Underdeck tanks

CJL · 14 July 2003, 10:07

Morning all.

I`m pondering about using the underdeck tanks on my boat.
They are 17gals each but they have not been used for some time now (October 2001). The boat has a delta seating layout and the fillers go through the back seat pods down under the deck. Is there anyway of checking for water/corrosion in them and is there a kind of proceedure for refilling them without wasting a fortune on potentially contaminated fuel?
Any help will be greatfully appreciated.
CJL

Alan · 14 July 2003, 10:20

Off topic but you werent out on the Thames around St Kats at 3ish on Saturday were you?

CJL · 14 July 2003, 10:29

Yup.

You lot were giving the cops a big time headache that day!
We were looking for you and went from Putney to the Barrier and only saw at St Kats. Slow start in the morning?

Any advice on the tanks?

CJL

Alan · 14 July 2003, 10:41

Quote:

Originally posted by CJL
Yup.

You lot were giving the cops a big time headache that day!
We were looking for you and went from Putney to the Barrier and only saw at St Kats. Slow start in the morning?

Any advice on the tanks?

CJL

Not sure why you imagine we were giving the cops a headache. We locked out West India at 10.30ish & had got barely 150m before the dirty great Delta police rib stopped us. It was all very friendly a good natured and in the vein of "just wanted to check who you are an what you are doing". Met Police and PLA were contacted as courtesy before the cruise.

We headed as far as Wandsworth bridge by about 11:30 before turning back to lock into St Kats around 12:15. Not sure we'd bother with that again as it takes an age to lock in and out. Departed St Kats around 3ish (when we saw you) & got to Chatham about 5.30.

Ref. the tanks. Do you have anything to suggest that they are not in good condition? (e.g. was the previous owner not using them?). Are there inspection plates you can get at for a look see?
I dont have any bright ideas for anything to fill them up with to see whether they leak. Would be nervous about any kind of pressure test! Mebbe fill one at a time with petrol and only risk the 17 gallons?!

Alan

CJL · 14 July 2003, 11:22

We were listening on the radio to them try to whistle up a boat to check on you. The cops sounded like they were stretched a bit thin in the resources department. The Harbourmaster guys are really good and as long as you dont take the piss on the no speed limit they will happily have a chat and a brew with you. (However they are not impressed when you tow a commercial fridge to them cause you found it and missed it by inches!)

CJL

stuart hedges · 14 July 2003, 14:29

A pressure test should be ok to do, you don't pressure them up much, you can do it with a foot pump, just seal up breathers etc and pressure it up and see if it keeps the pressure there.

With ref to what may be in them the best bet is to just try and empty them as much as possible, and put on new filters and keep checking them. What are the tanks made of, do they not have access hatches

CJL · 14 July 2003, 14:40

Quote:

Originally posted by H2O Events
A pressure test should be ok to do, you don't pressure them up much, you can do it with a foot pump, just seal up breathers etc and pressure it up and see if it keeps the pressure there.

With ref to what may be in them the best bet is to just try and empty them as much as possible, and put on new filters and keep checking them. What are the tanks made of, do they not have access hatches

H20,
I think they are S/S but they dont have any filters visable on them. I`ll give them a try with the foot pump but the breathers go up the filler tubes so I`ll have to get past them and then set up the pump. There are no access hatches but hopefully they will be some after summer! Does anyone else have a Delta and know what their tanks are made of?
CJL

Garygee · 14 July 2003, 19:31

Hi folks

to presure test a tank do the following

seal off all vents, exuts etc just keaving one small(ish) port open.
Make sure they are sealed of well.

Fit to the open port a length of clear pipe and secure well.

Make a U tube out of the clear pipe at least 2-3 feet deep.

Fill the U tube half full with water, or oil ,no more then half full though.

Blow or pump down the open u tube end until bubbles start coming up the tank side, make sure you dont blow any water/oil goes into the tank.

Keep blowing until when you stop the water is 3/4 up the open end and 1/4 up the tank end of the U tube.

Make a careful note of the temprature and try to maintain as much as possible.

Leave for a day or so, if at the same temprature the water is going up the tank side, you have a leak somewhere. If it stays at the same level your OK. The temprature is important though and must be the same when you teke reading as when you started.

Never put too much presure into a tank though it is easy to bow or pop seals by using foot pump or other high presure device.

This methotd is used on big oil and petrol tanks and their is no risk of tank damage.

Regards Gary