Replacing original black iron tank

[phorvati]

I have a 250gal original iron diesel tank that is leaking and I would like to turn it into a usable diesel tank. I've heard that a lot of older Tayanas have this issue.

It would be impossible without major interior tear down to fit new rigid tank of same or even lesser but reasonable capacity. I guess i would have to remove the engine and then I could go the rigid tank route.

I have enough access to cut a large chunk of it out, but at most I would need to put two rigid tanks and even both would be less than the 250Gal that was there by a significant factor.

I am considering ordering a ATL fuel bladder designed to fit within the rigid tank space per this description.

Marine Fuel Bladders and Auxiliary Fuel Tanks

Anyone have any other suggestions?


Thanks
Petar

[Tomodore]

I don't know your specific boat but also what I don't know is what your plans are in the short and medium term. Are you leaving for a circumnavigation in 6 months or is this a weekend and summer vacation vessel? Are you able to spend whatever it takes or can you manage and thrive on a shoestring. I am not implying any right answer here just how important the 250 gallon capacity is for your situation. Perhaps some poster has a magical cheap and easy solution to a complete fix but most likely it will be a PITA and $$ to make it like New. I expect you already know that. If the cheap and less than perfect solution will jive with your short and medium plans I say go now.

[phorvati]

I think i will put the bladder right now, then in 5-10 years, when i pull Ford Lehman NE90 out for a rebuild, i will get aluminum made to size. I already had local tank shop (luther's) make me a 47gal aluminum custom tank which works very well. I now have 47gal and 33gal aluminum (new) and this rusty sack of iron with 250gal volume. We spend summers in RI, then in the fall i take the boat somewhere south, between NC and FL for the winter. I work full time so i take a week off to sail the boat up and down the US east coast. I don't have the luxury of time to wait on weather. Lately, weather in the fall and spring has been either violent or calm. So I have been finding my self in either too much wind or n need to motor 3-4 days. Lehman uses 1.35gal/hour so Ive been having to jump off and re-fuel so far every time.

[Mike OReilly]

I have no experience to offer Petar, but I've been studying the same question for some time now. I too have a boat with old iron diesel tanks. So far the main tank has been fine, but I assume it will die someday.

Based on my research I've been planning to do as you suggest, and insert a quality bladder once this happens. So I'll be interested to read about your experience with this. Some have done this and reported good results, but there are warnings about friction and chafe.

Good luck . Keep us posted.

[Tayana42]

Petra, I’ve posted this before so you may already have this information.

I did this after one of my black iron diesel tanks developed a pin hole leak. Same problem of inaccessibility for removal of the tank without demolishing the interior of the cabin. In addition to opening up the top of the tank you have to remove any baffles in the tank and grind them down smooth so as not to have any chafe on the bladder. I also padded the inside of the iron tank with rubber decking tiles before inserting the bladder. You want a high quality bladder tank builder to manufacture one to the exact dimensions of the inside of your existing tank so you need to measure the rhomboid shaped tank very carefully.


I used Aero Tec Laboratories, Inc.
Spear Road
Ramsey, New Jersey 07440


201-825-1400
ATL@ATLINC.COM


Cost was $1296 in 2004. That was in addition to the cost of grinding out the baffles in the iron tank and installing the bladder.

I can add that to date I’ve had no problems with this tank insert.

[phorvati]

Originally Posted by Tayana42

Petra, I’ve posted this before so you may already have this information.

I did this after one of my black iron diesel tanks developed a pin hole leak. Same problem of inaccessibility for removal of the tank without demolishing the interior of the cabin. In addition to opening up the top of the tank you have to remove any baffles in the tank and grind them down smooth so as not to have any chafe on the bladder. I also padded the inside of the iron tank with rubber decking tiles before inserting the bladder. You want a high quality bladder tank builder to manufacture one to the exact dimensions of the inside of your existing tank so you need to measure the rhomboid shaped tank very carefully.


I used Aero Tec Laboratories, Inc.
Spear Road
Ramsey, New Jersey 07440


201-825-1400
ATL@ATLINC.COM


Cost was $1296 in 2004. That was in addition to the cost of grinding out the baffles in the iron tank and installing the bladder.

I can add that to date I’ve had no problems with this tank insert.

How do you know when its full? Is there a vent? and what do you use for sensing level? I have tank tender which uses a suction tube and measures inches of Hg.

[Tayana42]

Yes there is a vent. I use a dipstick ( wood dowel ). Old school but works. I sound the tank before filling and approximate the amount of fuel to take on. Then as it is getting close to full I use the dipstick to check the fuel level. I keep track of engine hours and know the fuel consumption rate so it’s easy to estimate how much fuel I’ve used and then confirm with the dipstick as needed.

[Scubaseas]

Originally Posted by phorvati

I have a 250gal original iron diesel tank that is leaking and I would like to turn it into a usable diesel tank. I've heard that a lot of older Tayanas have this issue.

It would be impossible without major interior tear down to fit new rigid tank of same or even lesser but reasonable capacity. I guess i would have to remove the engine and then I could go the rigid tank route.

I have enough access to cut a large chunk of it out, but at most I would need to put two rigid tanks and even both would be less than the 250Gal that was there by a significant factor.

I am considering ordering a ATL fuel bladder designed to fit within the rigid tank space per this description.

Marine Fuel Bladders and Auxiliary Fuel Tanks

Anyone have any other suggestions?


Thanks
Petar

Step #4 is the tricky part. http://atlinc.com/atl-marine-fuel-bl...allation4.html

What Tayana42 said.

If you know where the tank is leaking many have sealed their tanks successfully using epoxy and red seal or similar.

Use a piece of heavy/dense foam or something like rubber sheet inside the tank as it will be difficult to get where the baffles were cut out smooth.

I put in a bladder tank for water over 20 years ago on my old boat. Still working fine to date.

[phorvati]

Good thing I didn't go to town with angle grinder just yet. There is an obvious single hole that can be welded. I'm not sure how the rest of the bottom seam looks. This is my first time looking inside an iron diesel tank. I did see the inside of my old alumnum tank and those holes were about the size of a dime and round. This seems to be primarily a weld failure from rust
Does anyone know if this is repairable or not. Do I give that a shot first prior to dropping 1500 on a bladder. In 5 years or so I plan to pull the engine out anyway and at that time I will have the new aluminum tank made.

[Searles]

My perry 48 had black steel fuel ,diesel tanks ,stripped out cabin sole and some panel work, cut the old tank out with small angle grinder ,not a nice job ,made up glass vinalester panels 6mills plus thick cut to shape coated with fuel tank epoxy ,glass epoxy in plus baffles with flange around top edge ,bored and tapped for 6mill ss bolts on 4 inch cntrs good gasket all done 525liters Will last forever used hull glass for bottom now have double bottoms ,have done same for fw tanks all double bottoms ⛵️⚓️

[rbk]

Originally Posted by phorvati

Good thing I didn't go to town with angle grinder just yet. There is an obvious single hole that can be welded. I'm not sure how the rest of the bottom seam looks. This is my first time looking inside an iron diesel tank. I did see the inside of my old alumnum tank and those holes were about the size of a dime and round. This seems to be primarily a weld failure from rust
Does anyone know if this is repairable or not. Do I give that a shot first prior to dropping 1500 on a bladder. In 5 years or so I plan to pull the engine out anyway and at that time I will have the new aluminum tank made.Attachment 236887Attachment 236888Attachment 236889Attachment 236890Attachment 236891Attachment 236892Attachment 236893

Tayang liked to use the thinnest metal possible, that said I would totally see about getting it welded or even cutting the whole top off and adding an additional layer to the bottom if possible. If removing I would go poly and modular system. You may loose a little capacity but having multiple tanks and a small fuel pump is a huge safety and maintenance factor to consider.

[Scubaseas]

Clean really, really well. Treat with POR15 or similar, grind per manufacturer, apply a sealant like DK2 or use epoxy or vinylester resin and fiberglass reinforcement.

https://www.armorshieldlining.com/pe...nk-lining.html

Rhino 9700, Locktite, JB Weld and others make epoxies approved for immersion in diesel. You could glue in a piece of angle iron if worried about the size of the hole but from what I see it should be an easy fix. Depends on how much metal is left. Or just laminate some fiberglass cloth like 1708 onto a cleaned surface using an approved epoxy or vinylester resin. epoxyworks.com has some good info on tanks made of epoxy.

Could you weld it? Maybe. Depends on how thick the rusted metal is and what's behind it. I doubt you will find anyone willing to weld the tank in situ but I could easily be wrong.

[phorvati]

Originally Posted by Scubaseas

Could you weld it? Maybe. Depends on how thick the rusted metal is and what's behind it. I doubt you will find anyone willing to weld the tank in situ but I could easily be wrong.

Ive been practicing with a stick welder. Last fall i bought one, and so far Ive been working with stainless tubing, I'm getting a hang on how easy it is to blow hole. It would be a bitch to weld inside anything more than that one crack that is about 3/4" by 1/16" in size.
Walls are surprisingly thick. I did not measure with the caliper yet but it felt very heavy. If anything I would say that ta-yang yard overbuilt stuff, judging by the layup of glass, framing used to build the interior and even chain plates. They are thick, but stainless was inferior.

[Scubaseas]

I'd be worried about what is behind the tank and if it will catch fire when welding. If I had to do it I'd use TIG or MIG and have a squirt bottle and bucket of water at hand along with a CO2 extinguisher. But then I haven't used a stick welder in maybe 50 years. If you can get access to that part of the tank on the outside and slide a sheet of something like sheet metal behind it as a heat/flame shield have at it. Use a good mild steel rod. Maybe practice a bead or two on the access cover plate before diving in to weld the hole shut.

[phorvati]

Originally Posted by Scubaseas

I'd be worried about what is behind the tank and if it will catch fire when welding. If I had to do it I'd use TIG or MIG and have a squirt bottle and bucket of water at hand along with a CO2 extinguisher. But then I haven't used a stick welder in maybe 50 years. If you can get access to that part of the tank on the outside and slide a sheet of something like sheet metal behind it as a heat/flame shield have at it. Use a good mild steel rod. Maybe practice a bead or two on the access cover plate before diving in to weld the hole shut.

Now that i think about it, that entire bottom corner on the outside has been probably soaked in diesel. Outside along the bottom there is fiberglass tabbing and tank was rusting from outside as well. So diesel/water was soaking between the rusty tank on the outside and fiberglass tabbing. But I emptied that tank and whatever was left in it in 2017 and its been empty every since. I can still see potentially that igniting as I go to weld it on the inside.