just shy of the width of the bulkhead and clean up the (hopefully intact) tabbing on the aft side. Butter the bulkhead in epoxy to bond to the aft tabbing, new tabbing on the front side, re-glass in v-berth section, and good to go..

Thoughts?
That's essentially what I did.
Though my boat has no headliner, I think I'd approach your headliner problem the same way. Make every effort to leave things undisturbed aft of that bulkhead, but sacrifice (possibly replace or rework) everything in the v-berth compartment.

Would it really matter if it's tabbed to the deck from only the forward side?
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Re: Advice on bulkhead replacement?

Post by Poda »

Tim: Don't get me wrong, I have no problem with wood, and after all this work I guarantee I'll be maintaining this boat meticulously. But after the anticipated cursing, cuts, bruises, frustration, and resulting anger-management therapy I was thinking that a more rot resistant material might make me happier and give me peace of mind in case I fail to notice a slow leak from somewhere. That said, I agree that wood is a great bang-for-buck, and that properly maintained I'll never have to do these again regardless of material used.

Figment: Thanks for the confirmation.. Headliner may just go in that section of the boat. Really, it's only for sail and misc storage, and the only person right now who is capable of sleeping or spending extended amounts of time in that small space is SWMBO's 9yr old son. He'll be too psyched to be sleeping aboard to care about cosmetics..
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Re: Advice on bulkhead replacement?

Post by Shark »

Welcome to the forum.

One of the advantages of owning a one-design sailboat is that there is often a class association. These associations are excellent sources of information about your boat including owners' forums and advice on everything from racing tips to restoration.

In my time sailing in western Lake Ontario, I have only seen a couple of Farr 727's but I know they were more popular elsewhere, for example Australia and New Zealand.

Here's the URL for the New Zealand Farr 727 Association http://www.farr727.org

I'm sure you'll be able to find more information about your boat on the web. Good luck with your restoration.
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Re: Advice on bulkhead replacement?

Post by Poda »

Shark - thanks for the info - I'd found that site already but it's remarkably light on info considering its popularity down in NZ.

Now that I've got a plan of attack for the bulkheads, I want to run my hull-support idea by you guys..

Given the relatively small size of the boat (24ftx8ft beam), will the hull deform once I remove them? I know it's an issue on the larger boats. Since the boat is already on a cradle, and I don't have access to additional stands, I thought of cutting out braces out of 4x4's shaped to contour the hull using the tick-stick method (and carpeting the hull contact points..), backing them with something sturdy at the thinnest points, and strapping the braces to each other using straps running over the deck and under the hull. Sort of like this (straps in green):

Image

Would it be necessary to additionally brace it to the ground at a 45 degree angle or so?

I'm not completely up on terminology, so forgive me if I'm butchering the terms..
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Re: Advice on bulkhead replacement?

Post by Case »

Your sailboat was filled with water. It probably froze, too. The weight of the water would have deformed the hull by now. I don't see any dimples in the hull in the pictures I can see. That means the boat will be fine with no bulkheads!

My 23 foot Sea Sprite 23 doesn't even have bulkheads, you know. It's not heavily built, either. The hull is still holding up fine.

- Case
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Re: Advice on bulkhead replacement?

Post by Poda »

Good to know Case!

I took a closer look last weekend when I was at the boat, and sure enough there's no dimples, hard spots, oil-canning or anything else on the hull that suggests it's deformed in any way at this point. Yay!

So now I'm just waiting for the boat moved much closer to home in October before tackling these bulkheads, so it's on to the next set of projects (and threads, hehehe). Incidentally, I knew I wasn't going to catch everything that needed to be done on initial inspection, and I've found my first "doh! Didn't know that was there" nasty surprise on the spreaders while packing up the things that I can work on at home. But that's another topic, coming to a friendly neighbourhood thread near you this afternoon...
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