Lagoon 440 bulkhead separation

[workmaster2n]

I was on a 440 today and had read about bulkheads not being tabbed in and only being adhered to the hull. I took the drawer out of the forward port bed and took the following video. Bulkhead separation?

I understand this isn’t a cracked bulkhead, but is this an issue? I’ll get a surveyor to take a look if I decide to go ahead, but was just curious if this is par for the course with 440s.

[GordMay]

Lagoon Bulkheads ➥ https://www.cruisersforum.com/forums...-266761-9.html

[massnspace]

It looks like you have a separation between the bulkhead and the hull, which I don’t think was the same problem the others had. I thought their issue was the bulkhead itself was splitting apart.

I do not own one, not an engineer; just my opinion. Best to have a professional look at it.

[Jimbo2010]

you don't need a surveyor to tell you it needs a repair, while your at do all of them.

Not a big deal with a good fiberglass guy

[Jenta]

As I'm sure others will mention, the 450 issue is not applicable to the 440's at all. But, as is true with any boat, the bulkheads should be inspected and cared for.

For the 440 it seems that over the years Lagoon varied their process slightly and some boats are essentially glued at that seam you show while others are secured with fiberglass from the bottom up maybe a couple feet. We have several areas now where the adhesive has aged enough that it no longer can flex and has weakened in some way and we now have some cracks in adhesive only areas. They are not a structural concern in and of themselves, however we notice that we have more creaking underway in our wood cabinets and such in moderate seas as the years have passed and it's time that I start working on these areas by removing the adhesive and tabbing them properly with fiberglass. The assumption being that each area like that allows more flexing which in turn causes more cracks like that which allows more flexing, and so on.

None of ours are as long or jagged looking as that - but I don't think that would scare me away from a purchase just by itself. But it WOULD make me spend good money to have someone that knows 440's doing an extensive survey so you will know ahead of time what you're getting into and make that part of the necessary repairs for purchase. Whether they fix it or discount the price, whichever works for you.

That could just be fatigue from age and hard passages, or it could have been a hard grounding so be thorough. We love our Lagoon 440 and have seen 440's with major lack of tabbing and lots of cracks like that and misalignment of things that would make your eyes water and they are still sailing along and able to be brought up to snuff to the point they are better than new.

But it IS dusty itchy work in tight places

[workmaster2n]

Originally Posted by Jenta

As I'm sure others will mention, the 450 issue is not applicable to the 440's at all. But, as is true with any boat, the bulkheads should be inspected and cared for.

For the 440 it seems that over the years Lagoon varied their process slightly and some boats are essentially glued at that seam you show while others are secured with fiberglass from the bottom up maybe a couple feet. We have several areas now where the adhesive has aged enough that it no longer can flex and has weakened in some way and we now have some cracks in adhesive only areas. They are not a structural concern in and of themselves, however we notice that we have more creaking underway in our wood cabinets and such in moderate seas as the years have passed and it's time that I start working on these areas by removing the adhesive and tabbing them properly with fiberglass. The assumption being that each area like that allows more flexing which in turn causes more cracks like that which allows more flexing, and so on.

None of ours are as long or jagged looking as that - but I don't think that would scare me away from a purchase just by itself. But it WOULD make me spend good money to have someone that knows 440's doing an extensive survey so you will know ahead of time what you're getting into and make that part of the necessary repairs for purchase. Whether they fix it or discount the price, whichever works for you.

That could just be fatigue from age and hard passages, or it could have been a hard grounding so be thorough. We love our Lagoon 440 and have seen 440's with major lack of tabbing and lots of cracks like that and misalignment of things that would make your eyes water and they are still sailing along and able to be brought up to snuff to the point they are better than new.

But it IS dusty itchy work in tight places

Thanks very much for that information. I was wondering what real world experience with the 440 meant with these separations, and creaky furniture makes perfect sense!

[catsketcher]

Not having sailed on a 440 or 450 so no specific knowledge but the workmanship is not good.

Tabbing a structural element into a composite structure requires some simple rules to be followed - most important is to ensure that joins can take 100% of the loads given to the part. The tiny radius, single laminate and small overlap onto the hull surface is just bad building.

I get that owners are happy with the boats, but the fact that composite parts are failing after years of use means that these parts are being way overloaded beyond the build/design load taking ability. Most amateur cats I know would never have every had a single crack in structural parts. My 23 year old custom cat had one crack that I tidied up with uni in 1 hour. But custom cats are tabbed all over and I have rarely seen such small radius coves and small overlaps.

I can't understand how a composite cat can start breaking down tabbing unless all of the tabbing, even if has not failed is very much underbuilt. Even if none of the tabs have failed on a 440, then it may be well on its way to fatigue failure because it is too highly loaded. So I would seriously consider redoing the tabbing no matter what the condition of any particular cat that had sisterships with issues.


cheers

Phil

[GordMay]

“Tabbing Bulkheads to the Hull and Deck” ~ by Robert Klingberg
➥ https://www.kp44.org/ftp/TabbingBulk...l_and_Deck.pdf

See ➥ https://www.cruisersforum.com/forums...tc-190725.html

See also, from Post #3 ➥ https://www.cruisersforum.com/forums...ads-78432.html

[Tin Tin]

There are structural bulkheads (with several layers of glass on the joins (easy one to see is in the engine room) and then the bedding, furniture and joinery panels that are glued in with Plexus structural adhesive which accommodates flexing of the hull.
https://itwperformancepolymers.com/m...ational-marine

[Jenta]

Originally Posted by catsketcher

Not having sailed on a 440 or 450 so no specific knowledge but the workmanship is not good.

Tabbing a structural element into a composite structure requires some simple rules to be followed - most important is to ensure that joins can take 100% of the loads given to the part. The tiny radius, single laminate and small overlap onto the hull surface is just bad building.

I get that owners are happy with the boats, but the fact that composite parts are failing after years of use means that these parts are being way overloaded beyond the build/design load taking ability. Most amateur cats I know would never have every had a single crack in structural parts. My 23 year old custom cat had one crack that I tidied up with uni in 1 hour. But custom cats are tabbed all over and I have rarely seen such small radius coves and small overlaps.

Phil

That all makes sense, but this is an example of a location that was chosen by the manufacturer to NOT be laminated and instead some ?flexible? adhesive was used. It does appear that procedure was modified a bit during the 6 year production though none of them that I am aware of went all the way up the outside hull with lamination. One can certainly question why that decision was made in some locations of the boat, but these are the areas that many of us owners are repairing by removing the old adhesive and doing a proper lamination job as Gord had referenced.
Certainly I would have preferred them to have been manufactured that way from the beginning but I imagine labor is one of the biggest costs in building a boat and it is what it is. I think many things on a boat like this are engineered and designed to be made a certain way, and then changes are made to reduce costs and streamline building but still keep the final product sound.

Honestly if there was only 1 thing about how catamarans are built (I think most mid-tier production ones) it would be how they do the furniture. I would MUCH prefer that they put the hull together and then build the inside furniture and accessories and do it in such a way that it can be disassembled and reassembled. I don't care if it is a jigsaw puzzle so long as there is a process for removal and replacement. But instead we have assemblies that are dropped in prior to the deck being placed on with tabs, glue and screws in locations you can't possibly reach after assembly and your option is to cut it out and then figure out how to put it back the least ugly way possible.

Anyway - end rant

[catsketcher]

Gday Jenta

Good thoughts on price and time, it takes a lot of time to epoxy a cupboard or similar into a hull, cove it, glass the cove, then fill and fair it. Much simpler to increase the scantlings of the hull and not need the interior for structural integrity.

The pic has some tabbing on it, which is where my comments came from. It is different from custom cats. On mine, and most other custom cats, almost ever interior panel is structural in some way, connected to the hull with epoxy and glass. I have no structural parts that end anywhere but a beam. All the horizontal members end at a bulkhead. Cupboards and small bulkheads end at the floor pan members or the table tops that can take the loads again to the bulkheads. The pic shows a panel just ending, I can't see how its loads get fed into another panel at 90s degrees or how the tip won't have problems if the hull side gets deflected, which is my guess as to why it failed.

[sycheckmate]

Check "similar threads" at the bottom of this page. Also Utube "Sailing Parlay Revival" for a well documented purchase of a hurricane damaged 450 and bulkhead issues