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Old 29-01-2015, 10:23   #1
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Boats coming apart at the toerail...

So, this months Sail Mag has an article about a Pearson that was rolled at sea and the side caved in coming completely apart at the hull deck joint... the picture shows the hull caved well in from the deck edge. They survived barely. Not a hurricane or huge storm etc.
This is the third of this type of damage I've heard about over the years, not counting Rebel heart... which may have been a different build construction/situation... unsure. All the boats in question were old. I think most of us believe the Pearsons to be fairly well built boats, not a Westsail, but not a light boat either.
I'm one of those people who believe "where there's smoke there's fire".. so here's the question.
I wonder how badly fiberglass "ages", gets more brittle etc, to the point where it looses a lot of strength?
Thinking about it, I've salvaged a couple old dingys that sat outside unused for a long time, turns out they were so brittle, that the cloth seemed to have less resin and you could easily put your foot right thru the hull.
I wonder if anyone has ever done strength testing on old fiberglass panels vs new of the same layup?
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Old 29-01-2015, 10:31   #2
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Re: Boats coming apart at the toerail...

Fibreglass doesn't age as such. That being said it's time to put our propellor caps on.

Any composite is composed of a matrix (fibreglass in this case) and something to fill all the voids and mechanically key the matrix as a single homogeneous unit. (Resin)

Failure modes include physical (abrasion, impacts, fatigue, thermal, erosion and overload and chemical (UV, chemical attack, etc).

So to answer this question we need to answer some questions.

Was the failure of the resin matrix itself or the joint? You mentioned failure at the toe rail. Is it screwd, bolted, bond3d or glassed together.

Finally any delamination failure will usually be traced to a manufacturing defect. This is not a failure of the composite but a quality issue.

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Old 29-01-2015, 10:45   #3
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Re: Boats coming apart at the toerail...

Some boats were built with a hull-deck joint just glassed in, no mechanical fastenings. Not sure if this was the case with the Pearson.
This has to be one of the most vulnerable parts of the boat, as due to the hull flexing one way and the deck the other way, must put a lot of stress on the joint. A laminate without the added assistance of a mechanical attachment, one day something will give.
Hull to deck joints are notorious for leaks, which to me is the first indication of big trouble ahead - water intrusion, delamination plus SS corrosion and eventually separation.
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Old 29-01-2015, 10:49   #4
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Re: Boats coming apart at the toerail...

Done correctly, a glassed joint will form a monocoque and be much more reliable, stiffer and rugged than a mechanically attached joint, let alone never leak.

A hull caving in sounds like a bulkhead came detached.

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Old 29-01-2015, 10:51   #5
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Re: Boats coming apart at the toerail...

It was a Pearson 28 Triton. There appears to be bolts still in the picture, appears the fiberglass simply ripped leaving the wooden toerail intact. The hull is caved in permanently maybe a foot I would say. Access to the V berth was closed up as the bulkhead was shoved in so far it blocked the doorway. They were trying to sail from Panama to Bonaire I think. Rolled by a large wave amongst smaller ones. That's a rough go...
Maybe someone knows how these boats were built... glassed as well as bolted?
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Old 29-01-2015, 10:53   #6
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Re: Boats coming apart at the toerail...

No toerails on a Manta. Do any of the older cats have toerails?

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Old 29-01-2015, 11:01   #7
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Re: Boats coming apart at the toerail...

I've been told by my boatbuilder friend that the sunlight is the biggest enemy of fiberglass. But that is rectified by adding special additives to the resin mix prior to layup. He calls them jokingly "Florida additives" meaning you need even stronger mix for boats destined to southern climes. So it is very possible that the Pearson in question was built in the 70s and not destined to equator area use and thus had very little of that protection addded. And if subsequently it was mostly used in the South and thus probably year round there you have a perfect storm coalescing together.

My same friend tells me that if one buries a well built fiberglass hull in the ground and digs it out hundreds of years later it should be OK to be used. Provided of course there are no chemical or other industrial spills nearby or any prolonged exposure to the sun.
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Old 29-01-2015, 11:07   #8
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Re: Boats coming apart at the toerail...

Fiberglass loses a lot of strength through cycle fatigue. A excellent describtion and lab tested results are in the Gougeon Boatbuilding book available as a free download from the WEST epoxy site. Chapter 3 "Wood as a Structural Material" has these figures graphed for wood, steel, aluminum and glass and carbon. Briefly after a million cycles, accrued over about 4 years of weekend use and cruising, wood has 60% of its strength left, aluminum 40% and glass 20%.
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Old 29-01-2015, 11:10   #9
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Re: Boats coming apart at the toerail...

Quote:
Originally Posted by Cheechako View Post
So, this months Sail Mag has an article about a Pearson that was rolled at sea and the side caved in coming completely apart at the hull deck joint... the picture shows the hull caved well in from the deck edge. They survived barely. Not a hurricane or huge storm etc.
This is the third of this type of damage I've heard about over the years, not counting Rebel heart... which may have been a different build construction/situation... unsure. All the boats in question were old. I think most of us believe the Pearsons to be fairly well built boats, not a Westsail, but not a light boat either.
I'm one of those people who believe "where there's smoke there's fire".. so here's the question.
I wonder how badly fiberglass "ages", gets more brittle etc, to the point where it looses a lot of strength?
Thinking about it, I've salvaged a couple old dingys that sat outside unused for a long time, turns out they were so brittle, that the cloth seemed to have less resin and you could easily put your foot right thru the hull.
I wonder if anyone has ever done strength testing on old fiberglass panels vs new of the same layup?
I have seen that "kick a hole thru it" with chopper gun built dinks & other f-glas products.
So far,not with hand laid solid hulls.
Cored decks are iffy,when the core disintegrates from water-rot,so I do wonder about cored hulls,in the long term,if they are subject to water intrusion.
Hulls that are built in 2 halves,& properly joined by hand laid methods seem OK also.
Weren't most hull & deck joints just set in the sealant of the day & bolted?
That would suggest that,most sealants being "flexible gaskets",as opposed to a resin based glue,the joint could flex over time,especially if squeezed,etc.
That leaves the bolts,& I do know that a bolt in a flexing f-glas joint,will quickly enlarge the hole.
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Old 29-01-2015, 11:12   #10
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Re: Boats coming apart at the toerail...

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Fibreglass doesn't age as such.
I think this is a common misconception. A polyester resin layup immersed in water certainly loses significant strength with time. Any cycle loading will produce additional losses.
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Old 29-01-2015, 11:20   #11
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Re: Boats coming apart at the toerail...

Quote:
Originally Posted by RTB View Post
No toerails on a Manta. Do any of the older cats have toerails?

Ralph
that's too bad... the toerail is all that stayed intact!
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Old 29-01-2015, 12:04   #12
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Re: Boats coming apart at the toerail...

Quote:
Originally Posted by RTB View Post
No toerails on a Manta. Do any of the older cats have toerails?

Ralph
Ours must be a special build because we certainly have toerails.

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Old 29-01-2015, 13:24   #13
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Re: Boats coming apart at the toerail...

I read the description written by the owner of the Pearson Triton of what happened during the incident that left his boat essentially destroyed.

The owner described having passed by a river delta where much debris was seen in the water. Tree trunks, branches and much man made stuff was seen floating around. It was only a short time later, during heavy weather, that the boat suffered the damage. It appears from the pushed in section of the hull that the boat made have struck something which could very well have caused the damage seen in the photo.

Late last year my 1962 Pearson Triton broke loose from her mooring and ended up on a rock beach. She pounded on that beach during heavy surf for at least 8 hours before she was lifted off. The damage was located in the same area, just below the chainplates, only at the waterline, not the hull/deck connection. She suffered no more damage than some chipped gel coat.

The boats were built like brick shithouses. I vote that the boat hit an object at or near the surface during heavy weather.
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Old 29-01-2015, 14:12   #14
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Re: Boats coming apart at the toerail...

Fiberglass definitely does degrade with age. This is well established engineering knowledge. It is not an opinion. Factors that degrade fiberglass include:
1. Stress. This is a big one. As referenced above, the Gougeon Bros did extensive, scientific testing of fiberglass laminates using cyclic load testing equipment that, as I recall, was funded by NASA. They found that polyester resin fiberglass fatigues significantly, due to microcracking between the weak polyester resin and the strong glass fibers. This is why old glass dinghys get "soft". Their report is well worth reading.
2. Hydrolysis. Water does, over time, degrade and weaken the resin matrix. How much and how fast can be very variable, it depends on the resin type, how well it was catalyzed, barrier coating, etc. It can be minimized, it cannot be eliminated.
3. UV. UV will destroy most plastics, this includes polyester and epoxy resins. If it is fully blocked by adequate gel coat, paint, etc this can be eliminated or greatly reduced. Without sufficient blocking it can greatly weaken the resin pretty quickly.

The biggest joker in fiberglass reliability is that fiberglass is not a constant, consistent material. It is made by the people that built the boat. Did they use the correct resin? Catalyze it properly? Wet out the glass fully? Work out all the air bubbles? Work out all the excess resin? Apply the next lamination before the first had fully cured? Apply the correct number of laminations? With the correct orientation?

No one knows. Laminating glass is not a high paying job. The aerospace industry uses composites and goes to great lengths to ensure quality control is high. They do a good job and their parts are very expensive.

If metal was like fiberglass every builder would be smelting ore, alloying the melt, pouring his ingots and rolling his plate. That metal would be a lot less reliable than what is produced by a 100 million dollar steel plant.
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Old 29-01-2015, 14:42   #15
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Re: Boats coming apart at the toerail...

Discovered a little manufacturing screw up on the hull of my 40 year old Pearson 35. Boat had been sailed in SF Bay most of its life which has plenty of strong winds and chop without any issues becoming apparent. Had a problem with the self steering vane which showed under catalyzed layup at the turn of the hull at the cap rail in the transom. Began probing out ward from initial spot and found the turn of the deck virtually laid up with no resin around the entire hull. Pearson laid up a not very robust lamination on the inside of the hull and deck which was the only thing really holding the hull and deck together.

Used a chisel to tear out the bad laminate all around and then ground a taper all round and laminated the hull to the deck. Stronger than new and no more leaks on the hull to deck joint. Probably would have been money ahead to scrap the boat for the lead and fittings but I'm kind of fond of the old girl.
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