Fuel tank vent line

[zoidberg]

My diesel tank has a flexible vent tube of ~8mm ID which is run about 1 metre up to a high point inside the lazarete. There WAS a small s'steel standup pipe with mesh, which protruded into open air. Is such a meshed pipe necessary, or would it suffice to have the tube-end secured up inside the lazarete?

 

[rogerthebodger]

I have vents like this as high as possible on my cockpit bulkhead with a mesh mainlt to keep any water spray from getting in the fuel tanks

 

[vyv_cox]

I think the intention of the mesh is that it will not allow a flame to pass down the tube

 

[sarabande]

Agreed, a meshy bit also prevents determined woodlice as the top of the breather can go sticky with algal growth which is a food source.

 

[Refueler]

I think the intention of the mesh is that it will not allow a flame to pass down the tube

Think a flame screen is a bit OTT on a yacht ? With diesel ?

 

[Refueler]

My tank vents to an open fitting in cabin superstructure side .... 3/4" hose and fitting. No mesh, no flap .. never had water in even when washing windows under sail ...

 

[vyv_cox]

Think a flame screen is a bit OTT on a yacht ? With diesel ?

Probably, but the same devices are used for gasoline in many applications. I have one on my kit car .

 

[Bilgediver]

My diesel tank has a flexible vent tube of ~8mm ID which is run about 1 metre up to a high point inside the lazarete. There WAS a small s'steel standup pipe with mesh, which protruded into open air. Is such a meshed pipe necessary, or would it suffice to have the tube-end secured up inside the lazarete?

Everything has a purpose. The mesh acts as a flame trap. Also keeps errant insects out.

 

[Refueler]

Probably, but the same devices are used for gasoline in many applications. I have one on my kit car .

Spent years on ships with flame screens ....

Gasoline - yes of course.

 

[fisherman]

Friend had a bluebottle in his fuel pickup pipe in the tank. When he opened up the throttle it would go up to the bend at the top and the engine would slow. Took a long time to find it.

 

[Stemar]

One detail, if you do use that fitting, put it in with the tube turned upwards and feed the breather up above it and back down. That'll keep water out.

 

[fisherman]

I had a large transverse tank in a FV, 1000lts. The breather was one side, up through the deck and swan neck. It slopped fuel when full of course, and spilled fuel if the boat bilged over. Stupid design, what you do is have a vent each side which crosses to the other before going up.

 

[Paul1962]

Another consideration may be to ensure your vent line is big enough to allow the tank to "breathe" when filling - probably more pertinent to a motorboat carrying out bigger and more frequent filling.

If memory serves - the breather/vent line on a fuel tank should be in the order of 1.5 tiimes larger than the fill line.

 

[V1701]

I had a large transverse tank in a FV, 1000lts. The breather was one side, up through the deck and swan neck. It slopped fuel when full of course, and spilled fuel if the boat bilged over. Stupid design, what you do is have a vent each side which crosses to the other before going up.

AKA the cockpit drain hose principle...

 

[fisherman]

AKA the cockpit drain hose principle...

Yes of course....but when heeled do you not gradually fill the cockpit, up to the level of the high outlet?