Has anyone sunk from deck delamination?

[Singularity]

Originally Posted by Cheechako

...A rigid deck will help with that, but how much is needed if the bulkheads are plenty and good?

If a boat has 3/4" teak screwed securely to a wet core deck, is it stronger than a dry fiberglass deck? Probably! :>)

With composite construction things are typically 'strong enough' long before they are 'stiff enough.' Lots of transverse/athwartship bulkheads don't lend to torsional rigidity anywhere near that which a surface skin (e.g. deck) provides.

If the dry all-fiberglass deck is flexes...and the designer accounted for that flexing in design, then the flexing of an all-glass deck isn't a problem (other than for paint issues). Think monocoque construction, like the aluminum skin on a small Cessna wing. The aluminum skin on the Cessna wing eliminates the need for underlying diagonal trusses of the wings of yesteryear, while the skin is remarkable thin. You can crease it with your fingernail and you for sure can't stand on it without grossly deforming it.

Agree with Baeur's point though. Once stiffness goes, then everything starts to dis-assemble itself all over the place in response to successive load cycles. Maybe no problem for coastal work, but beyond that, who knows.

[taxwizz]

Originally Posted by Creedence

I’ll close by waving my underwear at everyone as a peace offering. I’m just looking for an enlightening discussion.

PINK underwear ?
Just wondering.............

[Manateeman]

Captain new to the land or jack london. First, I don’t know how you can fasten anything to wet core. Even if you bolt with plates on both sides, there is little strength. I worked for a large OEM builder who was one of the first larger names to use balsa core. The built a lot of boats and repaired a lot under warranty.
Core construction relies on three things. The integrity of the core, the strength of the bond between core and panel, and the absence of water. Even with a plastic core, water could freeze or expand and destroy the bond between core and panel.
Slapping some kind of band aid on is not a solution. Core boats require engineering to produce and skilled boatbuilding to repair.
I was asked to look at a vessel which had been rejected for COI twice. A very young USCG inspector did both inspections. A cat with hull core wet and filled in some sections with diesel. The first rejection was by the book. The owner was furious at her and then hired the cheapest crew to do the repair. Not only not properly documented, but a real hack job which simply wasted everyone’s time.
It is extremely difficult to repair critical areas in a cored boat. You must understand all the forces, and how the architect resolved them. You have to be skilled in technique and knowledgeable in materials. You can easily construct a bad repair...a hard spot or too flexible and the higher tech the boat, the more expertise is needed. DIY is possible but I’ve seen failures as well. Do you want to be in a position where you have to ask others to risk their lives so you could save money. If you ask them how to properly do a repair, or where they might learn, I’m sure they would help you. I thought proper seamanship was one of the aims of the interchange of ideas on the forum. Wet core is dangerous and I’ll stand on that statement. But it’s your boat so...
Happy trails to you.
Mark and his frolicking manatees

[barnakiel]

PINK UNDERWEAR ???


PM sent darling!


;-)
barnakiel

[taxwizz]

Originally Posted by barnakiel

PINK UNDERWEAR ???

PM sent darling!
;-)
barnakiel

Awwww Geeeee.
You are making me blush, honey.

[Creedence]

Originally Posted by Manateeman

Captain new to the land or jack london. First, I don’t know how you can fasten anything to wet core. Even if you bolt with plates on both sides, there is little strength. I worked for a large OEM builder who was one of the first larger names to use balsa core. The built a lot of boats and repaired a lot under warranty.
Core construction relies on three things. The integrity of the core, the strength of the bond between core and panel, and the absence of water. Even with a plastic core, water could freeze or expand and destroy the bond between core and panel.
Slapping some kind of band aid on is not a solution. Core boats require engineering to produce and skilled boatbuilding to repair.
I was asked to look at a vessel which had been rejected for COI twice. A very young USCG inspector did both inspections. A cat with hull core wet and filled in some sections with diesel. The first rejection was by the book. The owner was furious at her and then hired the cheapest crew to do the repair. Not only not properly documented, but a real hack job which simply wasted everyone’s time.
It is extremely difficult to repair critical areas in a cored boat. You must understand all the forces, and how the architect resolved them. You have to be skilled in technique and knowledgeable in materials. You can easily construct a bad repair...a hard spot or too flexible and the higher tech the boat, the more expertise is needed. DIY is possible but I’ve seen failures as well. Do you want to be in a position where you have to ask others to risk their lives so you could save money. If you ask them how to properly do a repair, or where they might learn, I’m sure they would help you. I thought proper seamanship was one of the aims of the interchange of ideas on the forum. Wet core is dangerous and I’ll stand on that statement. But it’s your boat so...
Happy trails to you.
Mark and his frolicking manatees

Manatee. I’m not sure if this is directed at me, but if it is, you’re missing the point of the thread. It’s not a discussion to talk me into of out of repairs. While I’m working on some related issues with leaking hardware, I thought I’d invite a discussion about the possible severity of deck delamination. So your well wishes and oddly defensive tone aren’t really necessary in this thread.

Your other points though are interesting and certainly seem valid. But the distinction I want to highlight here is that I’m asking about deck delamination, not hull. I recognize that is a related but very different animal. I’m sure we could find people who have lost a boat due to hull delamination.

More underwear for Manatee:

[Lionshooter]

Originally Posted by LittleWing77

Wow. Just wow.

I wanna have a beer with you someday, Lionshooter!

(Just no guns, please - I'm Canadian) LittleWing77

Anytime. I'll let you read the log from that ill-fated voyage. It's rather interesting. Cheers

[Creedence]

Originally Posted by taxwizz

PINK underwear ?
Just wondering.............

That’s for me to know and... wait, never mind.

[Manateeman]

One of the above posters was spot on. All the elements of the design work together. The original question was maybe a bit too specific. Delaminated core must be properly repaired because it might have already, or will eventually, result in the failure of another component of the vessel. If you loose your chainplates or your mast, you need not “sink” to need rescue. By sink I guess you mean submerged permanently. There are cases in which the skipper wished he had gone down with the ship. Example. You are the owner of a recreational boat and you have a soft deck near midship. Your guest grabs for a stancheon.
It fails and he’s overboard. You jibe, tack, whatever, and the deck pops or the chainplates rips out and the mast and everything is over the side as the MOB drifts away. The USCG calls it manifestly unsafe voyage because if anyone is hurt or killed, someone had to have known the boat was delaminating...coming apart.
Go back as far as the trial of the Bounty. Admiralty recommends hanging the innocent. Beat, keelhaul, up the yardarm till dead.
I’ve sat through a lot of maritime trials with my father. The insurance companies will try to settle without you. You will twist in the wind alone. But...
Happy trails to you kimosabi.
Captain mark and his off gassing manatees.
Don’t call them cows or dugongs. Please

[Creedence]

Fair point. So accepting that sinking from a failed, delaminated deck is a rarity, it might be interesting to try this:

Has anyone here experienced significant deck failure (i.e. winch or windlass cracking up out of the deck) due to delaminated decks?

[Bycrick]

Have I seen a failure of the deck? Yes.

One of the 41’ Taiwan boats the i worked on pulled the anchor windlass mounting right through the deck. Windlass mounted with 4 half-inch bolts. Interior backing plate was 1-1/2” plywood, with 4 fender washers. The water had gotten in and rotted both the core and the plywood. One night at anchor I’d SF bay, he pulled the windlass off the deck, taking a good chunk of the deck out underneath the windlass. When we cut out the top skin, we scooped out what was left of the plywood with a small dustpan. You could wrong water out of it with your hand. The bolts and washers tore apart the plywood backing plate and then the deck skins.

[Manateeman]

Yes. Please read post #25. The windlass stayed on the deck but the cleat and chain controller went over the side and the vessel lost her ground gear completely. Not a hurricane just a windy day.
If you loose your attachment for your anchor or worse, a forward hatch or a mast, you are only a few steps away from loosing the boat.
Delamination is a structural not cosmetic failure.
Just curious, why did you post this question.
Mark and his acetone huffing manatees.

[Creedence]

The question was not rhetorical. I thought it would be interesting to hear about any real-world catastrophic deck failures, not so deck rigidity could be debated, but so the thread could help people understand and assess the potential severity of deck delamination through actual experiences. It’s one thing to read “deck delamination is bad”, but quite another to hear first hand accounts.... And it makes for interesting conversation.

If you think about it, the thread seems to have at least generated a consensus that it’s not going to sink your boat, though in some circumstances it can be a contributing factor if other severe conditions exist.

But understand I have no opinion on the matter. I’m not making debate threads or anything. Just looking for interesting discourse.

[CMO Tashina]

The problem can get serious if the weak deck area sits under a sailboat mast. I just averted having my mast descend into the cabin below by having the deck opened up and the soggy wood core taken out and replaced with fiberglass.

[MikeFL]

Taking an integrated systems perspective of a boat with weak delaminated decks, it would certainly be possible that a running rigging anchor point, perhaps poorly backed to begin with, is ripped right out of a rotten deck leading to a catastrophic loss of the entire rig. Sort of like dominoes. Was the boat lost because of a rig failure or the rotten deck? I think Toss suggested to "follow the load".