Fuel hose - requirement for insurance

[Ex-Calif]

So I have a 20 liter tank (~5 gallons) of diesel. The supply to the engine is only 1/4 or max 3/8'.

The vent is probably 1/4" inch has no stand alone thru hull and actually is integrated into the fill neck fitting.

Can an insurance surveyor impose "modern" standards on a 30 year old boat and require factory design to be modified?

[delmarrey]

Originally Posted by Ex-Calif

So I have a 20 liter tank (~5 gallons) of diesel. The supply to the engine is only 1/4 or max 3/8'.

The vent is probably 1/4" inch has no stand alone thru hull and actually is integrated into the fill neck fitting.

Can an insurance surveyor impose "modern" standards on a 30 year old boat and require factory design to be modified?

Mine did! The last survey was for Boats US and I had a 1/2" from 1979, even the fitting was 1/2". So I had to upgrade to modern to satisfy the insurance. Along with a battery compartment vent & fan.

[HopCar]

"Hopcar, you beat me tuit right at the moment I was pushing submit. "
Great minds think alike.

[Terra Nova]

Originally Posted by Ex-Calif

So I have a 20 liter tank (~5 gallons) of diesel. The supply to the engine is only 1/4 or max 3/8'.

The vent is probably 1/4" inch has no stand alone thru hull and actually is integrated into the fill neck fitting.

Can an insurance surveyor impose "modern" standards on a 30 year old boat and require factory design to be modified?

" Can an insurance surveyor impose "modern" standards on a 30 year old boat...".

Someone should.

This needs to be vented overboard.

[hpeer]

Ex-Calif, What my surveyor said was the minimum was either 5/16 or 7/16, but I think I heard 5/16. My Wife agrees, she heard him also. He CLEARLY did not intend 5/8 as he talked about how to connect to my existing tank fittings which would not accept 5/8.

I can find lots of references to 5/8 fittings, which are common. I think that is because if you have a long fill air can't come back out the fill hose and needs to go somewhere. I suspect that they just go with 5/8 for that reason. In my case the fills are like 2" diameter and 2" high so no issue with restricting the air flow. I've not been able to find a reference that tells me what the minimum required size is.

[delmarrey]

Here's the best I can do for you! This comes out of the USCG Boatbuilders Handbook. This is CFR 33 183.520

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[HopCar]

I don't think there is a mandated minimum size on a vent hose. It just has to be big enough to work. If it's too small it can restrict how fast fuel can be pulled from the tank. I think the marine industry has settled on 5/8 because it will work on engines up to a pretty good size.

If I'm wrong about it not being mandated, someone here will tell me.

I recently quoted a fellow on fuel hose for a WWII PT Boat he's restoring. I think he was using 1" vent hose.

Tank vents are going to get complicated on new boats as the EPA wants to restrict fuel vapors escaping into the air. Both Perko and Attwood are coming out with systems that will meet the new regs. I don't think we'll be forced to retro fit existing boats.

[Terra Nova]

Del--that document specifies that the inside diameter of the fittings must be not less than 7/16". Sure sounds like the ID of a 5/8" hose barb fitting.

[delmarrey]

You could be right. Like we say in the hydraulic world. "No flow is better then the smallest fitting"
Here's the one I used, it could have a .093" wall thickness. But I didn't measure it before the install. I had to find one with a long thread. My hull is 1" thick at the deck joint.

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[Ex-Calif]

Originally Posted by Terra Nova

" Can an insurance surveyor impose "modern" standards on a 30 year old boat...".

Someone should.

This needs to be vented overboard.

Not sure what you mean - it does go overboard. The venting in integral to the fill fitting.

5/8 venting is just stupid for my boat.

[hpeer]

Finally got a written copy of the survey.

Vent hose to be 7/16 ID.

[Terra Nova]

Vent hose to be 5/8" ID. (period)

[delmarrey]

Originally Posted by hpeer

Finally got a written copy of the survey.

Vent hose to be 7/16 ID.

Good luck trying to find a 7/16 hose, and a vent fitting to match.

[hpeer]

Yup, he corrected himself to 1/2" I'd.

[Nicholson58]

Originally Posted by HopCar

"I ran undersized VENT hose for my fuel tanks. Bad on me. He said I needed to make it better, but I can't recall the minimum size required. He said 5/16 or 7/16, both sound odd."

5/8" is the most commonly used vent hose. Most of the thru-hull vent fittings are designed for 5/8" hose.

The vent shown (for gasoline) with a flame arrestor, is often mistakenly used for holding tanks & other stuff. I can't comment on the technical atributes of the actual unit shown. They are frequently made of chrome plated pot metal and may be prone to serious corrosion. The screen is dis-similar to the fitting and enhances the corrosion and insects tend to nest over it. While something like this is necessary for volatile fuel, it should never be used for diesel or holding tanks. I don't know where to find a quality version of this device. Fortunately, I had no need for one on the present boat and was able to discard them outright. All of them were corroded shut to about 5% of their design capacity.