Bilge pumps and fuel tanks

[lordy]

We have divided the back of the boat into compartments. In the middle compartment we are fitting a 70l metal tank. Unfortunately its right over where we want to put our bilge pump. The bildge pump will be in a sump mounted into the floor, to catch water from waves and rain etc. Its not draining the under floor area which is going to be completely sealed from the floor areas for floatation reasons (and the fact we want it kept dry. If there is a spill of petrol it will end up in the bilge area, fumes + electrical spark etc. I'm sure lots of you will have faced the same situation. The questions are "do fuel/fuel tanks and bilge pumps mix" and "should we seal the fuel tank area off from the bilge". Any ideas or just what your boat has set up.

The missing floor piece will have the bilge built into it, and the floor piece will be glassed to the exisiting floor. The tank will sit on top of it.

[lordy]

another picy.

1. water runs into bilge. all good.

2. Whoops, accidental fuel spill.

3. Pump starts up, maybe a spark may be not.


Any one got a bilge pump that fuel can get into?

[bungie]

Lordy,

There is a job waiting for you at the Disney animation studio's

[NQCairns]

Heath, I thought most petrol boats from the factory have a bilge and the underfloor tanks drain into it?? How does a person drain unwanted water through or from the tank compartment? Lots of boats have loose access hatches to underfloor tanks, do you have any idea how it is done today? Bloody gravity.

Lordy this is as big a problem to me as it is you , my boat will be ready for pumps in a few months hopefully. I will check what the USCG regulations say on this matter.

I am sure the couple of boats I have had in the past with underfloor tanks would have drained to the bilge but the last one was 10 years ago and I forget the specifics. My guess is that a lot of faith is put into the fuel tank itself as the first and last line of defense, sounds a bit rough though. Gotta get it right first time
Check out here: http://www.uscgboating.org/regulatio...lder/index.htm

Great question Lordy.nq

[blaze]

my mate just had his surveyed for 3 x 30 tassie and the ffuel tank had to be in a sealed, seperate/insulated from all other areas and an external breather to the sealed compartment.
hope this helps
cheers
blaze

[lordy]

Heath, I thought most petrol boats from the factory have a bilge and the underfloor tanks drain into it?? How does a person drain unwanted water through or from the tank compartment? Lots of boats have loose access hatches to underfloor tanks, do you have any idea how it is done today? Bloody gravity.

Lordy this is as big a problem to me as it is you , my boat will be ready for pumps in a few months hopefully. I will check what the USCG regulations say on this matter.

I am sure the couple of boats I have had in the past with underfloor tanks would have drained to the bilge but the last one was 10 years ago and I forget the specifics. My guess is that a lot of faith is put into the fuel tank itself as the first and last line of defense, sounds a bit rough though. Gotta get it right first time
Check out here: http://www.uscgboating.org/regulatio...lder/index.htm

Great question Lordy.nq

Got me thinking because in a week or two we'll be building the area for holding the floor runoff. The obvious place was to drain it into the space between the floor and hull.

Draining throught the floor solved 2 problems:

1. no plumping to get water from the front to back, just a few holes.

2. keeps fuel seperated from water runoff.

But it creates 2 new problems:

1. the timber under the floor doesn't seem to be glassed (may be resined, hard to tell) so that means if it get wet, it has to dry through a bung hole. Drying through a bung hole is going to take a LONG time. Thats prone to rot, so its better to keep it dry in the 1st place.

2. A sealed lower floor to hull should act as safety barrier if the boat get holed from below, or swamped from above. Hopefully enough to keep it afloat. If there are drain holes into the inner hull then its looses some safety value.


A submersible bilge should be safe, its fully sealed so no sparks get out. Unless what happens to Heaths occurs. I'd like to know Heath's brand of pump.

[NQCairns]

Hi Lordie I will not be much help and look forward to what people think and do here normally. My only suggestion and I dont think it would be very practical or trustworthy is to place the pump with the batterys so the divider stops all fumes/petrol. I am sure there are pumps out there that can handle some head (for a price ), run a large-ish dia hose to the low spot in the bilge, the impeller/diaphram should not be a spark hazard. nq

[lordy]

Thats what I'm thinking too. I'd like to put the bilge storage area somewhere else but nowhere else fits. The old other option I can think of is not to have a bilge pumps for the top deck. The decks are too low to self drain, so it could be a bit risky if it cops a wave over the front.

[Heath]

Do not! Have your bilge pump where fuel can enter & come into contact with it.

Situation : on my boat about 3 months back with them shit house Johnson pumps.

Pump going & is noisey, touch it with my hand & get a belt off it.

Reason : water had entered the internals of the pump comming into contact with power.

If fuel as mixed in, I would have been similar to scenario 3 in your post

Seal your fuel compartment from the bilge [smiley=2thumbsup.gif]

[lordy]

Do not! Have your bilge pump where fuel can enter & come into contact with it.

Situation : on my boat about 3 months back with them shit house Johnson pumps.

Pump going & is noisey, touch it with my hand & get a belt off it.

Reason : water had entered the internals of the pump comming into contact with power.

If fuel as mixed in, I would have been similar to scenario 3 in your post

Seal your fuel compartment from the bilge [smiley=2thumbsup.gif]

Thanks, I reckoned a few people must have had some experience with this. I'm pretty sure we will run a hoses from the tank/breather to external filling points/breathers which should stop most of the problems before they start. The tank is metal and solid. I'd like to say "There shouldn't be any leak/fumes with that setup", but they tend to be famous last words.

[NQCairns]

Hi Lordy I spent a couple hours last night searching the web for info, I have mine pegged now .
With yours you could replace and fully seal the pannel in the rear/tank area. Then open up the same lowest hull area just forward of that big partition/bulkhead and place your bilge pumps there, access could be via removable hatch/floor, would fix all your problems regarding sparks/fuel etc and give you a next best bilge area.

With regard to boat rot it needs very specific conditions to survive and condensation is where it thrives, fully wet wood does not promote growth and neither does solid cycles of soden and dry, it is the intermediate phase that causes headaches, if you can forever jump that phase it will never rot out at least in a life time.nq

Two sugestions if you cannot seal your ply/wood. Every week flood the bare area with a strong brine solution for a few hours then drain, or every few months flood the area with anti freeze (ethylene-glycol(sp) is a weak biocide that will impregnate wood) without the anit rust additives etc for a few hours then drain and dry. Both of these substances and procedures will stop most rot in it's tracks and make life for the little buggers just too hard. Use just a little stronger mix than you would in a car radiator and be mindfull of the health implications when handling/useing the stuff. cheers nq

[lordy]

I'll take those ideas on board re rot though I'm still not 100% comfortably will filling it with antifreeze solution. At a guess there could be up to 300-400 litres of air space (thats a lot of solution). Or did you mean let the solution "gas" them? There might be a special antirot solution I can look for.

The hull is a haines, I might give them a call and see what they think.

The floor seems solid as a rock from above. Here is what the floor looks like from underneath (couldn't get a look so we shoved the camera up there for some photos). White spots are ground up fibreglass dust. It was given a wash in the back and some of the water splashes formed the dust into little circles. Just some old bolts holes, and a couple of small black spots which look worse in the compressed photo than the original. I suspose the black spots could be rot, the width between the stringers is around 20cm so its not likely they will cause problems even if the do rot as its not spanning a large area. Boat has been out of the water for about 3 years, it should be nice and dry inside.

[NQCairns]

Hi Lordy, Your floor looks fine, those black spots are probably just knots in the ply. Haines sure did a quality job on your floor if it is original, there is more glass and resin in one foot of your floor than there was on the entire underfloor area of mine and 80% of it lasted 27 years.

Re the antifreeze i thought you were talking about the last portion of the hull between the stringers and below where your tank will sit so a couple of liters of antifreeze in 20 or so of water with the hull tilted up on the trailer would have done it. I also thought (another bad guess) that it was a Hartley glass over ply type of boat.

If the rest of the boat is built like your pic you are in good shape, you could always consider adding those round watertight access hatches through floor anywhere you think there may be a factory designed airtight compartment (they never stayed airtight let alone watertight, they became just big water holding condensation sinks) or even toward the bow along the centreline of the floor/boat keel. These when removed would allow for air to circulate when undercover, no damp = no rot, well.....less rot many years late.

With my boat I am trying to overcome all the problems built into most boats new and most are underfloor yours looks like a better than average one straight up [smiley=2thumbsup.gif]nq

[lordy]

Actually we will be using those round inspection ports. And in some strange places. We are building water proof boxes out of spare bits of fibreglass and mounting on the backsides of walls. We are then using the inspection ports as hatch doors. Should provide a nice 100% watertight place for our phones, cameras, wallets keys etc. Much cheaper than buying those fancy hinged doors at $50-100 a pop.

[Thud]

G'day Lordy,
Just wondering if you had given any consideration to a manual, diaphragm type bilge pump instead of electric. That would overcome any issues you may have with sparking and the manual ones continue to work even if your battery fails.

Cheers,
Tim..