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Old 28-05-2020, 14:49   #31
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Re: The loss of Kokopelli

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Originally Posted by a64pilot View Post
I have heard of more fires from flexible solar panels on Bimini’s than from gas generators.
This may be off topic, since we don't know the fire's cause, but I too have read of several fires caused by "flexible" panels mounted on biminis. I've inspected two such failures personally.

I put "flexible" in quotes because none of those panels will tolerate for long a mounting that causes them to continually flex or flog in the wind. They should be called "bendable" panels instead -- panels that can be bent once over a rigid cambered surface (like a cabin top) and never bent again.

The panel internal aluminium bonding wires won't tolerate continual flexing. Eventually the bending will exceed the bonding wire flex tolerance, a high-resistance crack will develop, and the panel output current will flow across that mechanical fault -- causing heat. The plastic laminated surface over that point can then combust. Result: fire, and if the bimini is nearby and combustible, the fire spreads.

The situation is made worse if multiple panels are wired in parallel. Then the fault current can be the combined sum of all of the parallel panel outputs caused by back-current flowing from the other panels into the fault-inhibited panel.

My advice is two points: One, if you are planning on mounting a "flexible" panel on anything other than a rigid non-flexible surface: don't. Two: if you have multiple panels wired in parallel: path each panel output through a Schottky diode to prevent combined back-current flowing into any of the panels. The loss through a good Schottky diode is very small (about 0.4 volts), they are cheap, and the prevention of back-current may in fact improve performance when one panel is shadowed.
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Old 28-05-2020, 14:55   #32
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Re: The loss of Kokopelli

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My advice is two points: One, if you are planning on mounting a "flexible" panel on anything other than a rigid non-flexible surface: don't.
Good to know, thanks, but I still feel that mine are acceptable. Mine are sewn and lashed to a very stiff bimini that is stretched between a solid gallows and a flexible but solid dodger (I plan a solid dodger at some point)
They are connected by over sized cable to a junction box with oversized buses and then to another oversized cable. And they stay there, I don;t move them around.
In light of your info I still think my system is ok. But I will more seriously consider a solid bimini in future.
Edit - I designed the bimini to allow for incremental stretching and tightening across the whole section over time, without creating loose panels.
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Old 28-05-2020, 15:03   #33
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Re: The loss of Kokopelli

My condolences to the couple. Very impressive display of abandon ship procedures I might add. Well done.
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Old 28-05-2020, 15:06   #34
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Re: The loss of Kokopelli

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Fires triggered by a fuel leak aren't all that common, but when they do happen, they tend to go from zero to really bad very quickly. Electrical fires tend to start a little more slowly before they reach the point where the spread becomes rapid.

This.

I once experienced a small electrical fire started by stupid PO wiring (he stuffed a twisted wire connection under carpet--I did a lot of checking after that). It was trivial to put out... because we were right there.

Fuel involved, yes, you are probably over your head immediately. That seems to be the case here.

But consider this. They were near shore. We were off-shore, well away from any help, anytime soon. Do you really want to jump in the water? Is the water cold? Do you have a raft? Do you think those odds are really good, or just so-so? They had no choice. We jumped right to it, found it, and put it out. Totally different situations.

Just sayin', the "call 911 and leave the house" guidance isn't always a great fit. This whole topic is also something to remember when you are doing wiring or engine work; do it right.
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Old 29-05-2020, 03:11   #35
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Re: The loss of Kokopelli

Do many skippers have fireports fitted


https://www.vetus.com/en/engines-and...hing-ring.html
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Old 29-05-2020, 03:36   #36
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Re: The loss of Kokopelli

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Do many skippers have fireports fitted


https://www.vetus.com/en/engines-and...hing-ring.html
No, although I have been thinking along the lines of sealing the engine room in a way that i can contain fires while still providing air when needed. But I only ever use the engine when it is absolutely needed, so an engine fire is not something that worries me too much.

Edit - I read in the case of the FPV Galaxy that burnt up in Alaska that the engine room vents could be closed to control fires (although they weren't in that case - great report though, thoroughly recommend)
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Old 29-05-2020, 04:02   #37
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Re: The loss of Kokopelli

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I have never seen a “generator compartment” for a portable gas generator.
SV Delos has one I think. I am not disputing that it is rare on recreational boats, I just think it is a bad idea to not have one.
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Old 29-05-2020, 04:26   #38
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Re: The loss of Kokopelli

First my compliments on a calm and orderly handling of an emergency. When the mayday didn’t work, they called the marina!

Second, this is good lesson for ALL owners. While fire ports are nice, they only give you a few moments of fire fighting (as long as extinguishers) and can only spray a small section of the engine area. Whereas a Well designed fixed fire suppression system Would cover the entire area. A fixed system may have saved the boat.

Every disaster is a learning opportunity. I am not criticizing the owners. They outfitted their boat like 95% of the boats out there. They acted in a calm seaman like manner.
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Old 29-05-2020, 04:29   #39
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Re: The loss of Kokopelli

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Every disaster is a learning opportunity.
Yes, I think it is entirely appropriate that we respectfully speculate on the situation. Rather learn from other people's disasters than our own!
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Old 29-05-2020, 04:43   #40
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Re: The loss of Kokopelli

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Originally Posted by Snore View Post

Second, this is good lesson for ALL owners. While fire ports are nice, they only give you a few moments of fire fighting (as long as extinguishers) and can only spray a small section of the engine area. Whereas a Well designed fixed fire suppression system Would cover the entire area. A fixed system may have saved the boat.
My thoughts are that if you had the ability to completely shut off to air flow to the engine compartment quickly enough, then a fire could be contained even if the bulkheads were not classified as "Fire Proof" to the standards of the coast guard. Although clearly that would be even more effective if combined with CO2 for fire suppression - powder would not be needed if what we are trying to control is the oxygen in the fuel triangle.

Edit - I also want to say at this point that I had a roughly one gallon size powder extinguisher on my previous boat, and I used it after I thought there was an engine fire (turned out to be a corroded exhaust elbow on my Yanmar). Anyway, the point of me saying this is that I do not think there was enough inside it to have successfully smothered a fire if there had been one.
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Old 29-05-2020, 06:16   #41
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Re: The loss of Kokopelli

I can't remember if we sailed with them in the Salty Dawg rally, met them through SSCA, or just around the Caribbean somewhere, but I remember them and the boat. How sad. I'm glad they're all right. Boats can be replaced.

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Old 29-05-2020, 06:50   #42
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Re: The loss of Kokopelli

A64pilot, you speak with wisdom. Fiberglass burns like greased paper. An electrical short is enough to get it going, because fiberglass does not conduct heat away from the source. You locally pass the flash point of fiberglass very quickly. You do not need a hydrocardon accelerant like gasoline - fiberglass will do the job.

CO2 piped to the engine compartment is my defence of choice. It's cheap, easy to pipe with some copper tubing, and can flood the space without your opening the compartment and letting air in.
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Old 29-05-2020, 07:04   #43
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Re: The loss of Kokopelli

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Originally Posted by Captn_Black View Post
SV Delos has one I think. I am not disputing that it is rare on recreational boats, I just think it is a bad idea to not have one.
SV Delos has a generator in the engine compartment. I have never seen them use a portable generator.

Later,
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Old 29-05-2020, 07:06   #44
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Re: The loss of Kokopelli

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Originally Posted by dannc View Post
SV Delos has a generator in the engine compartment. I have never seen them use a portable generator.

Later,
Dan
Ah ok, I thought i remembered that it had it's own compartment within. Was awhile ago.
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Old 29-05-2020, 07:07   #45
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Re: The loss of Kokopelli

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Originally Posted by tkeithlu View Post
A64pilot, you speak with wisdom. Fiberglass burns like greased paper. An electrical short is enough to get it going, because fiberglass does not conduct heat away from the source. You locally pass the flash point of fiberglass very quickly. You do not need a hydrocardon accelerant like gasoline - fiberglass will do the job.

CO2 piped to the engine compartment is my defence of choice. It's cheap, easy to pipe with some copper tubing, and can flood the space without your opening the compartment and letting air in.
Yea, I think I would not have the same opinion that I stated previously regarding bulkheads if I weren't steel.
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