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Old 12-24-2014, 01:56 AM   #21
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AKDoug,
This is a random core sample of the underwater area.
The local marine board wanted to see if this vessel meets their standards.
As you can see the sample was made up of 44% glass content,they have a minimun of 40% to allow commercial operation.
Bluetide.
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Old 12-24-2014, 09:57 AM   #22
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The core test is simply a matter of burning off (hence the reference to crucible temperatures) the resin in order to determine the resin/glass ratio and to enable peeling apart of the glass layers to determine the laminate schedule.

Older FRP boats tended (not in this case) to have a much higher resin content as the process was somewhat primitive (Bill & Bob with a bucket of resin and a roll of glass). 60's / 70's production boats may have had as much as 70% resin content while newer processes result in about 50/50 laminates although this too can vary depending on the type of cloth used.

Later (1980's) engineering studies showed that a much lower resin content was actually stronger. By that time the various infusion processes were coming into play which allowed much more control of this ratio than Bill & Bob were capable of.
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Old 12-24-2014, 02:44 PM   #23
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boatpoker,
Wow,well said.
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Old 12-26-2014, 07:27 AM   #24
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The core sample was required to assure the licensing folks the boat was built with Fire Retardant resin , not cheaper yacht resin.

In the US this is required for a boat to carry more than a minimum number.

A >6 Pack< boat could be of cardboard that dissolves when wet but with the proper gear , fire ext and vests , it gets an OK.

If you wish to carry more folks the FR resin is required. Further up in the pax count gets to Sub chapter T , collision bulkhead , inclining test afloat with weight and better bilge pumping are part of the deal.

The laminate sked simply shows it is a military build ,. WR is woven roving .

The military has the bucks to require a large lay up crew and have the basic hull done in one work session.

Less expensive yachts will have WR CSM WR CSM layup (chopped strand mat) as a small crew can do the boat over a day or two. CSM also adds thickness cheaper than WR.

The WR/WR is far more tolerant of damage than the WR/CSM layup, but then bulldozing a Utility off a sinking carrier deck is part of the carriers abandon ship drill , that yachts seldom contemplate.
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Old 12-26-2014, 08:11 AM   #25
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Quote:
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The core sample was required to assure the licensing folks the boat was built with Fire Retardant resin , not cheaper yacht resin.

In the US this is required for a boat to carry more than a minimum number.

A >6 Pack< boat could be of cardboard that dissolves when wet but with the proper gear , fire ext and vests , it gets an OK.

If you wish to carry more folks the FR resin is required. Further up in the pax count gets to Sub chapter T , collision bulkhead , inclining test afloat with weight and better bilge pumping are part of the deal.

The laminate sked simply shows it is a military build ,. WR is woven roving .

The military has the bucks to require a large lay up crew and have the basic hull done in one work session.

Less expensive yachts will have WR CSM WR CSM layup (chopped strand mat) as a small crew can do the boat over a day or two. CSM also adds thickness cheaper than WR.

The WR/WR is far more tolerant of damage than the WR/CSM layup, but then bulldozing a Utility off a sinking carrier deck is part of the carriers abandon ship drill , that yachts seldom contemplate.
I keep a copy of the relevant Code of Federal Regulations and The American Bureau of Shipping Standards on my desk. I also have all of the US Mil specs for "Reinforced Plastic Vessels" There is nothing in any of them that I can find with the requirements you state. Can you please provide the legal references for the commercial use requirements.
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Old 12-26-2014, 08:51 AM   #26
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Just go to the US CG site for inspected vessels , or to Sub T section for all of the rules.

My computer server runs at dial up speeds , or I would do it for you.
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Old 12-26-2014, 09:00 AM   #27
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Just go to the US CG site for inspected vessels , or to Sub T section for all of the rules.

My computer server runs at dial up speeds , or I would do it for you.
Thanks, I'll take a look. I am not very familiar with US commercial vessel requirements but always interested to learn more.
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Old 12-26-2014, 12:42 PM   #28
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If you stop in at one of the US CG offices they will hand you a pretty comprehensive book, free.

Just tell them you want to build a boat to carry ,say, 16 folks for hire.

Might even send it to a US address with a phone call?
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Old 12-26-2014, 12:51 PM   #29
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If you stop in at one of the US CG offices they will hand you a pretty comprehensive book, free.

Just tell them you want to build a boat to carry ,say, 16 folks for hire.

Might even send it to a US address with a phone call?
I found fire retardant specs for insulation, paint, floor finishes, deck finishes and non-load bearing interior partitions but I can't find anything on hull laminate schedules or fire retardant resins.

I am particularly interested in specs for the laminate schedule because neither US Mil. specs, CE, Det Norske Veritas, American Bureau of Shipping nor ABYC have ever been able to come up with a spec for that due to the infinite number of variables. Even the US Mil spec specifies only results for laminate testing and do not rule out the use of CSM.

I am also interested in the spec for fire retardant resins as all i know about those is that they caused the huge blister issue for Uniflyte which caused the demise of that company.
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Old 12-26-2014, 02:55 PM   #30
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In case you don't already have them, here are a couple of publications you might find helpful relating to USCG and Mil. Spec. for fire retardancy.

NAVIGATION AND VESSEL INSPECTION CIRCULAR NO. 8-87 With Change 1
Enclosure (1) to NVIC 8-87
NOTES ON DESIGN, CONSTRUCTION, INSPECTION AND REPAIR OF FIBER REINFORCED PLASTIC VESSELS
https://www.uscg.mil/d13/cfvs/PDFs/nvic8-87.pdf
Chapter 1., Part F, 1. & 2.

Military Specification (Milspec) Mil-R-21607
Guideline for the Approval of Laminating Resin for Fiber-Reinforced Composites Used in Life-saving Equipment and Small Passenger Vessels
Fire Retardant Resin
https://www.uscg.mil/hq/cg5/cg5214/d...in%20Guide.pdf

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Old 12-26-2014, 03:43 PM   #31
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Thanks Larry, that was interesting reading. They take the same approach as the ship building societies and other standards authorities in that they don't say you must use this or that but lay out the tests that the products must pass. The only place they specify fiber types is for making up test panels to test resin otherwise fiber specs are left pretty open. This is understandable given the thousands of fiber patterns (woven or chopped) and materials (not just glass anymore) on the market.

Up here in the Great White North I don't get involved with US commercial stuff but I am always looking to learn.
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Old 12-27-2014, 07:25 AM   #32
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The basic concept is an oak hull has a burn rate of about 100.

Std. GRP has a burn rate of 500 .

The US Coasties require a FR resin to bring the burn rate back to 100.

With special additives the burn rate can be brought down to under 10, self extinguishing , usually done for factory ducting.

The additives will reduce the hull strength by 2-5% , easily compensated for in a structure that is about 400% overbuilt to reduce flexing.

Interesting early LLoyds GRP rules are for an ALL CSM boat , the hull thickness can then reduced for selecting better materials .
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Old 04-18-2015, 11:58 PM   #33
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New question here. I am getting water down through one of the cleats mounted on the cap rail (port side midships) and wondered if the cap rail was cored? I am expecting not, since there would be no point in doing so. One more leak to chase down before launching this year, it's been leaking for a while but now is the time to get it handled.
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Old 04-21-2015, 06:39 AM   #34
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A burn off test for an ex military boat , is mostly to make sure the hull is made with FR (fire retarding) resin.

UP to 6 pax a cardboard box with the USCG required items can go into business.

But to carry more folks the FR is a requirement .

For Subchapter T there are other requirements. Collision bulkhead ,,,

NONE of this ex military construction has much to do with a pleasure boat.

Willard has a great rep as a boat builder , your "surveyor"?

Don't worry , be happy , and forget about another "surveyor" attempting to justify his fees.
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