The Old NP List – Fuel & Water Tankage
To manage the list on IBIS (NP-43, hull 24) we installed a fuel and a water transfer system. The fuel system has not turned out to be adequate. It only transferred some 40 gallons an hour and the engine needs to be shut down during transfer. There is also a complected valve setting for transfer/engine operation. The water transfer system requires some valve settings, but the transfer rate is much fast, about 10 gallons per minute, and can be accomplished while underway. Another tankage problem is the sight gages. You can't see the water level and the way the fuel sight gages are plumbed doesn't speak for accuracy.
In search of list control and improved fuel and water management, we've installed Wema S3U (26”) fuel/water sensors ($50 each) in each tank (4) and a CruzePro TL60 ($215) digital tank level gauge on the dash. The gage monitors three tanks and provides a programmable alarm (85db) for low and full settings. We now know exactly how much fuel (gallons or litters) is in each tank at all times. We also have an external buzzer in the cockpit to tell us when each fuel tank is full, which can be very handy at noisy fuel docks. With the TL60 gage monitoring the third tank, we use a toggle switch to read the port or starboard water tank.
To transfer fuel, we are taking out the old transfer system and installing a new larger (1.25”) cross-feed line between the fuel tanks. In this line we're installing a reversible, high-speed diesel fuel pump (15/20 gallons per minute). With a spring-loaded, momentary toggle switch on the dash, we can transfer any amount of fuel anytime by holding the switch in the direction (port or starboard) of desired flow while monitoring both the fuel levels on the TL60 gage.
One other small fuel problem we've encountered is the fuel feed to the Hurricane heater. Instead of cutting a new hole in the port tank and installing a separate pickup, the installer put a tee on the engine pickup to feed both the heater and the engine. We feel this contributes to our predominate port list. More fuel is being sucked out of the starboard tank than the port tank. In contrast, the starboard tank has two separate pickups, one for the engine and one for the genset. My recommendation is to have the factory cut four holes in each tank and cap any that are not used. Of course, being fiberglass tanks, any competent mechanic cut new holes in the tanks for you.
RESOURCES:
Wema USA, Inc.
15 NE 3rd Street
Fort Lauderdale, FL 33301
Local: 954-463-1075
Fax: 954-463-1270
info@wemausa.com
http://www.wemausa.com/index.htm
CruzPro Ltd.
13 Burgundy Park Avenue
Henderson 0612
New Zealand
Tel: 64-9-838-3331
Fax: 64-9-838-3332
info@cruzpro.com
sales@cruzpro.com
www.cruzpro.com
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List
Another suggestion on this issue is the one we have adopted aboard the XXIV VII.
I set the tank shutoffs/returns to feed and return fuel to main eng from port tanks only and feed kabola and genny from stb tank separately. After an 8 hr run followed by a day or so on the hook , we stay pretty level. Equalizer valves are shut.
As for water, we feed off one tank at a time and as soon as the boat shows any sign of a list, the automatic ships level indicator (April) engages the manual anti-list mechanism (Me) to switch tanks.
Fool proof system as long as manual anti-list mechanism is not on a bit of a tilt. ( which can happen occasionaly).
List Correction
For further information on the lists caused by water tank imballances please see Arn Ditmar's (43028) post about check valves in the water lines. We have started doing this on newer boats and it seems to work perfectly.
http://www.northpacificowners.com/?q=node/79
Fuel Ballancing:
I think the best way to keep the fuel ballanced is to keep the equalization valves closed. I then draw and return to one tank at a time. The boat uses little fuel so you can usually run on one tank all day and the other the next or even switch every couple days. Switching tanks is fast.
Other people disagree with me and find that drawing from both tanks and returning to both is the way to go. This is; however, more difficult to get right. It is very difficult for us to make the fuel lines draw and return to each tank with exactly the same flow as it doesn't take much to make it different. Some boats are better than others for this. If your boat needs adjusting and you prefer to draw and return to both at once you can correct this by seeing which tank consistently ends up with more fuel in it. Once you know this slowly close the return valve to that tank while leaving the return valve to the other tank fully open. After some cruising time and slow adjustments you will be able to get them to draw down evenly.
We always recommend keeping the equalization lines closed unless you obviously have way more fuel in one tank than the other and you know the fuel will flow to the low tank. The problem with leaving them open is if you load the boat and it has even a slight list the fuel will run from the high tank to the low tank making the list worse.
I hope this helps!
Trevor
North Pacific Yachts Inc.