Has anyone sunk from deck delamination?

[JPA Cate]

This is a somewhat different viewpoint on this issue, but if you are a responsible boat owner, and you know the boat has a rot problem, why would you not fix it if it is accessible? Simply injecting epoxy to tie the surfaces together is not all that difficult. Jim's repaired a wet balsa place by the two chainplate penetrations on our previous boat, by scooping out the wet balsa core with a bent teaspoon, then filling with epoxy and colloidal silica mix. It worked well, and we never had a leak there again while we owned the boat.

Ann

[LittleWing77]

Originally Posted by CassidyNZ

There is a recorded event near NZ where a boat was lost due to largish windows popping out. Since the boat was irretrievably lost, it hasn’t been determined that the windows popped out due to some structural malfunction.

Was it a localised delamination? Who knows?

It's always dismayed me the increasing trend towards large, long "windows" instead of proper portholes. If anyone would like a gripping read, Albatross by Deborah Scaling Kiley https://m.alibris.com/Albatross-Debo...928?matches=11 is about a wave stoving in such windows. The boat filled and sank in just over 2 minutes - their liferaft blew away in the extreme winds and they managed to survive in the inflatable dinghy (some of them) until they were picked up.

I feel like the root of your question, Creedance, goes to the bluewater boat debate: if you were sailing offshore in oceans, the delaminated core would be a concern, as it feeds into the structural integrity of the boat. If you were lake-sailing here in Lake Ontario where nobody goes out in much more than 15 knots of breeze, not so much.

Fair Winds,
LittleWing77

[valhalla360]

Unless it's excessive or localized around critical structural components (say chain plates), it would be such an unusual way for a boat to go down, that it's not worth worrying over.

So yes, try to stay ahead of it, reseal and replace core when possible don't get too obsessive about it if it's just a few small spots.

[Creedence]

I guess localized failure around deck hardware could be the more legitimate concern. I could see a windlass or winch possibly cracking its way up and out. So I’m beginning to feel it’s an unlikely risk to fundamental seaworthiness, but could result in actual damage in some circumstances.

For my part, I’ll keep lining the holes in the deck with epoxy as I tackle the many leaks ol’ girl has. I don’t think the skin removal and core replacement is in my future.

[Cheechako]

Boats coming apart at the toerail have occurred multiple times in my memory. Likely due to poor glass resin ratio or poor layup schedule. But I have not heard of a delamination issue causing a major event.

[Chotu]

Originally Posted by LittleWing77

It's always dismayed me the increasing trend towards large, long "windows" instead of proper portholes. If anyone would like a gripping read, Albatross by Deborah Scaling Kiley https://m.alibris.com/Albatross-Debo...928?matches=11 is about a wave stoving in such windows. The boat filled and sank in just over 2 minutes - their liferaft blew away in the extreme winds and they managed to survive in the inflatable dinghy (some of them) until they were picked up.

I feel like the root of your question, Creedance, goes to the bluewater boat debate: if you were sailing offshore in oceans, the delaminated core would be a concern, as it feeds into the structural integrity of the boat. If you were lake-sailing here in Lake Ontario where nobody goes out in much more than 15 knots of breeze, not so much.

Fair Winds,
LittleWing77

Theoretically speaking, if the large windows are Lexan, they could be as resistant to stoving in from a wave crash as the hull itself, no?

Certainly glass or plexiglass doesn’t offer the same strength, but there are ways to have large windows and have them be structural.

This is my personal philosophy. What do you think?

[Cheechako]

Originally Posted by Chotu

Theoretically speaking, if the large windows are Lexan, they could be as resistant to stoving in from a wave crash as the hull itself, no?

Certainly glass or plexiglass doesn’t offer the same strength, but there are ways to have large windows and have them be structural.
This is my personal philosophy. What do you think?

Probably so, if they are actually bonded or bolted to the boat. The problem with many older large boat windows is they are installed with aluminum trim in a rubber gasket like a car windshield was in the old days. They can pop right out with a big wave. Not to mention they were not real thick plastic either.
There's a name for that rubber installation system that evades me right now.

I was involved with some small aluminum military boats that had that system and a large window in front. In testing, while purposely hitting a big wave it popped right out causing injury to the driver.

[Tetepare]

I'd have to say "probably". Best I can do.


Some real-world observations:


1. Boat neighbor bought a windlass. Upon installation discovered that the core was gone, so he had to recore. If he had installed, or if a windlass had been previously installed and the core was gone, could lead to catastrophic anchorage issue.


2. Looked at a production boat that the core was completely gone under a baby stay thru-deck fitting. The "core" had compressed to nothing, cracking the liner badly, and the deck was raised 1/2" in that area. I dunno- I like all my stays to be operating at top efficiency.


3. Multiple wet cores that rotted the bulkheads onto which chain plates were attached. Bad juju.


4. Not catastrophic, but....we looked at a semi-custom with the most fabulous layout. It had been neglected for a long time. Inside, streams of water RAN down the inside of the hull from the deck- and it had not rained for two weeks, nor had they washed the boat. The deck must have been fully saturated. I thought it was a catastrophe waiting to happen.

[a64pilot]

Originally Posted by Chotu

Theoretically speaking, if the large windows are Lexan, they could be as resistant to stoving in from a wave crash as the hull itself, no?

Certainly glass or plexiglass doesn’t offer the same strength, but there are ways to have large windows and have them be structural.

This is my personal philosophy. What do you think?

Lexan is very tough and hard to break, largely because it’s so soft and flexible, soft and flexible isn’t the types of materials that stand up to a breaking wave.

My Portlights are thick heavy SS frames, the glass is laminated safety glasses like an auto windshield, if I had large windows I’d want something similar as opposed to Lexan.

How are the Motor Life boat windows constructed?

[Manateeman]

Actually never seen one sunk. I’ve seen the mast fall down, the cleats ripped off, the hatch ripped off, the stancheons bent over, one davit and dinghy gone, a steering failure...all no big deal considering some people get use to sleeping in a wet bunk.
Just don’t ask a USCG passenger vessel inspector to overlook wet core. As this is an International forum, I shall hope others will add comments to their national standards on vessel construction and inspection.
I know of a case in Hawaii where wet hull core combined with a lightning strike did blow a rather nice size piece of the hull apart.
Sailing around with any moisture inside the structural elements of your vessel ?
Why confine the question to sinking. What about no mast or no lifelines, no steering, loose motor, nice big lightning holes.
I’ve heard of sponge pants bob. Maybe there is a sponge boat for Ken, Barbie and fluffy the cat. And no, I don’t want the cat wet either.
Happy trails to you.
Captain mark and his high moisture meter reading manatees

[bauer965]

Here's one of the largest concerns with the deck issues mentioned above. First, remember, the point of the core is to create a laminate that has a certain stiffness. That stiffness an an engineered element of the vessel, and in is concert with your rig, the rig tension and associated transfer of loads to and through the hull. Core deterioration, depending on extent and location, will result in a reduction of deck stiffness. When this happens, the hull will flex more than it did before the core delamination, which was originally, not very much. Now, every time the boat slams into head seas (or even rides up and over them), the hull is flexing (more than usual), loading up the rig, over and over, greater stresses, unnecessary fatigue, etc.. So in a nutshell, the longevity of your rig components are shortened with these increased stresses. Only your sailing frequency/environment will determine whether this is a factor for you.
Loads are of course transferred the other way as well: increased rig loads, for whatever reason whether static or cyclical, will flex the hull more than "normal". Do this a million times, and the deck will eventually protest. Possibly causing issues like that which caused the delamination in the first place, hence creating a self-fulfilling cycle.


So yes, many things could go wrong on the ocean, of which you are responsible for, which could cause the boat to sink. If full forensic evidence was available in these cases, one may be able to deduce that the root cause was hull delamination, although over-stressed rig components may have been the primary contributing factor.

[Cheechako]

Originally Posted by bauer965

Here's one of the largest concerns with the deck issues mentioned above. First, remember, the point of the core is to create a laminate that has a certain stiffness. That stiffness an an engineered element of the vessel, and in is concert with your rig, the rig tension and associated transfer of loads to and through the hull. Core deterioration, depending on extent and location, will result in a reduction of deck stiffness. When this happens, the hull will flex more than it did before the core delamination, which was originally, not very much. Now, every time the boat slams into head seas (or even rides up and over them), the hull is flexing (more than usual), loading up the rig, over and over, greater stresses, unnecessary fatigue, etc.. So in a nutshell, the longevity of your rig components are shortened with these increased stresses. Only your sailing frequency/environment will determine whether this is a factor for you.
Loads are of course transferred the other way as well: increased rig loads, for whatever reason whether static or cyclical, will flex the hull more than "normal". Do this a million times, and the deck will eventually protest. Possibly causing issues like that which caused the delamination in the first place, hence creating a self-fulfilling cycle.


So yes, many things could go wrong on the ocean, of which you are responsible for, which could cause the boat to sink. If full forensic evidence was available in these cases, one may be able to deduce that the root cause was hull delamination, although over-stressed rig components may have been the primary contributing factor.

Yes, the deck is designed as a "beam" to be rigid. I often wonder though if it's more to keep from flexing when walked on than hull support?. Early fiberglass boats had solid decks and people complained they flexed when walked on. If a boat has enough good bulkheads the hull is stiff and cant flex badly. The rig wants to pull the hull narrower while boats flex and twist at sea. 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! :>)

[bauer965]

I can't answer those questions without looking at the construction details of any given vessel of interest. The light scantlings of many vessels of the type appropriately to this forum, would rely on the deck to provide some moment of inertia.

[Lionshooter]

Originally Posted by LittleWing77

It's always dismayed me the increasing trend towards large, long "windows" instead of proper portholes. If anyone would like a gripping read, Albatross by Deborah Scaling Kiley https://m.alibris.com/Albatross-Debo...928?matches=11 is about a wave stoving in such windows. The boat filled and sank in just over 2 minutes - their liferaft blew away in the extreme winds and they managed to survive in the inflatable dinghy (some of them) until they were picked up.

Fair Winds,
LittleWing77

A tad off-topic but interesting to me that you mentioned the fate of the Albatross because I too was in that same storm approximately 30 miles south of the Albatross. We had been in radio communication while I was fighting for my life in my 23' sloop. 5 sailors on the two boats that went under lost their lives. My "toy" boat survived.

[LittleWing77]

Originally Posted by Lionshooter

A tad off-topic but interesting to me that you mentioned the fate of the Albatross because I too was in that same storm approximately 30 miles south of the Albatross. We had been in radio communication while I was fighting for my life in my 23' sloop. 5 sailors on the two boats that went under lost their lives. My "toy" boat survived.

Wow. Just wow.

I wanna have a beer with you someday, Lionshooter!

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