Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 04-05-2009, 20:02   #1
Registered User
 
redcobra's Avatar

Join Date: Mar 2009
Location: Towson, MD Chesapeake Bay
Boat: Pearson 39 Yawl "ZigZag"
Posts: 516
Fuel Tank Size

I am repowering and this also requires a new diesel fuel tank. The old tank is a 30 gallon tank. The engine will burn about 1-1.25gph at 7 knots. My initial thought was to go with a 30 gal tank again, however I have room for up to 50 gal. Previously I used about 25- 40 gallons a year.
I mainly cruise the Chesapeake Bay, but may venture into the Delaware Bay. Possible circum nav around the DelMarVa, remote possibility of a trip to Bermuda (dream dream).
Whadda u tink? 30, 40, 50?
Thanks

ps: 39 ft Pearson Yawl with a 4 cyl 38hp diesel.
__________________

__________________
redcobra is offline   Reply With Quote
Old 04-05-2009, 20:16   #2
Moderator Emeritus
 
David M's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: San Francisco Bay
Boat: research vessel
Posts: 10,150
There are two things you need to consider but in your case it probably wont matter much at all.

The first is your change in trim. This is calculated by getting the MT1 figure for your boat. MT1 is the moment it takes to change your trim one inch. The further you put the increased weight away from the LCB, or location of center of buoyancy, the greater the weight will affect your trim.

The second item is moment of inertia. The greater the mass is placed away from the boats center of gravity, the greater the tendency your boat will have to pitch.

In your case you are only adding 7 pounds per gallon times 20 gallons or a weight of 140 pounds plus the weight difference of a larger tank. As I said, its pretty much not worrying about for a 39 foot boat.

I say go for for the 50 gallon tank.
__________________

__________________
David

Life begins where land ends.
David M is offline   Reply With Quote
Old 04-05-2009, 20:41   #3
Writing Full-Time Since 2014
 
thinwater's Avatar

Join Date: Nov 2008
Location: Deale, MD
Boat: PDQ Altair, 32/34
Posts: 4,329
A personal call.

Quote:
Originally Posted by redcobra View Post
I am repowering and this also requires a new diesel fuel tank. The old tank is a 30 gallon tank. The engine will burn about 1-1.25gph at 7 knots. My initial thought was to go with a 30 gal tank again, however I have room for up to 50 gal. Previously I used about 25- 40 gallons a year.
I mainly cruise the Chesapeake Bay, but may venture into the Delaware Bay. Possible circum nav around the DelMarVa, remote possibility of a trip to Bermuda (dream dream).
Whadda u tink? 30, 40, 50?
Thanks

ps: 39 ft Pearson Yawl with a 4 cyl 38hp diesel.
You can sail. You can motor everything. I've done the Delmarva trip 4 times now (some discussion on my blog, below) and I found that the ability to motor as much as 100 miles really cuts down on the need for marina hopping, should the wind die. The longest run between fuel stops can be Cape Charles to Lewis to Cape May, depending on draft and weather, which is over 150 miles. So, perhaps 30 gallons is a good minimum. More likely, you can fuel in Ocean City or Chincoteague if the wind is lacking.

The counter argument, you mentioned; your fuel is going to get very old, which can bring its own pain. You cannot leave the tank 1/2 full, unless you really want polymerization/oxidation sludge and biological contamination issues.

Clearly, the best answer is more tankage and more trips!

PS. I am looking at uping the tankage on my new boat - Bermuda is calling... loudly!
__________________
Gear Testing--Engineering--Sailing

Writing full-time since 2014.
Bookstore:http://sail-delmarva.blogspot.com/20...ook-store.html
thinwater is offline   Reply With Quote
Old 04-05-2009, 20:50   #4
Moderator Emeritus
 
Pblais's Avatar

Join Date: Mar 2003
Location: Hayes, VA
Boat: Gozzard 36
Posts: 8,700
Images: 15
Send a message via Skype™ to Pblais
The fuel tank can't be too big. It's why you are a cruiser. You do have to be practical as far as space and displacement. We used to have 60 gallons on the last boat with a 35 HP engine. I think if you can handle the extra weight then go for it. No one ever ran out of fuel because the tank was too big. The engine side of things is not unimportant. Hope to be heading up the Bay mid month in June so look for Bright Eyes.
__________________
Paul Blais
s/v Bright Eyes Gozzard 36
37 15.7 N 76 28.9 W
Pblais is offline   Reply With Quote
Old 04-05-2009, 21:52   #5
Senior Cruiser

Cruisers Forum Supporter

Join Date: Jul 2005
Boat: Outbound 44
Posts: 4,569
How about installing a 35 gal tank and 15 gal tank. You can use the 15 gal tank for your normal sailing and avoid stale fuel. When you plan on longer trip, fill them both.

Paul L
__________________
Paul L is offline   Reply With Quote
Old 05-05-2009, 06:20   #6
Registered User
 
markpj23's Avatar

Join Date: Nov 2005
Location: Black Hills, SD
Boat: Now Boatless
Posts: 1,148
Images: 47
I'd opt for the bigger tank - and since you're doing a new installation add a polishing loop!
__________________
Mark
markpj23 is offline   Reply With Quote
Old 05-05-2009, 19:43   #7
Registered User
 
redcobra's Avatar

Join Date: Mar 2009
Location: Towson, MD Chesapeake Bay
Boat: Pearson 39 Yawl "ZigZag"
Posts: 516
polishing loop?

polishing loop?

Just looked it up. Is that really necessary for a sailboat with a new tank? The old tank was 33 years old and I never had a fuel problem.

Always used a Racor external filter/separator
__________________
redcobra is offline   Reply With Quote
Old 05-01-2016, 15:25   #8
Registered User

Join Date: Aug 2013
Posts: 37
Re: Fuel Tank Size

To: MarkPJ23
Join Date: Nov 2005
Location: Black Hills, SD
Boat: Now Boatless
Posts: 1,148

"Boatless" ... so sad
__________________
Formosa46AK is offline   Reply With Quote
Old 05-01-2016, 17:29   #9
Senior Cruiser
 
FSMike's Avatar

Cruisers Forum Supporter

Join Date: Aug 2009
Location: Bahamas/Florida
Boat: Solaris Sunstar 36' catamaran
Posts: 2,654
Images: 5
Re: Fuel Tank Size

A larger tank might be more desirable to a prospective buyer should you decide to sell.
Or, of course, if you were to change your sailing area/habits.
__________________

__________________
Sail Fast Live Slow
FSMike is offline   Reply With Quote
Reply

Tags
fuel, fuel tank

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
Endeavour 40 Fuel Tank engcon Construction, Maintenance & Refit 9 16-02-2016 07:37
fuel tank emptied motion30 Engines and Propulsion Systems 1 17-03-2009 02:27
newby question about tank size escapeartist Monohull Sailboats 9 22-10-2008 17:44
Fuel Line size Charlie Engines and Propulsion Systems 8 28-06-2008 13:18
Endeavour 40 Fuel Tank Size engcon Engines and Propulsion Systems 4 16-05-2007 19:45



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 09:57.


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.