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Need advice on bulkhead replacement..

8K views 28 replies 12 participants last post by  tommays 
#1 ·
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 rebedding the chainplates 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/bulkhead as starboard berth in the 3rd pic, but it's its own seperate 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.





 
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#2 ·
The bulkheads could have been inserted between the sections of interior liner before the deck was installed. I have found that, by reversing the construction process, I have the best access for the repair. Look closely to see if the bulkheads are tabbed in to the hull or sandwiched in to the interior.
 
#3 ·
Thanks xsboats.. they're tabbed to the hull, which is why I immediately thought of cutting out portions of the liner for access.
 
#4 ·
#6 ·
Awesome! Just took a quick look and ended up ordering the book for ~$15.. Should be here in a week..

Thanks for the tick stick info - I was wondering how I was going to reproduce those curves seeing as these bulkheads will more than likely self destruct when i remove them..

... and this is why I come to sailnet.. always good advice here :) Keep it comin'!
 
#9 ·
I spent the better part of yesterday afternoon trying to google this particular thread, and looking for it on BoatDesign.. I found a really informative one on a guy with rot and termite problems on a Cal 25, but not the one you mentioned.. Care to link an obviously poor googler up? :D

svHyLyte: The pics are deceiving. The bulkheads rotted from the bottom up because of some previous standing water in the boat (thank you PO!). The damage on the port side is what you see aft looking forward. If that's all there was I'd do what you suggested and just cut out the section. Unfortunately, when you look at these from the bow looking aft, they're completely delaminated and spongy from the bottom to about 6-12" from the headliner, depending on the spot. Above that is solid, but without more solid material to work with I'd rather just replace the whole thing.
 
#8 ·
Perhaps I missed it but why are you replacing the entire bulkhead? If you have some rot (perhaps from poorly bedded chainplates), it would seem wiser, and much easier, to cut out the damaged material and replace it with a sistered backing panel than to attempt to replace the whole business, no?
 
#10 ·
...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".
If it were me, I would use marine plywood, and seal it up with a few overcoats of clear epoxy, obviously paying particular attention to the endgrain. If I were feeling good about my time and budget, I would add a step of layering on a sheet of cloth over it to aid in the sealing up. It's pretty tough to beat plywood for cost, strength, etc. It also takes a long time to get really damaged in this situation considering that its horizontal. So if you are addresing the boats other issues, I would think that this would be a one-time repair for you whether using G10 or plywood.

I'm in the middle of a stripped-to-the-hull refit at the moment, and have had some similar decisions, although far less dramatic than yours. I'm pretty happy with the strength and durability of plywood, especially when weighed against the cost of pre-made fiberglass board. I'm only using that stuff for backing plates.

-Chris
 
#11 ·
I agree with epoxy coating marine ply and going with that..If you get a couple good coats on.... water will for all practical purposes have zero chance of entry....It will last longer then you want to keep the boat lets put it that way.

A simple step that if all manufactures would have done it back in the day, would have saved mamy a heartake for ownwers down the road.
 
#12 ·
bulkhead 727

Hey TintedChrome, I did a bulkhead and mast plate reconstruction on my Northstar 727 back in 2001. I still have the boat and race it all the time on Lake Ontario. Where are you?
I could explain in detail how I did it but want to make sure you are still looking for assistance before I write it all up. Alternatively you could contact me for info on this and whatever else you would like to know about this great little boat. Send me an email and i'll give you my phone number so we can speak one on one. I have 10 years of experience on this boat and would be happy to share what I have learned. I think I still have a set of templates for the keel laying around if you plan on attacking the bottom at some point. The bulkhead replacement was tough work but I did not cut on the boat or liner at all as I replaced it in three pieces.
I just removed all the hardware from the deck and painted it this past spring. I also ordered new sails for next season from Haarstick so I plan on keeping it a few more years; at least till the kids get done with college. Anyway, look me up if you want my help. As I said I'd be happy to help out anyway I can.
Brian
They wont let me place an email address until I have 2 posts to my credit. watch for new posts
 
#16 ·
FWIW you may want to reconfigure that email address so spam bots don't get it.
 
#17 ·
I've repaired both the port and starboard bulkheads on Victoria. On the port side, the entire bulkhead was replaced. On the starboard side, I replaced a small section. In both cases, the new sections were tabbed to the hull. I used exterior 1/2" high density ply and laminated it with formica (port side) and teak (starboard side). The panels were tabbed into the hull with high density roving and West epoxy. All in all, it's not really a hard job. PMM me if youy have questions.

Photos follow:

S/V Victoria Head Reconstruction

VICTORIA Starboard Bulkhead Repair
 
#19 ·
Sabreman: Thanks for the info! It's always great to see how people do certain jobs!

Brimur: The offer for assistance is greatly appreciated :) I have a fair idea of how to attack the problem, but would love to hear your take on it. I'll be sending you an email separately..

Where on Lake Ontario are you? Boat's in Whitby, but it'll move to a storage yard in Toronto in October, and moored there next May.

As for the story behind the boat - I bought it from a kid who had grand dreams and little money to fix the issues..

The story behind the boat is quite interesting actually (which leads me to think you probably don't know this particular boat)..

About 5 years ago, boat shows up at the marina in Whitby, Ontario in transit from Montreal Quebec. Guy says he wants a slip for the night and he'll be gone in the morning. He ties up the boat, leaves to go get groceries or something, and never comes back.

Eventually the marina seized the boat, sold it at auction to one of its employees who already had 3, and he sells it to his friend as a "great way to get into sailing". Unfortunately for him, he's bitten off more than he can chew, and can't afford the storage fees, etc.. after 3 years, I got the boat for the current season's outstanding fees and a case of beer.

She's rough, but the bones are good, and she's complete. No delam in the hull, no oilcanning, no blisters, decks are rock hard.. Not to say there aren't some issues here and there, but the boat is far from rotten. Stanchion bases are still great with no softness - only the area where the chainplates enter the hull requires recoring/rebedding.. I'm sure I'll get some nasty surprises (and actually expect some), but overall I'm extremely happy with her.

In case you know the boat, her original name was Lickety Split..
 
#20 ·
One small comment regarding the type of plywood.....

When I started repairing our bulkheads, I went in search of marine ply. Since I live about 70 miles from the marina, it is very difficult to acquire marine ply in our home area. I really didn't want to make a special purchase through a local mill yard due to the extreme cost. I used my wife as a sounding board and she asked why it had to be waterproof. I replaied that it was for the boat, etc. When she pointed out that this was for an interior use and should NEVER be wet, the logic was hard to dispute.

I know that this is sacrilegious, but I went with a high grade, multi-ply (7 layers) exterior plywood. I feel that for interior applications that will not come in contact with water, exterior ply is adequate. Indeed, Sabre used marine ply and due to leaky chainplates, it rotted. So it seemed to me that if I keep the chainplates sealed properly, I had nothing to worry about. So far, there is no issue with either bulkhead and I expect that there will be none in the future.

On the other hand, if I was building a plywood boat, marine ply is the only way to go. It's just that marine ply didn't do us much good in the original application so I didn't feel a need to get too twisted about using "Marine" ply - exterior ply was sufficient for an interior application.
 
#21 ·
Sabreman - That's a good point.. isn't it great when someone that's relatively detached from a situation offers an alternative to the "this is how it HAS to be done" tunnel vision that sets in?

Given the abuse and rougher weather this boat will likely encounter, my biggest concern is strength and rigidity. If the ply (outdoor or marine) is coated in epoxy to seal it anyways, holes for chainplates drilled oversize-filled-re-drilled, all things being equal it should be watertight and I'd make the assumption a high-quality outdoor ply is a lot more cost effective with all the same attributes as marine.

Like you say though, in a more exposed environment I'd go for the marine ply in a heartbeat.. like when I build my cockpit lockers..
 
#23 ·
like when I build my cockpit lockers..
That makes sense since it will be exposed to the elements. No question; we're in total agreement.

In the case of an interior bulkhead, there should be no moisture at all! I certainly don't want the cushion next to it to have any moisture on it, so why should I be concerned that the would will delaminate if it's submerged? If it's submerged, I have way more problems than concern over delamination!
 
#22 ·
From wanting Garolite G-10 to exterior plywood is quite a transition in quality...

Anyhow, about G-10 - I just cut some backing plates out of it. It's a nightmare to work, it's basically like cutting solid glass. I wouldn't want to do big projects with it unless there was no other way. I was going to replace some weathered stand-offs for my hatch hinges & chocks with it, but after cutting the backing plates I've decided to just epoxy-coat wood instead. Much easier to deal with.

As for exterior plywood, I don't see how you'll get a decent finish with it, and it's not as structurally sound as marine plywood (but maybe that's balogna - I'm not an expert). You might be harming the boat, since you'll probably need to use the same thickness as the marine plywood you're replacing. It will definitely delaminate easier than marine plywood, the glue job doesn't compare.

I'd try to find a source for marine plywood if I were you.

I'd also just grab the multi-tool and chop things out wherever there isn't liner, and then see if you can remove the stuff that's between the liners. Maybe you'll get lucky. Wouldn't cut the liner as a first action, but only as a last resort. It looks like you have pretty good access to the bulkhead in your pictures.
 
#24 ·
tinted chrome, did your book come in? when it does i like your thoughts on it, i think it is full of great projects w/good illustratons... just curious
 
#25 ·
As for exterior plywood, I don't see how you'll get a decent finish with it
I generally agree, because fir is hard to finish, but if properly sealed prior to final coating an acceptable finish can be achieved. But for my interior, I prefer some sort of veneer. I used teak veneer over the ply for one bulkhead and formica for the other. I bond the veneer with Tightbond II or III. Sabre used 1/2" teak veneer marine ply with 5 laminates. I used exterior ply with 7 laminates and did my own veneer. The result is the same thickness. The result is at least as strong as the original construction.

Veneering is not that difficult, relatively inexpensive, and does not necessarily require specialized equipment. For small panels, clamps can be used. Larger panels require a vacuum bag or can be bonded with contact adhesive. The later requires an extra step to seal the veneer prior to finishing, but if done properly, will not delaminate and the bond will strengthen over time. Contact Adhesives don't like solvent finishes, but if the veneer is sealed with dewaxed shellac prior to finishing, there will be no delam. Just a few time-honored tips.... don't mean to hijack the thread. :)
 
#26 · (Edited)
QuickMick - My original order didn't ship - i think they realized that $6+ shipping for the book was a problem.. Found another copy for ~15, and I got shipping confirmation on Tuesday! Should be here today or Tuesday (Monday's a holiday for us north of the border [Edit: looks like it is for you too! My bad..]). I'll definitely let you know what I think!

LookingForCruiser - I was exploring the g-10 as a full-blown wood alternative, but after realizing that ply can do the job and should last as long as I maintain the boat I've dropped it from my radar.. I'm doing a bunch of research right now on exterior vs marine grade ply. It seems a major difference is the tolerances for voids between the layers. I.e. marine has none, exterior allows for some which concerns me a little bit seeing as chainplates are bolted onto it. For lake sailing it would be a no brainer, I'd go with the exterior ply. However there's some offshore in this boat's future and the higher loads that it entails. That said, I see that Sabreman's chainplates are bolted to his. Aaaahh... decisions, decisions!

I have plenty of time to work this out.. the 'heads aren't getting done until mid October when the boat gets moved (much) closer to home.
 
#27 ·
Good exterior plywood uses waterproof glues but as posted above there are voids that do not exist in a good marine ply like Joubert, Aquatek or Hydrotek ply. The marine ply has more plies for a given thickness as well. The 3/4" Hydrotek I used is 11 plies and the 3/8" I used is 7 plies - all void free. Occume or Meranti that is used in marine ply is a more stable wood than fir and nothing in domestic exterior grade really compares. All plywood will eventually rot if it gets wet and stays that way. So you're getting more strength, probably better quality glues, no voids whatsoever, and more stability with marine ply. It finishes better if you are painting it as well. The Hydrotek I used is best I have had the pleasure of using in decades.
My local supplier in Victoria, Westwind Hardwood, has domestic fir marine ply listed in their catalog but it has not been available in good quality for a long time so they do not stock it.
 
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