371 - installing a bigger dieseltank

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installing a bigger dieseltank

Printed From: myHanse.com
Category: Hints & Tips
Forum Name: 371
Forum Description: 371 Hints and Tips
URL: https://www.myhanse.com/forum_posts.asp?TID=9006
Printed Date: 27 March 2026 at 03:29
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Topic: installing a bigger dieseltank

Posted By: scarab
Subject: installing a bigger dieseltank
Date Posted: 05 May 2015 at 19:53

Hi,

Due to offshore sailing plans ( sailing to Guadeloupe ) there are some things that have to be taken care of on my Hanse 371.

One of the things I'am considering is fitting a larger diesel tank.

I have the 3 cabin version.

I'm thinking of changing the SB cabin into a technical area with extra storage

fascilities.

Has anybody experience with such a conversion ?

Greetz,

Koen

Replies:

Posted By: samuel
Date Posted: 06 May 2015 at 08:15

You have suggested a bigger tank but In case you consider the option of a reserve tank ( like I did) be aware that the fuel goes to the injectors but a fair quantity byepasses them & goes back to the tank.
i only have a Volvo MD2020 but the amount of fuel returning is quite large.
I had 2 full tanks & started by running on the reserve. The engine faltered & fuel came out of the main tank overflow as that tank was already full. My previous experience of diesel engines made me believe that there would only be a dribble of fuel returning so I carelessly ignored it.
So the point is that the easiest option would be a reserve tank but one would need to devise a "T" junction suitably valved to make sure that the return fuel went back to the tank in use. the reserve tank could also have its own pre filter which could be usefull if one filter clogged

The reason for the reserve tank was so I could run on white fuel in Belgium as they have a problem with boats from UK using red. they have changed their stance whilst the EU challenges the UK in court so I have not proceeded further.

A reserve tank also allowed me to put the storage further forward & lower down than loose cans stored in the stern locker. Every thing seems to get stored in the aft end of modern boats & this spoils the trim on a small boat like mine if over done

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Daydream Believer- Hanse 311- No GBR9917T- Bradwell Essex

Posted By: gertha
Date Posted: 06 May 2015 at 08:24

Not for me to advise on a larger tank as do not have a 371. However can help a bit on fuel usage and storage.
Have sailed Carib and back 2 times, we never used much fuel; your 80 lts would be more than enough; but I am a bit of a sailing man and would rather drift and wait for wind.
The Hanse will sail in light winds so the traditional advise on fuel used is for heavier boats that some people use for offshore work.
For my money 4 may be 5 Jerry cans in reserve is the max reserve I would take; these may have to be strapped to lifelines which is not elegant ;but is what a lot of boats do. A small 12 volt in line pump run off 12 volt socket is easiest way to transfer fuel at sea
Keeping reserve in cans helps to keep the diesel bug at bay; this is a permanent problem I have on the 140 lts that the 370 has.
Spend any money saved on fuel tank improving sails for light down wind work.

Posted By: samuel
Date Posted: 06 May 2015 at 11:28

Gertha
So, presumably, you never use the engine for charging ( unless motoring)

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Daydream Believer- Hanse 311- No GBR9917T- Bradwell Essex

Posted By: gertha
Date Posted: 06 May 2015 at 19:46

Samuel,
Historicly, we charge 20 mins every 4 hours, so 2 hours per day. Engine at 1500 rpm is about 1.2 lts per hour.
This about 2.5 lts per day.
Max off shore is 22 days so aprox lts is 60, however the odd motor for 6 to 12 hours ramps the batterie to full, as a result we have never used 100 lts on any leg of a trans atlantic sail.

I can only speak from my own experience; the 140 lts in the tank has never dropped below 50 lts on the two atlantic circuits we have sailed.

I now sail with a duogen so charging is zero; but for the most rent trip with duogen we lost a blade on the prop so motoring was not an option.
Bermuda to Azores in 13 days with 2 days on a search.

I use more fuel chasing tides and ports than I ever do off shore.

5 in the eveining with a foul tide and 30 miles to go, the engine is on for 5 hours to make 6 knots, full speed.
Heaven forbid the pub would be closed if we did not fire up our Japenes friend.

Off shore with 1500 miles to go we just wait for the wind, and arive a bit later; if the gribs show some wind we may may moter for 12 hours to try and find it; but not normaly worth it.

Posted By: scott
Date Posted: 06 May 2015 at 22:52

Hi Gertha -

I'm curious about your charging schedule. Why 20 minutes every four hours, instead of just doing it for two hours once a day? I'm interested if there's any trade-offs you've learned.

Thx!

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Scott
Sailing Mer, Hanse 415, Hull #85
Seattle

Posted By: scarab
Date Posted: 07 May 2015 at 15:26

I was thinking in replacing the current tank with a much larger ( Vetus 220 liter ) fuel tank.

Don't think that I prefer to motor but when things go wrong with the mast / sails / rigging

and you're in the middle of the Atlantic it's good to have options.

Also with all electronics working + lights + fridge even my upgraded battery bank ( 2 x 220 amp )

will need to be charged.

I have not yet adressed this side of the upgrade but

I might consider a windgenerator + 1 big swivel mount solarpanel.

As I already mentioned to make room for the larger fuel tank and create room for extra storage I will have to sacrifice the sleeping quarters.

The first owner ordered this 371 with 3 cabins.

i really appreciate your support on this matter.

Greetz,

Koen

Posted By: JesperBergsjo
Date Posted: 07 May 2015 at 15:59

Have you upgraded your Alternator with a smart controller or a Alternator to battery charger? If not, this is a must since the crappy Hitachi Alternator delivered as standard with 3YM30 will not charge more than 13.5-13.8V when the batteries will require 14.4 (normal sealed). I made that change several years ago an now enjoing 3x better chargíng -> 1/3 engine time for same Ah....

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Jesper

Posted By: scarab
Date Posted: 07 May 2015 at 18:52

My engine is a Volvo Penta MD2030 / 29ps. I have a Sterling Advanced 4 step alt regulator.

Posted By: JesperBergsjo
Date Posted: 08 May 2015 at 08:35

Great!

Then you have the best controller avalible. Maybee you should consider improving the cooling of your engine room with a fan. On my Yanmar/Hitachi the hi temp for the alternator was trigged after some 30 min of full charging.

Regaring your fuel tank upgrade - there is plenty of room in the original area so there should not be any problem to have some one making you a new fuel tank >150l that fits under the bed. It can be extended both to starboard and forward (the original tank is designed to fit in the 2-cabin version where the wall between the cabins is moved 20 cm starboard).

Maybee you should consider adding a 3rd battery. In my 371 (now sold) I had 3x115 + 1x75 (starter) in the original pisition - only changed the hatch to a bigger size.

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Jesper

Posted By: gertha
Date Posted: 08 May 2015 at 08:57

Scott,
Charging batteries is a grey art, no one really understands it.
However a 2 hour block will not put in the charge that a 6 x 20 min will, basically batteries only accept a charge when they are about 75 % , the 2 hour charge will mean you are trying to charge the batteries at 90% at which time far more time is needed to charge batterie relative to charge accepted by battery.
In addition we change shift every 4 hours , so no one has to suffer with 2 hours of engine when they are off, we start the engine 10 mins before shift change , this wakes some one up and turn off 10 mins after at which time the off person is ready for a kip.
Finally a 20 min boost prevents the battery dropping to far, so if a fault developed we know early and can find fault or shut systems down to preserve a full battery; if you leave 22 hours and a fault happens your battery will be flat or near.

Posted By: iemand
Date Posted: 08 May 2015 at 11:43

Hello,

if I would go on Bluewater cruising my first choice would be a water generator. Since watt&sea are not cheap a friend of mine choose this model, which is in a way a "non proffessional" product but he is very happy with the result:

http://sailnsea.myesell.com/index.php?target=products&product_id=8630

Sailing with 6-7,5 kn he really gets 8-15 Amp.

Maybe worth to look at....

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Hanse 312 MJ 2004 - Hanse 370e MJ 2007

Posted By: scott
Date Posted: 08 May 2015 at 13:58

Thanks for the explanation, Gertha - that makes sense - I hadn't thought of how it might work with a watch schedule

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Scott
Sailing Mer, Hanse 415, Hull #85
Seattle

Posted By: scarab
Date Posted: 11 May 2015 at 19:40

Jesper,

What is the best way to cool down the engine room ?

Koen

Posted By: Interlude
Date Posted: 12 May 2015 at 07:44

Re the suggestion that a larger tank could be made wider, bear in mind that the fuel takeoff needs to be located centrally to minimise the chance that it will suck air when the boat is heeled, and the minimum fuel capacity is limited by this. I discovered that a 1/3 full tank allowed air into the line when heeled about 10 degrees. Ideally the tank should not have a flat bottom!

Also, a single larger tank needs to be kept fairly full to minimise condensation allowing water in fuel, whereas several small tanks give more flexibility. But the return needs to be switched with the feed, and the fuel in the reserve tank will not be polished (filtered) by the return action.

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Interlude 342#241