Jefferson 42 Black Iron Fuel Tanks

[Capnal]

My sense, and my experience, is that there are an awful lot of black iron tanks out there that have not a) been leaked on, and b) accumulated water in them .
And if you asked me how I know...1978 Mainshop, 1984 Marine Trader Double
Cabin, forgot the year, but older Albin 27, forgot the year again 44 Gulfstar Motor Cruiser, 2000 31 Camano , 1998 32 Island Gypsy. The Island Gypsy has a fuel polishing system that has been run back and forth, tank to tank, 2 micron filter, and zero water found...19 year old teak decks.
My point is that there is a lot of unwarranted paranoia out there re black iron tanks. Yes, there have been documented problems, but this guy would not replace a black iron tank unless/until there was clear evidence of leakage or other symptoms indicating clear and present exposure to same.

Trying to negotiate a price reduction on black iron tanks with no evidence of leakage would damn sure not fly with this guy.

PS Yes, I'm working on my boat habit...

 

[Derik]

My 1985 Marine Trader tanks are covered in fiberglass matte. I suspect to prevent them from rusting from the outside? I wonder if this was something they did at the Gold Island boat yard which is where it was outfitted after coming from Taiwan.

 

[BruceK]

The "black iron" moniker seems pejorative, to imply inferiority. Not just iron, but black as well! Are they really black metal,or cast iron, if so I take it all back. I`m guessing mild steel.
Because stainless steel with high nickel content (depending on grade) is less likely to rust than plain steel, and fiberglass tanks won`t rust at all, a boat with either of those is preferable in that respect. Preferability can translate into $, so imo ordinary steel tanks detract from value, and potentially price,compared to a similar boat with stainless or other non rusting tank material.
That said, I`ve steel tanks 38 years old, tops have had some work but last time onboard, no leaks. I don`t think it is a huge negotiation area if the tanks appear to be in good condition, but imo they are less valuable than tanks of superior material.

 

[FF]

"compared to a similar boat with stainless or other non rusting tank material."

Stainless fails at the welds in the corners..

Only plastic tanks are "forever" but due to their simple construction multiple tanks are required.
Which can be great or bad, depending.

 

[Steve DAntonio]

They are mild steel, no modern yacht fuel tanks I know of or encounter are iron. Regardless, both rust readily, from inside and out. In many cases failures occur from deck leaks.

A number of other contributors have said, don't be too quick to preemptively condemn a steel tank without good reason, and I share that sentiment. I recently encountered a set of 35 year old steel tanks that were in pretty good shape, certainly serviceable. Inspecting the inside can be the challenge, if the tank doesn't have an access port into each chamber, it should, and these can be added fairly easily with kits.

This article goes into some of the installation-related details, which may be useful for current and replacement tanks. https://stevedmarineconsulting.com/fuel-tank-installation/

Given the choice I always select FRP tanks, however, it's not always practical, and for new and replacement tanks, aluminum is still the most commonly used material.

This article covers fuel tank design and material selection https://stevedmarineconsulting.com/wp-content/uploads/2014/03/FuelTankDesign.pdf

(In Malaysia at the Grand Banks/Palm Beach Yard)

 

[Steve DAntonio]

My 1985 Marine Trader tanks are covered in fiberglass matte. I suspect to prevent them from rusting from the outside? I wonder if this was something they did at the Gold Island boat yard which is where it was outfitted after coming from Taiwan.

This was fairly common on steel tanks, on vessels built in Taiwan in the 80s and 90s. It seemed like a good idea, however, it is flawed I'm afraid. Because the coating is not contiguous, it is "broken" around the fittings, inspection ports etc, water can migrate between tank and FRP, where it wreaks havoc. There is a photo of this in the second article I shared in my previous post. Epoxy coating remains the best approach for steel tanks.

(In Malaysia, at the Grand Banks/Palm Beach Yard)

 

[Dan_can]

They are mild steel, no modern yacht fuel tanks I know of or encounter are iron. Regardless, both rust readily, from inside and out. In many cases failures occur from deck leaks.



A number of other contributors have said, don't be too quick to preemptively condemn a steel tank without good reason, and I share that sentiment. I recently encountered a set of 35 year old steel tanks that were in pretty good shape, certainly serviceable. Inspecting the inside can be the challenge, if the tank doesn't have an access port into each chamber, it should, and these can be added fairly easily with kits.



This article goes into some of the installation-related details, which may be useful for current and replacement tanks. https://stevedmarineconsulting.com/fuel-tank-installation/



Given the choice I always select FRP tanks, however, it's not always practical, and for new and replacement tanks, aluminum is still the most commonly used material.



This article covers fuel tank design and material selection https://stevedmarineconsulting.com/wp-content/uploads/2014/03/FuelTankDesign.pdf



(In Malaysia at the Grand Banks/Palm Beach Yard)

Thank you Steve, very interesting article. What about ceramic based coatings (such as Mascoat and others) to prevent rust? I’m just ignorant on the matter so excuse me if it is silly question.

 

[kchace]

Thank you Steve, very interesting article. What about ceramic based coatings (such as Mascoat and others) to prevent rust? I’m just ignorant on the matter so excuse me if it is silly question.

There are various "modern" high tech coatings which could be very beneficial. But considering the cost and the fact that most steel tanks last at least 30 if not 40 or 50 years, what's the incentive? Besides, IMO if a yard was considering the extra cost of high tech coatings, why not just build the tank out of fiberglass and be done with it?

Ken

 

[Steve DAntonio]

Thank you Steve, very interesting article. What about ceramic based coatings (such as Mascoat and others) to prevent rust? I’m just ignorant on the matter so excuse me if it is silly question.

Much like powder coat, I have had little luck with, or respect for, ceramic coatings, as sexy as they sound, and claim to be, they lack the flexibility and adhesion of a two part epoxy. And, they have the same issue as FRP over metal, water enters at the breaches. Don't fall for the ceramic, or powder coat, lines;-) When it comes to rust prevention of metal, epoxy is the last word.

(In Singapore, homeward bound)

 

[C lectric]

Even better than coatings. Keep the tanks dry, BONE dry. Do not allow deck leaks to wet them. Keep your fill fittings sealed to the deck and the O rings in good condition and greased lightly. Replace the O rings every few years. Keep bilge water under control so it cannot slosh enough to get on the tanks or where the tanks sit.

If you find wetness on or around the tanks find and stop the source. Yes, iron will rust if humidity is high but the rate of corrosion is very low unless water accumulates in an area in contact with the steel.

The biggest cause that I am aware of causing steel tanks to rust from either inside or outside is water allowed to collect and keep the steel wet.

Keep them dry, inside and out.
JMO