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Dave_S · 25-05-2019, 23:24

Unleaded not desiel.

I'm thinking of putting in two fuel bladders to replace the plastic outboard tanks and Jerry can refills.

Anyone have issues with bladders ? Maybe grit or a loose screw wearing a hole ?

They will go into separate compartments under the floor on the rear deck. 2x200lt.

**Pete7** · 25-05-2019, 23:34

Well, petrol fumes are heavier than air, so are these compartments totally sealed from the rest of the boat and also vented?

That's a huge amount of petrol to carry.

Pete

RaymondR · 25-05-2019, 23:37

I would not use bladders for petrol on a boat. They are to vulnerable to damage and petrol fumes to volatile.

**Pete7** · 25-05-2019, 23:49

I am guessing he has a pair of outboards on a cat, so limited options. Still a lot of weight on the stern, that's the same as 4 large blokes.

Dave, presumably you are looking at something like the Turtlepac range.

Pete

kas_1611 · 25-05-2019, 23:50

Only thing I would say is long term storage of fuel, such as unleaded, can result in nasty gunk and blocked carbs or injectors.

Are you really going to use 400 litres of unleaded fuel in a reasonably short duration? I had 5l go off in a few months stored in a sealed metal jerry can, with Fuel Treatment added.

Plus you are adding about 300kg to the stern of your boat so think about the weight implications too.

Dave_S · 26-05-2019, 01:14

Quote:

Originally Posted by RaymondR

I would not use bladders for petrol on a boat. They are to vulnerable to damage and petrol fumes to volatile.

They do some fairly impressive testing but this is my worry, half my fuel in one container.

Quote:

Originally Posted by Pete7

I am guessing he has a pair of outboards on a cat, so limited options. Still a lot of weight on the stern, that's the same as 4 large blokes.

Dave, presumably you are looking at something like the Turtlepac range.

Pete

Yep, on the outboards.

I saw the Turtlepac at the show, seems pretty tough.

As you say a lot of weight up the back, I have a total of 100lt in the same place now and Jerry cans up front. It is a PITA when its a bit rough bringing back the jerrys and cyphen them. I think your right though about the weight, so maybe I should get smaller ones or not fill them.

Quote:

Originally Posted by kas_1611

Only thing I would say is long term storage of fuel, such as unleaded, can result in nasty gunk and blocked carbs or injectors.

Are you really going to use 400 litres of unleaded fuel in a reasonably short duration? I had 5l go off in a few months stored in a sealed metal jerry can, with Fuel Treatment added.

Plus you are adding about 300kg to the stern of your boat so think about the weight implications too.

I don't use much fuel now in and out through the leads and on the anchor/mooring. I'm thinking of cruising 6 months of the year from next year to some remote places and up rivers etc.. and I would like the capability.

At the moment I have fuel go off in the outboard tanks, I like the bladders because there is no venting and you can empty the air out so hopefully with a small amount of treatment it should last quite a while ???

Dave_S · 26-05-2019, 01:17

Quote:

Originally Posted by Pete7

Well, petrol fumes are heavier than air, so are these compartments totally sealed from the rest of the boat and also vented?

That's a huge amount of petrol to carry.

Pete

Yep it's isolated, vented top and bottom externally, completely sealed to the interior.

Bruce K · 26-05-2019, 01:58

I have 2x 300l bladders custom made by Fleximake in Melbourne, no problems with them, BUT I only store diesel in them, I would not use them for petrol, unless in a bottom vented isolated locker.

thinwater · 26-05-2019, 06:14

Quote:

Originally Posted by Dave_S

...
At the moment I have fuel go off in the outboard tanks, I like the bladders because there is no venting and you can empty the air out so hopefully with a small amount of treatment it should last quite a while ???

Add a silica gel vent filter. the gas won't go off for over a year. Also a good additive, like Biobor EB.

Sail Delmarva: Gasoline and Fuel Tank Vent Filters

(I'm a chemical engineer and have done a good bit of testing on the subject of gasoline stability in boats.)

---

I am also a licensed tank inspector, and bladders for gasoline scare me. No thanks.

**a64pilot** · 26-05-2019, 06:24

And then I’d tell your that there are millions of airplanes flying around with bladder tanks, and of course you don’t see many fireballs in the sky.

It all has to do with being completely sealed from the rest of the boat, and I mean of course air tight, think propane locker.
That is I think the challenge.
Why not have custom plastic gas tanks made?
These people will make custom tanks to your drawings.
http://triplemplastics.us/#&panel1-1

AKPilot · 26-05-2019, 07:59

I was very sceptical of fuel bladders too before I bought them. Now after a couple of seasons of throwing a 238 gal and a 300 gal turtle pack bladder in and out of aircraft to haul bulk fuel I would say they are very durable.

I do take a lot of precaution to sweep out the floor and even lay a sheet of cardboard down underneath them but they are surprisingly durable. I am loading and unloading them daily in the summer. I have even been known to throw some lumber or something on top of the bladders to deliver to customers needing the fuel.

Turtlepack does say to inflate them if you are going to store them empty so that is something to think about. But for a fixed position bladder I wouldn’t worry about durability as long as you took reasonable care to make sure they won’t rub on something.

Dave_S · 26-05-2019, 15:09

Quote:

Originally Posted by thinwater

Add a silica gel vent filter. the gas won't go off for over a year. Also a good additive, like Biobor EB.

Sail Delmarva: Gasoline and Fuel Tank Vent Filters

(I'm a chemical engineer and have done a good bit of testing on the subject of gasoline stability in boats.)

---

I am also a licensed tank inspector, and bladders for gasoline scare me. No thanks.

Good to know. It would be good to get rid of the smell too.

Do you have to shut the vent off when not in use or is that with it always open ?

Dave_S · 26-05-2019, 15:12

Quote:

Originally Posted by a64pilot

And then I’d tell your that there are millions of airplanes flying around with bladder tanks, and of course you don’t see many fireballs in the sky.

It all has to do with being completely sealed from the rest of the boat, and I mean of course air tight, think propane locker.
That is I think the challenge.
Why not have custom plastic gas tanks made?
These people will make custom tanks to your drawings.
Triple 'M' Plastics

I'll measure up and get a price, the issue is the opening at the top to put the tank in is smaller than the cavity for it but I might get a reasonable tank in by sliding it in on an angle.

Dave_S · 26-05-2019, 15:18

Quote:

Originally Posted by AKPilot

I was very sceptical of fuel bladders too before I bought them. Now after a couple of seasons of throwing a 238 gal and a 300 gal turtle pack bladder in and out of aircraft to haul bulk fuel I would say they are very durable.

I do take a lot of precaution to sweep out the floor and even lay a sheet of cardboard down underneath them but they are surprisingly durable. I am loading and unloading them daily in the summer. I have even been known to throw some lumber or something on top of the bladders to deliver to customers needing the fuel.

Turtlepack does say to inflate them if you are going to store them empty so that is something to think about. But for a fixed position bladder I wouldn’t worry about durability as long as you took reasonable care to make sure they won’t rub on something.

Thanks

They are under the floor on the back deck and they do get grit inside, I could see a fish hook or some swarf from drilling a hole find it's way in, I might look for alternatives like those suggested above.