Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 30-05-2016, 02:49   #1
Registered User

Join Date: Oct 2009
Location: Pacific NW and Mexico
Boat: Oyster 435
Posts: 134
Flexible Diesel bladder plumbing?

Hi all
We have just removed one of our holding tanks and are considering installing a flexible diesel bladder to increase our motoring range offshore. This tank would only be used a couple of times a year so Im not too worried about chafe from constant use. Flexible is looking like the way to go because we need the space for storage as well. The main issue is how to plumb it.
Nauta says It can be plumbed without a vent because it expands as filled and collapses as emptied. With 50Gal of fuel though do I need to worry about too much pressure from daily thermal expansion? What about pressure from it being tossed around at sea?
I plan to fill it via some sort of transfer pump plumbed from my main tank. Once the main tank is drawn down enough I'd pump the bladder empty. The solid state pumps are way cheaper(albeit way slower) but I cant figure out if they can be reversed by changing the polarity... If I spend the big bucks and buy a real reversing transfer pump do I need to worry about pressure blowing up the tank if I forget to keep an eye on the transfer?
Who's set up something like this?
Thanks
Gary
__________________

__________________
gpeacock is offline   Reply With Quote
Old 30-05-2016, 03:41   #2
Senior Cruiser

Cruisers Forum Supporter

Join Date: Jul 2005
Boat: Outbound 44
Posts: 4,575
Re: Flexible Diesel bladder plumbing?

I used a stock fuel pump. Hooked it up with quick release hydraulic lines. To reverse I unhooked the pump and reattached the other direction using the quick releases.
__________________

__________________
Paul L
http://svjeorgia.blogspot.com
Paul L is offline   Reply With Quote
Old 30-05-2016, 06:08   #3
Registered User

Join Date: Oct 2009
Location: Pacific NW and Mexico
Boat: Oyster 435
Posts: 134
Re: Flexible Diesel bladder plumbing?

Quote:
Originally Posted by Paul L View Post
I used a stock fuel pump. Hooked it up with quick release hydraulic lines. To reverse I unhooked the pump and reattached the other direction using the quick releases.
Hey good idea... I didnt know that quick release fittings also had shutoff valves built into them... Not much fuel mess I guess.
Just one fitting on your bladder? No air vent?
Thanks
Gary
__________________
gpeacock is offline   Reply With Quote
Old 30-05-2016, 06:22   #4
Registered User
 
SteveSails's Avatar

Join Date: Jan 2014
Location: St Michaels MD
Boat: F&C 44
Posts: 125
Re: Flexible Diesel bladder plumbing?

I installed a 25gal Nauta bladder last year. Sprung for the Groco reversible transfer pump and I'm glad I did, makes quick work of filling or emptying the bladder. I did installed a vent line T'eed to the main tank vent, if the bladder overfills then it would just run out the vent and back to the main tank. From what I remember of the Nauta instructions they require a vent for diesel but not for water use.

If you do install a transfer pump add a T with a hose so you can transfer from or to a jerry can. Very handy when it's too rough and wet on deck to open the fuel fill.

Steve
__________________
SteveSails is offline   Reply With Quote
Old 30-05-2016, 10:13   #5
Marine Service Provider

Join Date: Sep 2011
Location: California
Boat: Alerion Express 38 Yawl
Posts: 269
Re: Flexible Diesel bladder plumbing?

I added two 100 liter (26 gallon) Vetus tanks to a race boat that I was bringing home from Hawaii. The bladders sat on the inside of the hull with no permanent plumbing. I think there was a fuel fill inlet on the top center of the tank, which was not ideal, but also not used very often. The fuel outlet was a 5/8" barbed fitting to which I attached a few feet of hose, and then corked off the bitter end.

I used an impeller pump from Jabsco that pumped about 5gpm to pump the fuel into the main tank, using a longer piece of small diameter fuel hose. There was no vent, no permanent plumbing, no spillage, etc. Very simple. When I had pumped the tank dry, the transfer pump made a different sound and I turned it off, plugged up the discharge line, and waited until I would need the other bladder (several days later). No vent required.

I could roll up the empty bladders and store them off the boat. They want to assume a pillow shape, so you need to have enough space so they can "fluff out" to their normal shape.

As a cautionary note, the only time I did this was in 1983 when the 67' boat I was captain of lost her 10,400# keel in 12,000' of water, about 300 miles north of Kauai. The boat did not capsize, thankfully, and we were able to power back to Waikiki, although we came close to rolling over on a number of occasions. Had we rolled over with the unrestrained bladders full of fuel, it would have made a terrible situation just that much more terrible, but it's not easy to restrain a full bladder of fuel, unless you have a securely bolted "top" to it's containment area.

Chuck Hawley
Former boat captain of "Charley", Holland 67
Winner of the First to Finish, Transpac, 1983.
__________________
Chuck Hawley is offline   Reply With Quote
Old 30-05-2016, 10:38   #6
Senior Cruiser

Cruisers Forum Supporter

Join Date: Mar 2014
Location: Anacortes
Boat: previous - Whitby 42 new - Goldenwave 44
Posts: 1,735
Re: Flexible Diesel bladder plumbing?

I looked into bladder tanks as an option for increasing my fuel capacity on my sailboat. I remember that every manufacturer specifically said not to put a bladder tank inside of any boat. I would be very cautious. The fellow who did it one time on a special case basis is one thing. Doing it permanently is quite another. I know it wouldn't pass a competent survey.
__________________
exMaggieDrum is offline   Reply With Quote
Old 30-05-2016, 11:28   #7
Registered User

Join Date: Sep 2008
Location: Washington State, North Cascades
Boat: Valiant 40
Posts: 54
Re: Flexible Diesel bladder plumbing?

Our boat has a rigid bladder mounted inside the original metal fuel tank. It fits the tank perfectly. We have never found any sign of any condensation inside this tank. It has been in the boat at least 12 ywEA. SO FAR SO GOOD.
__________________
bongo is offline   Reply With Quote
Old 30-05-2016, 14:03   #8
Senior Cruiser

Cruisers Forum Supporter

Join Date: Jul 2005
Boat: Outbound 44
Posts: 4,575
Re: Flexible Diesel bladder plumbing?

Quote:
Originally Posted by gpeacock View Post
Hey good idea... I didnt know that quick release fittings also had shutoff valves built into them... Not much fuel mess I guess.
Just one fitting on your bladder? No air vent?
Thanks
Gary
One bladder fitting and no vent. The bladder was in a somewhat vertical area surrounded by anti-chafe outdoor carpet. In this configuration it would only fill to about 85 or 90% of Max spec, so I didn't feel it needed venting.
T
__________________
Paul L
http://svjeorgia.blogspot.com
Paul L is offline   Reply With Quote
Old 30-05-2016, 18:26   #9
Registered User

Join Date: Jul 2015
Location: Guelph ON Canada
Boat: Morgan OI 37
Posts: 72
Re: Flexible Diesel bladder plumbing?

I have a 25 gallon flexible Nauta diesel tank for sale will sell for $175.00 shipping incl. to Canada / Continental US Like new condition
__________________
BobLoucks is offline   Reply With Quote
Old 30-05-2016, 18:33   #10
Registered User

Join Date: Oct 2009
Location: Pacific NW and Mexico
Boat: Oyster 435
Posts: 134
Re: Flexible Diesel bladder plumbing?

Quote:
Originally Posted by BobLoucks View Post
I have a 25 gallon flexible Nauta diesel tank for sale will sell for $175.00 shipping incl. to Canada / Continental US Like new condition
Im interested. Ive PM'd you
__________________

__________________
gpeacock is offline   Reply With Quote
Reply

Tags
diesel, plumbing

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale: Diesel fuel bladder 25 gal vtsailguy Classifieds Archive 5 24-08-2015 06:26
Diesel bladder tank borvaprops Construction, Maintenance & Refit 12 11-02-2015 16:49
Fuel Bladder for an Interim Diesel Tank Patrick_DeepPlaya Engines and Propulsion Systems 20 06-02-2014 14:22
For Sale or Trade: Vetus 42 Gallon Flexible Water / Waste Bladder thesparrow Classifieds Archive 1 15-03-2011 10:11
Plumbing Fill for BOW Bladder Tank witzgall Construction, Maintenance & Refit 3 26-08-2009 06:53



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 10:05.


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.