Welding above Diesel tank

[H.C.Astell & Co]

Hi all

I have had our first boat for about 6 months now, but there are a few things that we need to change, and in this topic i would like to ask, if its ok to weld/cut the stern seat rails as they are too high for us both.

I will be "Ark" (sorry i had too) Arc welding and due to the position do i still need to start disconnecting wiring from starter and alternators etc

 

 

Appreciate any help on this matter.

 

Harvey

Edited October 31, 2011 by H.C.Astell & Co

[bottle]

Welcome.

 

Is the boat a cruiser stern?

 

If it is, then, in my opinion, do not lower them.

[Guest User]

ANswered here .... http://www.canalworld.net/forums/index.php?showtopic=23628&pid=391735&st=0entry391735

[H.C.Astell & Co]

Welcome.

 

Is the boat a cruiser stern?

 

If it is, then, in my opinion, do not lower them.

Its a trad, and when sitting we cant touch the floor or rest our feet.

 

 

ANswered here .... http://www.canalworld.net/forums/index.php?showtopic=23628&pid=391735&st=0entry391735

I had read that topid before posting my new one :-) My worry is welding above the diesel tank, with a full tank, but i forgot to put that info in, sorry..

Edited November 1, 2011 by H.C.Astell & Co

[steelaway]

Hi all

I have had our first boat for about 6 months now, but there are a few things that we need to change, and in this topic i would like to ask, if its ok to weld/cut the stern seat rails as they are too high for us both.

I will be "Ark" (sorry i had too) Arc welding and due to the position do i still need to start disconnecting wiring from starter and alternators etc

 

 

Appreciate any help on this matter.

 

Harvey

 

 

 

What about having some foot rests welded on to the existing seat post?

 

It will be up to your welder whether he was willing to weld to the tank. I have seen it done without a problem.

 

Alex

[cereal tiller]

not sure if elfin safety would approve,but welding on diesel tanks is often carried out,one way of reducing fire risk is to duct exhaust gases from a diesel engine into the tank while welding is carried out.

[The Bagdad Boatman (waits)]

It is the gases in the tank that can explode a full tank is safer. If the tank is completely empty water with washing up liquid and an airline to create bubbles works well.

[bizzard]

I can't understand what all the fuss is about as it sounds like he only wants to lower the taffrail seats,and not actually welding anything onto the tank itself. The only thing to be careful of is the whereabouts of the tank breather as ''SOME ARE FITTED ONTO ONE OF THE HOLLOW TAFFRAIL TUBES SOMEWHERE SO BEWARE'',other than that just stick parcel tape over the filler and put bucket over it,that goes for a tank mounted breather too.The weathers cool now so not much in the way of fumes.

Just a spot of inituitive and sense required that all.

Edited November 2, 2011 by bizzard

[larkshall]

H and E would say you SHOULD drain the diesel tank and refill to the brim with water, though nitrogen gas can also be used.

 

But with an arc welder I'd probably do it with brim full diesel tank No airspace just to be safe.

 

Anyway when you say above the tank, I presume you mean not actually touching the tank? Oh I tend to use heat proof matting to cover the surrounding area. Partially to protect paintwork, and to stop welding clag sticking to the weld area.

 

Its always advisable to disconnect batteries and alternators. 99 time out of a hundred its ok, but.....

Edited November 2, 2011 by larkshall

[Guest]

Would not an even safer way to do be to cut off from the top, grind off the remaining 'stumps' from the top plate and re-weld the top plate to the now shorter legs.

 

(Refit the tops if you have them).

 

That way you are not welding to the actual top of the tank.

[bizzard]

Would not an even safer way to do be to cut off from the top, grind off the remaining 'stumps' from the top plate and re-weld the top plate to the now shorter legs.

 

(Refit the tops if you have them).

 

That way you are not welding to the actual top of the tank.

Exactly,thats how i read it in the first place.

Its just the breather fitting in case its on one of the hollow seat uprights which might be open to the tank,as some are.

[Guest]

Exactly,thats how i read it in the first place.

Its just the breather fitting in case its on one of the hollow seat uprights which might be open to the tank,as some are.

 

Ah yes - we hired a boat like that - I had no idea what it was and it bugged me till I asked the yard when we got back, you can (just) see it in the this picture, on the leg for the starboard seat nearest the tiller.

 

[bizzard]

Ah yes - we hired a boat like that - I had no idea what it was and it bugged me till I asked the yard when we got back, you can (just) see it in the this picture, on the leg for the starboard seat nearest the tiller.

 

Thats the kiddy,a very common practice.

[alan_fincher]

H and E would say you SHOULD drain the diesel tank and refill to the brim with water, though nitrogen gas can also be used.

Wasn't taht the naturist magazine we used to snigger over as schoolboys ?

 

If so, is their opinion on welding to diesel tanks that valid ?

[H.C.Astell & Co]

I have no vent welded to the uprights, but that said could the tube be used as a vent with no vent socket welded in situ?

Its a niggly job i would like to do, and can do easily, but i do worry about that tank!!!

I thought diesel had to be compressed to combust, or thrown on a fire to go up? i didnt think (or hope) fumes from diesel caused a worry.

 

The process i had in mind, had 2 options

grind of at base, cut out 4" weld back

or

cut 4" out from top and pop it back together again with a weld

[bizzard]

I have no vent welded to the uprights, but that said could the tube be used as a vent with no vent socket welded in situ?

Its a niggly job i would like to do, and can do easily, but i do worry about that tank!!!

I thought diesel had to be compressed to combust, or thrown on a fire to go up? i didnt think (or hope) fumes from diesel caused a worry.

 

The process i had in mind, had 2 options

grind of at base, cut out 4" weld back

or

cut 4" out from top and pop it back together again with a weld

If your boat has passed BSS examinations in the past it must have a fuel tank vent of correct flame proof design somewhere,ideally behind the tiller where its protected,as you do have an integral tank.

If you've not got one at all your engine would soon stop. ''Vacuuming of the fuel tank''.

One could be fitted in your seat upright tube somewhere,but you would have to drill with an extra long drill bit through the tube into your fuel tank.And keep lots of grease on the drill bit to prevent any sparks and to retain and prevent swarf from falling into the tank.

Edited November 2, 2011 by bizzard

[H.C.Astell & Co]

If your boat has passed BSS examinations in the past it must have a fuel tank vent of correct flame proof design somewhere,ideally behind the tiller where its protected,as you do have an integral tank.

If you've not got one at all your engine would soon stop. ''Vacuuming of the fuel tank''.

One could be fitted in your seat upright tube somewhere,but you would have to drill with an extra long drill bit through the tube into your fuel tank.And keep lots of grease on the drill bit to prevent any sparks and to retain and prevent swarf from falling into the tank.

I dont doubt you, i just cant see one on the framework to seats.

[bizzard]

I dont doubt you, i just cant see one on the framework to seats.

The usual place is directly on the tank top,often behind the tiller,sometimes they're screwed into the top of one of your mooring dollies,a ridiculous place in my opinion.

[H.C.Astell & Co]

The usual place is directly on the tank top,often behind the tiller,sometimes they're screwed into the top of one of your mooring dollies,a ridiculous place in my opinion.

You may of hit the nail on the head, i have one brass fitting on top of one of the dollies

[Guest]

The usual place is directly on the tank top,often behind the tiller,sometimes they're screwed into the top of one of your mooring dollies,a ridiculous place in my opinion.

 

do I have to dig out another picture Biz????

 

 

Ignore the crap fender - long since replaced -

 

tank vent clearly visible still though...

Edited November 2, 2011 by MJG

[bizzard]

You may of hit the nail on the head, i have one brass fitting on top of one of the dollies

That'll be it. Just be careful with mooring ropes and or kicking it hard as they're only brass although quite solid.

[H.C.Astell & Co]

That'll be it. Just be careful with mooring ropes and or kicking it hard as they're only brass although quite solid.

Ahh, see you learn something new every day,cheers..

 

I will be extra carefull now i know what it is..

Edited November 2, 2011 by H.C.Astell & Co

[ditchcrawler]

Just cut through the legs as low as possible and grind the stumps flush with the deck, forget about welding and throw what's left away.

[H.C.Astell & Co]

Just cut through the legs as low as possible and grind the stumps flush with the deck, forget about welding and throw what's left away.

Im not sure i understand, if i cut the stumps low down and grind them flush, i have to re weld them back with the 4" taken out, how can i forget about welding?

[bizzard]

Im not sure i understand, if i cut the stumps low down and grind them flush, i have to re weld them back with the 4" taken out, how can i forget about welding?

I don.t think Ditchcrawler's read the thread properly,he seems to think that you want to do away with seats altogether.

Just shorten em to the height you want and weld the seats back on.