Author Topic: Converting aft water tank to diesel on a 44  (Read 363 times)

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joel

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Re: Converting aft water tank to diesel on a 44
« Reply #6 on: January 07, 2021, 03:29:12 PM »
Burt,

Great idea!  Thanks!  I've done a crude re-draw of the diagram to incorporate it.  I added a return to the aft tank and isolated the Racor and pump, eliminating the 3 way valve.  I'll add valves at the manifolds.

FWIW I went back to the original drawings from Hylas.  They ran a return for the aft tank back into the supply line, so it never really returned to the tank.

Joel 
« Last Edit: January 07, 2021, 09:03:03 PM by joel »

burtpreston

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Re: Converting aft water tank to diesel on a 44
« Reply #5 on: January 07, 2021, 03:18:17 PM »
Hi Joel,
It looks like you are just planing on using the aft tank as a storage tank which can transfer fuel to the front "active" tanks" since you don't show a return line from the engine to the aft tank. The only issue is I don't know if you will be able to transfer fuel while the engine is running. You might be able to pull from the aft tank while returning to the front tanks, but you will need to monitor carefully at first to get a feel for how the tanks are emptying/filling.
One option to consider is moving the transfer pump and racor so the transfer pump pulls from the output of the supply manifold and pumps into the input of the return manifold. This would allow polishing the fuel from any of the three tanks. You would probably need to employ two three-way valves, one at each end of the transfer pump/racor circuit. This would also allow transferring fuel from any of the three tanks to any of the return tanks, which is helpful for winterizing or cleaning tanks.
Burt Preston
Exuberant
H44-83

joel

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Re: Converting aft water tank to diesel on a 44
« Reply #4 on: January 06, 2021, 05:00:24 PM »
Here is a drawing (done by a friend) of the fuel system.

the original plan for the 44 calls for the aft tank to be diesel, so I am going back to the original configuration and adding the second Racor and transfer pump.

joel

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Re: Converting aft water tank to diesel on a 44
« Reply #3 on: December 29, 2020, 07:47:10 PM »
Burt,

Thanks.  Our manifolds are on the port side at the forward end of the engine room.

I've ordered everything except the fuel fill and vent hoses.  I'm going to mount the new Racor, the transfer pump and a 3 way valve on a piece of starboard and mount that at the port aft end of the engine room. 

One important lesson - the threads on the Racor are SAE thread and take a special fitting you can get from Parker.

I've also ordered a sending unit to connect that tank to my fuel gauge.  Still lots of drilling and connecting to be done when it gets a little warmer in Annapolis.

Joel
« Last Edit: December 29, 2020, 07:50:42 PM by joel »

burtpreston

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Re: Converting aft water tank to diesel on a 44
« Reply #2 on: December 22, 2020, 05:15:48 AM »
We also converted our aft water tank to diesel and at the same time re-plumbed the fuel lioness. It accomplished a number of objectives.
Since we had a diesel generator, we added fuel pickups from all three tanks. The original Hylas system had a single pickup that provided fuel to both the main engine and the genset. Adding the second pickup to each tank was easy because the tanks already have threaded tank inlets. Just need to solder a tube to an elbow and cut to the correct length. For this second pickup we ran the tube to the bottom of the tank which proved very valuable. When the genset ran it was pulling fuel from the very bottom of the tank, so it was constantly taking any bad stuff in the tank, unlike the main engine pickups which were a little over a 1/2inch off the bottom. If the genset fouled it isn't a crisis.
Also by having a pickup on the bottom we can easily check the quality of fuel in the tank because we also added a transfer pump and racor filter and plumbed them to allow polishing the fuel in each tank separately. When you take on fuel just run it through the polisher for a few minutes and then check the racor for water or other pollutants.
Also, the pickup on the bottom allows emptying the tanks completely. Generally we switch tanks when we get down to the bottom 20%. That leaves a lot of fuel unused. With the transfer pump we can completely empty each tank.
One other addition was a hand pump in one of the pickups, just a simple squeeze bulb like in the dingy fuel line. This makes changing fuel filters very easy. Change the racor filter and refill with the squeeze pump. Then change the engine mounted fuel filter and refill with the squeeze pump. Some people don't like using these hand pumps because they can fail, but if the hand pumps are in a genset pickup or an extra pickup it doesn't really matter. Also, if you plumb with imagination the hand bulb pump can back feed the other pickups and blow out any dirt at the inlet to the pickups.
Also, when re-plumbing you can arrange it so that both the main engine racor filter and the gender racor filter can feed the main engine. Then by throwing a valve or two you can switch filters while underway.
Finally, we used this project to relocate the manifolds from the area of the nav station floorboards to the area above the two fuel tanks just forward of the companionway steps. The floorboards are much easier to access in this area, so doing any of the above is simplified.
If anyone wants a schematic of our fuel system please send me an email at burtpreston50@gmail.com.
After 40,000 miles the tanks were very clean and we never had a problem with fuel, despite spending three months each year in the Bahamas.
Burt Preston
Exuberant
H44-83

joel

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Converting aft water tank to diesel on a 44
« Reply #1 on: December 14, 2020, 08:57:44 PM »
The aft water tank has not been used in years.  I want to convert it to diesel.

My plan is to change the deck fill so it says "diesel' along with the fill and overflow hoses, add a new hose, racor and transfer pump to transfer fuel to the center under-deck tanks.  I'd have a 't' after the racor to run to the manifold in case of transfer pump failure.  The current tanks have a single fill, so if one fills it would overflow into the other.

Suggested improvements? Critique?

Joel
Atlantis
Hylas 44 #66

 

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