Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 07-10-2012, 15:29   #31
Registered User
 
Agape39's Avatar

Join Date: Jul 2012
Location: Hollywood, Fl
Boat: Corbin39
Posts: 138
Quote:
Originally Posted by DeepFrz
It could also depend on whether the tank was built by a tank fabricator following all the requirements for a fuel tank or if it was just built by a local welder who knew nothing about building fuel tanks.
The welder that built mine builds military spec tanks. And yes it costs more to weld aluminum but that is my point, why use aluminum when you can use a thinner 316 stock and have it built cheaper with next to no corrosion issues as with aluminum? I've replaced steel and aluminum tanks with poly or stainless more than once or twice. And I do agree than installation of an aluminum tank is critical on whether it will stand up to the harsh environment.
__________________

__________________
Agape39 is offline   Reply With Quote
Old 07-10-2012, 16:04   #32
Senior Cruiser
 
DeepFrz's Avatar

Cruisers Forum Supporter

Join Date: Mar 2006
Location: Winnipeg
Boat: None at this time
Posts: 7,930
Re: Fiberglass Diesel Fuel Tank

Quote:
And I do agree than installation of an aluminum tank is critical on whether it will stand up to the harsh environment.
This is also true of a stainless tank. Or any metal tank for that matter. The care for metal tanks of any kind is the same. Keep the water out and keep them dry outside as well.
__________________

__________________
DeepFrz is offline   Reply With Quote
Old 07-10-2012, 18:30   #33
Nearly an old salt
 
goboatingnow's Avatar

Cruisers Forum Supporter

Join Date: Jun 2009
Posts: 13,649
Images: 3
I'm now firmly of the belief that good quality custom plastic tanks are best. I use Tektanks in the UK, but I'm sure there are many.


Dave
__________________
Check out my new blog on smart boat technology, networking and gadgets for the connected sailor! - http://smartboats.tumblr.com
goboatingnow is offline   Reply With Quote
Old 07-10-2012, 18:35   #34
Resin Head
 
minaret's Avatar

Cruisers Forum Supporter

Join Date: Aug 2007
Location: Seattle WA
Boat: Nauticat
Posts: 7,201
Images: 52
Re: Fiberglass Diesel Fuel Tank

Quote:
Originally Posted by goboatingnow View Post
I'm now firmly of the belief that good quality custom plastic tanks are best. I use Tektanks in the UK, but I'm sure there are many.


Dave

Why is a plastic tank better than a profesionally built integral glass tank? Cheaper, maybe, but better?
For large tanks they often aren't even cheaper, due to the baffling making the tank impossible to mold.
__________________
minaret is offline   Reply With Quote
Old 07-10-2012, 19:12   #35
Nearly an old salt
 
goboatingnow's Avatar

Cruisers Forum Supporter

Join Date: Jun 2009
Posts: 13,649
Images: 3
Quote:
Originally Posted by minaret

Why is a plastic tank better than a profesionally built integral glass tank? Cheaper, maybe, but better?
For large tanks they often aren't even cheaper, due to the baffling making the tank impossible to mold.
These are custom tanks , not moulded.

Why are they better.

1. I'd never have integral tanks or anything, if i could, Any fault requires tearing the boat apart. Some faults are virtually unrepairable.

2. If I had a choice all components of the interior should fit through the companionway and hatch. Including the tanks. Hence more smaller tanks , rather then one huge one.

3. Done properly plastic tanks are indestructible and suffer none of the problems of aluminium or stainless

4. With specific plastics, such tanks are totally impermeable , unlike fibreglass.

Dave
__________________
Check out my new blog on smart boat technology, networking and gadgets for the connected sailor! - http://smartboats.tumblr.com
goboatingnow is offline   Reply With Quote
Old 07-10-2012, 19:24   #36
Registered User

Join Date: May 2008
Location: SW Florida
Boat: Bristol (Alden) 35 Sloop "Zephyr"
Posts: 498
Images: 2
Re: Fiberglass Diesel Fuel Tank

I would never put an integral fuel tank in my boat. My boat has 2 integral water tanks, and they both developed cracks, and needed repair. Boat hulls can move a bit.

Speaking of glass tanks. I have been thinking of making a 8 gallon gas tank, for a vintage runabout I have. I have some 1/4" thick flat fiberglass panels, I was thinking of using. One side of the panels has gelcoat on them, the other raw glass.
Should the inside of a fg tank be gel coated?
__________________
over40pirate is offline   Reply With Quote
Old 07-10-2012, 19:37   #37
Registered User

Join Date: Feb 2012
Posts: 371
Re: Fiberglass Diesel Fuel Tank

SS fuel tanks are no longer USCG approved due to corrosion and failure. Aluminum is recommended---but coal tar epoxy coat the outside----progressive epoxy has this item. Plastic is OK but it needs to be crosslinked which is not very amenable to welding like the non-crosslinked which is what water tanks can be made from thus the x-linked needs to be rotomolded and can be quite expensive. Also inspection ports in plastic tanks is not always recommended due to the potential for leaks.

Long story short aluminum is usually the best choice. I think fiberglass tanks are good too but the issue with the new fuels has yet to be fully assessed.
__________________
Lojanica is offline   Reply With Quote
Old 07-10-2012, 20:17   #38
Resin Head
 
minaret's Avatar

Cruisers Forum Supporter

Join Date: Aug 2007
Location: Seattle WA
Boat: Nauticat
Posts: 7,201
Images: 52
Re: Fiberglass Diesel Fuel Tank

Quote:
Originally Posted by goboatingnow View Post
These are custom tanks , not moulded.

Which means they have welded baffles, an inferor method known for failure.



Why are they better.

1. I'd never have integral tanks or anything, if i could, Any fault requires tearing the boat apart. Some faults are virtually unrepairable.

Why would a fault require tearing the boat apart? Just install big inspection ports, it's easy and reliable in fiberglass. In fact most FRP tanks have the baffles glassed to the lid through the ports, so they already need to be big enough to work inside the tank with. And what sort of "fault" could possibly occur in a pro tank?


2. If I had a choice all components of the interior should fit through the companionway and hatch. Including the tanks. Hence more smaller tanks , rather then one huge one.

This is small boat thinking. For instance in my case I have 450 gallons of fuel tankage in two tanks. If you think you can fit a 225 gal. tank through a companionway you are confused. This is only an option on small boats with small tanks.


3. Done properly plastic tanks are indestructible and suffer none of the problems of aluminium or stainless

So far from true. I have seen legions of failed welds in plastic tanks of all sizes and builds, including cracks in very high quality molded tanks. FRP is much stronger and less brittle.

4. With specific plastics, such tanks are totally impermeable , unlike fibreglass.

With modern epoxy barrier coats rated for use in FRP fuel tanks there is no problem with modern fuel. I have built many and have never gotten a warranty claim, including integral tanks designed by Carl Schumacher and built in a 13 million dollar 77' ultralight, which I also built.


Dave



Integral tanks got a needless bad rep from some manufacterers poor execution back in the 80's and 90's. I have seen catastrophic failure of integral tanks that were just internally gelcoated, the fuel penetrated the hull layup entirely and it was a huge problem. When I build a glass tank I build in epoxy lam, glass the hull as well as the sidewalls and lid so the entire tank has substantial epoxy lam everywhere and the original hull lam is not exposed to fuel, and barrier coat the entire interior with 7-8 coats of 2000e. This sort of tank will never degrade or fail, short of the hull being penetrated in the location of the tank all the way through the extra tank lam. Highly unlikely since most tanks are situated above keel structure.
__________________
minaret is offline   Reply With Quote
Old 08-10-2012, 00:11   #39
Registered User

Join Date: Sep 2009
Location: Mackay,QLD, Australia
Boat: planning a approx 45ft cat
Posts: 3,651
Images: 3
Re: Fiberglass Diesel Fuel Tank

Quote:
Originally Posted by minaret View Post
Integral tanks got a needless bad rep from some manufacterers poor execution back in the 80's and 90's. I have seen catastrophic failure of integral tanks that were just internally gelcoated, the fuel penetrated the hull layup entirely and it was a huge problem. When I build a glass tank I build in epoxy lam, glass the hull as well as the sidewalls and lid so the entire tank has substantial epoxy lam everywhere and the original hull lam is not exposed to fuel, and barrier coat the entire interior with 7-8 coats of 2000e. This sort of tank will never degrade or fail, short of the hull being penetrated in the location of the tank all the way through the extra tank lam. Highly unlikely since most tanks are situated above keel structure.

Minaret,

I am with you here. Can't see a problem with a properly constructed intergral fibreglass. Easy to ensure large inspection ports.
__________________
downunder is offline   Reply With Quote
Old 24-05-2017, 09:45   #40
Registered User

Join Date: Feb 2009
Posts: 1,848
Re: Fiberglass Diesel Fuel Tank

I know this is a very old post but it is relevant to my current situation. I was able to remove the old steel tank from my port side with a Sawzall. I am planning on a fiberglass tank installed in three pieces and glass together and place period I have quite a questions about how to install fittings. Can anybody help?
__________________
motion30 is offline   Reply With Quote
Old 24-05-2017, 10:19   #41
Senior Cruiser
 
Roy M's Avatar

Cruisers Forum Supporter

Join Date: Feb 2007
Location: Southwestern Yacht Club, San Diego, CA
Boat: Searunner 40 trimaran, WILDERNESS
Posts: 3,042
Images: 4
Re: Fiberglass Diesel Fuel Tank

Sure. What are your questions?
__________________
Roy M is offline   Reply With Quote
Old 24-05-2017, 10:34   #42
Senior Cruiser

Cruisers Forum Supporter

Join Date: May 2013
Location: Oregon to Alaska
Boat: Wheeler Shipyard 83' ex USCG
Posts: 1,708
Re: Fiberglass Diesel Fuel Tank

Design your 3 piece tank with a lip so there's a large, solid overlap that allows a wide epoxy bond. When I built epoxy diesel tanks I put all the fittings on top. Usually all fittings mounted on a large metal plate, giving a large surface area for a good bonding and additional build up over the plate, close to the fittings to sandwich the plate for a strong, leak proof seal.
__________________
Lepke is offline   Reply With Quote
Old 24-05-2017, 11:14   #43
Registered User

Join Date: Feb 2009
Posts: 1,848
Re: Fiberglass Diesel Fuel Tank

Thanks for the response gentleman period I was going to build the tanks at a vinyl Ester when I Bond them together in the boat should I use epoxy? I have eight fittings that need to go in the tank I was going to use brass bulkhead fittings and bed them in and epoxy paste maybe fiberglass over them and drill a hole is this a good idea? Some are on the bottom side of the tank. Also would it be better to use a male or female mold in fabricating the tank
__________________
motion30 is offline   Reply With Quote
Old 24-05-2017, 22:57   #44
Registered User
 
Cyrus Safdari's Avatar

Join Date: Jul 2009
Location: St Augustine, Fla
Boat: 1967 Pearson 35
Posts: 126
Re: Fiberglass Diesel Fuel Tank

Quote:
Originally Posted by Annie in WA View Post
While our tank is small by many standards (62 gallons), a respected marine surveyor that I spoke to said the tank was too big not to have a baffle and baffles are difficult to fasten for plastic..
If baffles are your only issue, that is easily addressed: baffle balls

Surge Control Ball Baffles | Engineered For Enduranceā„¢ - Enduraplas

Large Baffle Ball for Tanks with 16" Lid STBBS35

Others just put sections of PVC pipe inside the tank. Stops the sloshing.
__________________
Cyrus Safdari is offline   Reply With Quote
Old 25-05-2017, 06:20   #45
Bailing as fast as I can.
 
GILow's Avatar

Join Date: Sep 2008
Location: Adelaide, South Australia
Boat: Swanson 42
Posts: 3,585
Re: Fiberglass Diesel Fuel Tank

The issue of adding fittings to fg tanks has been covered well in recent threads (< 1 year old). I don't know how to post the results of searches using this iPhone app but have a good search around and you will find them. Read them all because there were a couple of different approaches with the merits and pitfalls of each discussed at length. Good reading overall.
__________________

__________________
Very funny Scotty, now beam down my clothes.
http://www.swansonsailor.id.au
GILow is offline   Reply With Quote
Reply

Tags
diesel, fiberglass, fuel

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 11:13.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.