Fuel tank cleaning

Dec 8, 2014
9
Catalina 30 Fairhaven, MA
All,
Looking for some information on cleaning a diesel fuel tank?
I currently have a 17 gallon aluminum fuel tank which is original to the boat. My boat is a 1986 Catalina 30 and I have replaced all other components in the fuel system just due to age and was wondering if the fuel tank can be cleaned?

Thanks,
Tim H.
 
Jan 6, 2010
1,520
About,

There are two ways to clean the tank.

#1. Fuel polishing method.
A portable recirc. pump & filter system is hooked up to your tank. This agitates the fuel in the tank (hopefully) suspending any particles/bugs/sludge. In tanks without baffles like yours, this system works pretty well.

#2. The manual way.
You probably do not have an inspection plate in the top of your tank. I didn't so, I cut an 8inch square & added a cover plate. If you have an access plate, you're lucky. I prefer this method for me as, I am assured of a clean tank along with visible inspections & easy cleaning.

CR
 

Bob S

.
Sep 27, 2007
1,771
Beneteau 393 New Bedford, MA
Tim,

I agree with CR. The tank on our C30's are easily accessible. I cut a 6" opening with a hole saw and fabricated a plate. In the spring I clean it out using cotton rags from Lowes. It gives me peace of mind knowing my fuel is clean. Polishing is preferred when the tank isn't accessible.

How long have you been in Fairhaven? I was thinking of moving that way this season and getting a slip. I've been on a mooring for the last 7 years.
 
Dec 8, 2014
9
Catalina 30 Fairhaven, MA
CR
Thanks for the help. Looks like it will be the manual way by opening up an access hole in the top of the tank for me.
I don't mind doing the work and it gives me a better knowledge of what I have on board.
 
Dec 8, 2014
9
Catalina 30 Fairhaven, MA
Bob,
Also thanks for the reply. I will be going with what you and CR have suggested by way of an access port.

As far as Fairhaven, I have been at the Fairhaven shipyard for 3 seasons and it is great. I have been on a slip there the entire time (except for winter haul out). I like the idea of being behind the New Bedford Hurricane barrier when the weather gets really nasty. There is a large sailing community at the shipyard and I'm considered a new comer. Most people have been there for 15-20 years. Very secure neighborhood an some good restaurants within walking distance for your boat.
And no I don't work for them.
 
Feb 26, 2008
603
Catalina 30 Marathon, FL
Has anyone pulled their tank to inspect it?

I've been debating doing this for a couple of seasons now. It's held in with four screws so it "should" be straightforward to remove, check for corrosion and clean.

It would be a good time to replace all the fuel hoses as well.
 

dj2210

.
Feb 4, 2012
337
Catalina 30 Watts Bar
Replaced my fuel tank last year on my 1990 C30. It had four tangs that where glassed onto the hull. Ground the glass away and removed the tank. Replaced with same from original manufacturer and glassed in blocks to use straps so tank could be removed easily if ever needed (ie replace the hot water heater).
 
Oct 26, 2010
1,883
Hunter 40.5 Beaufort, SC
Cutting the hole?

Tim,

I agree with CR. The tank on our C30's are easily accessible. I cut a 6" opening with a hole saw and fabricated a plate. In the spring I clean it out using cotton rags from Lowes. It gives me peace of mind knowing my fuel is clean. Polishing is preferred when the tank isn't accessible.

How long have you been in Fairhaven? I was thinking of moving that way this season and getting a slip. I've been on a mooring for the last 7 years.
Bob and CR
For those of you have cut a hole for an access plate. How did you keep from getting shavings into the tank when you cut the hole? Thanks
 

RichH

.
Feb 14, 2005
4,773
Tayana 37 cutter; I20/M20 SCOWS Worton Creek, MD
Some thoughts on About Time2's tank cleaning:

1. Dont waste your time and money on 'fuel polishing' a dirty tank, especially if you cant get inside to either 'steam' power wash or hand scrub. So-called fuel polishing only cleans the oil not the tank walls.
2. On a blind tank that you dont have an access port, etc., fairly 'decent' results can obtained by using an enzymatic chemical tank cleaner
http://www.amazon.com/Star-Brite-St...=UTF8&qid=1420640682&sr=8-8&keywords=startron
With such a product you wont get 'all' the crud out but most of the 'deposits' will be dissolved, thus lessening the potential of their 'breaking loose' from the surfaces during heavy sea states. Long term soak is best with an 'enzymatic' and will 'stun' / kill and then 'dissolve' the microorganisms and their 'products'. After treating with the enzyme, Id then recommend to drain the tank and take the residual home and burn it in your home oil burner. Id then repeat the process if there is a LOT of 'discolored' oil when you drain it. Keep repeating until the tank contents begin to remain 'clear'.
Obviously youd need to have spare 'filters' on board just in case some of the 'residual' breaks loose. The typical sailboat sized Racor, etc. only has about 25-40 GRAMS of 'dirt capacity' before plugging - a trivial amount before 'plugging'.

3. for a small tank such as this, consider to remove it and either instal a 'hand hole' and clean it yourself or send it out to be ultrasonically cleaned ... look for a 'radiator service' who caters to big 'trucks'.
Caution - for gasket material for any 'access ports' in fuel tanks should probably be Viton® rubber, due to the increasing 'mixes' / blends with 'bio-fuels'. Increasingly BUNA and Neoprene will soften and easily deform in the presence of the organic acids that are present in so-called 'bio-fuels', especially 'reclaimed' bio-fuels.

4. if you do any cutting while the tank is still in the boat, first empty the oil, fill it with WATER when you do any metal cutting - a safety precaution. Can prevent a loud 'BOOM' while metal cutting.

5. metal cuttings - can be minimized by first boring a 1-2" dia. hole, then placing 'sticky tape' (I like StickyAss duct tape) on the 'underside' BEFORE you fill with water. Once you have a hand hole any remaining cuttings can be easily removed, manually with a soft cloth, etc.

Good luck. Hope this helps.
 
Dec 8, 2014
9
Catalina 30 Fairhaven, MA
RichH.
Thank you for the information. Especially the info on the gasket material. I will be using the material you suggested when making a new cover plate for the access hole. I will be removing the tank and taking it home to perform the cleaning. It is a long winter and I will have plenty of time to do this.
 

jrowan

.
Mar 5, 2011
1,294
O'Day 35 Severn River, Mobjack Bay, Va.
I agree with the concerns of the above post regarding potential for metal shavings to get into your tank from cutting an inspection port with a hole saw. I would definitely be changing out my fuel filter after a few hours of run time after cutting into the fuel tank. But I have to completely disagree with the last post: never put any water into your fuel tank! Water is the biggest enemy of diesel engines, & if it is not perfectly dried & removed, any water which works its way up to the engine could destroy your fuel injectors, or worse the fuel injection pump. If enough water gets into a cylinder, it can destroy the engine compression altogether. I totally unnecessary risk.
Remember that diesel fuel has much more stable characteristics then gasoline. Gasoline has a much higher risk of flash fire from a spark, not so with diesel. Octane & Cetane ratings are very different. There is an extremely rare chance that you will catch diesel fumes on fire with a spark from a hole saw. I have many friends who were in the Navy, & not that I advise it, they used to brag about how they would throw out cigarette butts into open diesel 55 gallon drum containers. Not that this is a smart thing to do, but it shows just how stable diesel fuel is, & perhaps how unstable some Navy sailors are! Cheers.
 

Bob S

.
Sep 27, 2007
1,771
Beneteau 393 New Bedford, MA
Caution - for gasket material for any 'access ports' in fuel tanks should probably be Viton® rubber, due to the increasing 'mixes' / blends with 'bio-fuels'
Thanks for the update. I used Buna N as my gasket material based on compatibility http://www.coleparmer.com/Chemical-Resistance
I'll keep a look out for the gasket integrity each season I clean it.
I fabricated a port based on the Seabuilt Access Plate
http://www.seabuilt.com/about.php
I'm lucky to have a machine shop at my disposal and have worked in the trade for many years. I emptied the tank and cut the hole with a 6" hole saw. I had one but if you need to buy one they are quite expensive! I went slow and wasn't too concerned about the shavings because I was very careful to wipe down the insides of the tank afterwards. The chips fell to the middle of the tank and were easily picked up with a rag. Don't use a wet vac! I used absorbent sheets to wipe the inside then to cotton rags. You probably could use baby diapers. I was surprised at how clean my tank was. Each season I start with a cleaning and new fuel which gives me peace of mind.
 

RichH

.
Feb 14, 2005
4,773
Tayana 37 cutter; I20/M20 SCOWS Worton Creek, MD
The typical contaminant in 'bio-diesel' is oleic acid. Follow and cross match the compatibility data for Oleic acid & #2 diesel oil if you are experiencing noticeable softening or swelling in BUNA or neoprene.
 
Jul 18, 2017
5
Catalina 30 South Freeport
I just cleaned my 18 gallon aluminum tank today.(1985 cat 30)...took the tank out after pumping fuel out, less than 1 hour.
Purple cleaner (degreaser) and a carboy brush stolen from my home brew closet did the trick, washed 4 times, then flushed with garden hose for 10 minutes. I drained it and turned my vacuum from suck to blow on the fuel fill for about 1 hour. Tank is spotless, dry. I did unthread and remove all fuel pickup tubes, sending unit etc. What I had been dreading was actually quite easy.
 
Oct 9, 2008
1,739
Bristol 29.9 Dana Point
It may not be necessary to cut holes.

I'll tell my experience with bugs. It may be invalid regarding others, and/or a misperception, and I welcome a beating session :)

When I bought the boat 6+ years ago, I filled the tank and added Startron treatment.
Soon after, noticed junk in the Racor glass. Continued to change the filter on schedule, ignoring the junk and thinking it just a stain, as none of any junk came out when I drained the glass for filter change.
On one filter change job, decided to remove the Racor and clean it.
Loads of mudish coffee ground stuff in there. Never had engine running issues; I think because it only flows at .3 gph. Or about .64 ounces a minute. An under-filled tequila shot per minute. So no clogs. And this was with 2 mic filters.
I run the engine at least once a week. All season sailing.
Anyway, had the same issues next filter change. Maybe a hundred hours later. Cleaned it all up again.
Kept adding the Startron at each fuel fill up. Probably added more than needed.
Now, glass is clean. It's been 50 hours since last filter change/Racor cleaning. No bugs.
 
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Jan 11, 2017
68
Hunter 37c Kingston
I have three baffled compartments in my tank so this year I emptied and with the blower end of my shop-vac, gassed-off the tank through the hole for the fuel gauge.. I cut three six inch holes in my tank (one per compartment) using a shop-vac to clean drill cuttings as I worked. I then cut a set of six 3/8 inch thick backing crescents based on an 8 inch circle and 1/2 thickness (3/16 inch) lapped by one inch on the end of each crescent . I then drilled and tapped the backing plates for 3/16 stainless screws, 6 per crescent. I epoxied the screws into the threads and drilled corresponding holes in a 7 inch circle around the tank cut-outs. I cut three 8 inch circles of 1/8 inch aluminum for covers also drilled to match the hole for the screws. I epoxied the 3/8 inch crescents to the inside of the tank, cut and holed the gaskets then put nyloc-nuts on the exposed threads and tightened down the covers. So far so good. If you are going to clean years of crap out of the tank, the aluminum "sawdust", cleans up with the gunk. I do recommend changing out the filters but the fuel filters will clean out anything left after the tank cleaning. If it had been a gasoline tank, I would have filled it with water prior to drilling the holes but since it is diesel I just made sure I had good ventilation in the work area. One 24 inch fan on high speed. blowing fumes away from the drill as I figured the only ignition source could be the brushes on the electric drill. In the interest of safety you need to make up your own mind about the flammability of ambient temperature diesel. I used west system epoxy to glue stuff inside the the tank as they have a protocol for it. I thought of using loctite but they have left the words "diesel fuel" out of all their products.
To be fair I am retired and my time is only valuable to me. If I had one compartment to work on, and time was short, I think I might have purchased an inspection port with hinged backing plate but I am satisfied with the savings.
BobV
 
Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
Bob V... I would be interested in any pictures you have of your project. I have been wondering how to engineer the inside the tank backing plate for the cover. I assume the gasket is held down against the tank surface by the top plate and the through screws/bolts.
 
Jan 11, 2017
68
Hunter 37c Kingston
Hi John
You are correct that the gasket is sandwiched between the top of the tank and the 8 inch round top plate with 12 screw/bolts set equidistant at the seven inch circle. The boat is down in Virginia and I am back in Canada, it will be towards the end of October before I can put the photos together. I can describe the backing plate however as it seems you have a good visual sense of what was going on.
The 3/8 backing plate is made up of two semicircles. They are cut as a six inch circle on the inside of the arc and an 8 inch circle on the outside of the arc. Imagine the right hand semi-circle is exactly one half of the arc, the left hand semicircle is one inch longer on each end than the right hand one. If you were to lay them on top of each other to create a circle they would lap at each end of the semi-circle by an inch. I then marked both pieces at the overlap and put them in a vice and cut them with a hack-saw and a file, so that when they were put together the laps matched and I had a complete circle of the same thickness. Think shiplap but longer and in aluminum. I made up a template for drilling, out of door skin thick plywood and used that to mark all the holes in all of the parts of the ports including the tank. I then drilled the holes to be tapped, in a seven inch circle making sure that a hole was drilled through the lapped section at each end the holes at the lapped section were tapped like all the others but the hole in the semi-circle under the section touching the top of the tank was drilled large enough so that the screw/bolt would fit through the hole and thread into the upper semi-circle. When put together inside the tank all the screw/bolts are already epoxied in place and some epoxy is added to the screws at the joints and the lap was epoxied as well. This was to ensure that the screw/bolts would not turn when the nuts were applied. Once that epoxy was set, the screw/bolts were pushed up through the pre-drilled holes in the tank and the backing plate was epoxied to the inside of the tank. I'm not a really technical person so I went to NAPA and asked them for some gasket material that would be good for diesel and they sold me some heavy reddish orange rubber that I cut to size. I haven't tested it with the boat in motion so I will be keeping an eye on the gasket material until I know how it will hold up.
Please feel free to ask any specific question you like, if there is something I have not explained clearly enough.
BobV
 
Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
Thank you Bob.
As I understand what you identified, the backing plates are epoxied to the inside of the tank. You must of had to acetone clean the area where the backing plates are attached. Then the bolts stick up like studs and the top plate is placed over the gasket and onto the studs. Did you just secure with nuts or cap nuts?
 
Jan 11, 2017
68
Hunter 37c Kingston
Hi John
I think you have the the right picture
I used denatured alcohol to clean the aluminum epoxy bond not acetone. The nuts I used are called ny-loc. they look like a cap-nut but the domed section is open and there is a small nylon insert in the domed section that compresses around the bolt and stops vibration from allowing them to back off. There is a sheet of plywood suspended above my tank so I do not need to worry about snagging anything. If I was going to use a cap-nut I might think about a stainless lock-washer between the nut and the cover.
It is my understanding, and I could be proven wrong, that acetone will clean the aluminum too much and an unbonded layer of oxides could form between the aluminum and the epoxy whereas the chromate coating and any existing oxides will give you a better epoxy bond. The strength of the bond did not seem as important to me as the fact that it held the backing plate in place. It would be possible to put some permatex gasket compound on the backing plate to hold it in place until the nuts are tightened.
I hope this all helps you with your own ideas on how to get the backing plate in place. I will be interested in any variations you come up with. I figure that I did all three, six inch ports for less than the price of one four inch manufactured one.
Fair winds
BobV