[Sentoa] NT 32 fuel polishing

Thu Dec 11 13:02:53 EST 2008

Jim,

Agree.  As I recall, the 330hp is rated at nearly 60gph fuel flow at WOT so 
there is a tremendous amount of filtered fuel returned to the tanks, 
effectively polished.  Seems to me the one issue not being addressed here is 
vital for a thorough cleaning of the tanks and that is access/inspection 
ports in the tank.  (I believe that ABYC regs prohibit them on the tank 
sides and they are inaccessible on the top of NT tanks.)  With a PORTABLE 
polishing system they allow thorough agitation of the fuel in the tank by 
directing the return flow around the inside of the tank.  I've been 
considering adding inspection ports but am concerned about the location of 
interior baffles.  I don't want to cut a hole in the tank directly over a 
baffle because that will prevent locating the inner flange.  Suppose the NT 
engineering dept. can provide that info or direct us to the tank 
manufacturer for a drawing.  I suspect Dan H could have answered that 
question.  Good thread.

Another issue relating to a polishing/transfer system is vessel trim.  When 
RILEY was built I ordered a blank piece of Starboard installed unobstructed 
on the center of the forward bulkhead so I could install an aftermarket 
system.  Haven't done it yet but eveytime I have to do the Nordic Tug 37 
shower shuffle to drain the shower I think how nice it would be to induce a 
2 degree port list to drain the shower.  I'm told the shower mold still has 
a flat pan.

Jim Moore
RILEY 37085

----- Original Message ----- 
From: "Jim Waskowich" <gybetalk at yahoo.com>
To: "South East Nordic Tugs Owners' Association (SENTOA)" 
<sentoa at lists.samurai.com>
Sent: Thursday, December 11, 2008 9:34 AM
Subject: Re: [Sentoa] NT 32 fuel polishing

Is FPPF recommended for the new common rail engines?  I think they cannot 
withstand any amount of water, in whatever form...  that said, it seems that 
fuel polishing would not add that much additional assurance of clean fuel, 
given that the tugs now have dual racors with water sensors along with the 
primary filter on the engine itself.  From the previous threads on the 
subject, it sounded like many of the guys were already running 2 micron 
elements in the racors.  And I know for the 380HP Cummons at least the elec 
fuel pump is pushing 50 GPH thru the system.  The engine burns 20 GPH WOT 
(and more like 3 the way most of us operate), so that's a lot of extra fuel 
that is getting "polished" just by normal operation.  I would be more 
concerned that as plumbed by the factory, the engine only ever draws on one 
of the 2 tanks.  The stbd tank only supplies the genset and so never sees 
any real flow.  Perhaps a project to allow selection of either the port or
 starboard tank would be time better spent?  Just a thought!

Jim Waskowich
Grand Adventure
NT37-142

--- On Thu, 12/11/08, Chuck Leavitt <cleavitt at whidbey.com> wrote:

> From: Chuck Leavitt <cleavitt at whidbey.com>
> Subject: Re: [Sentoa] NT 32 fuel polishing
> To: "South East Nordic Tugs Owners' Association (SENTOA)" 
> <sentoa at lists.samurai.com>
> Date: Thursday, December 11, 2008, 11:07 AM
> <div id=yiv175248011><!DOCTYPE html PUBLIC
> "-//W3C//DTD HTML 4.01 Transitional//EN">
> <html>
> <head>
>
>   <title></title>
> </head>
>
> Good morning Don,<br>
> FPPF will not remove sediment. Most of the water enters the
> tank
> dissolved in the fuel. Imagine fuel looking like a
> collection of volley
> balls (fuel molecules) with marbles (water molecules0 in
> the space
> between the volley balls. Refineries water wash fuel
> at about 200F as
> one of the last processes before storing the fuel in large
> tanks wiih a
> water layer in the bottom. As the fuel cools the diameter
> of the volley
> balls decreases squeezing our the marbles. The water
> molecules collect
> as free water and settle to the bottom of the tank. In your
> boat tanks
> are filled just before winter storage at lets say 65 F
> ambient
> temperature. Winter arrives, as it looks like it will
> tomorrow, with
> ambient temperatures in the teens and water molecules are
> squeezed out,
> form free water, and settle to the bottom of your tank.
> Biocide will
> help ; however, more water may collect than can be treated
> by the
> chemical. The best way to solve this problem is no free
> water. FPPF
> absorbs free water molecules and is burned by the
> engine. I double the
> dose in the winter to ensure that there is sufficient FPPF
> to remove
> all free water as it is formed. <br>
> <br>
> I am not a diesel engine expert. Assuming the maximum RPM
> shown below
> is underway making way, might check the size an pitch of
> your propeller
> and engine RPM at full throttle withthe transmission in
> neutral before
> messing with your engine. I have blue smoke also during
> warm up. I have
> an 80 HP Yanmar with 6612 hours of operation. The only
> injector
> maintenance needed since tip replacement in 2002 was one
> new tip spring
> 2008

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