At 03:37 PM 12/28/98 -0600, Walter Wise wrote:

Thanks, Walter; that was an excellent site.  I've book marked it for future
reference.  If anyone did not take Walter's suggestion seriously, I'd like
to encourage you to re-consider.  That was by far the best article that I've
ever seen written on the topic.  I do not disagree with any of it.  It is a
very excellent place to start a discussion in this forum.  David Pascoe
addresses bilge pumps for all boats in general very well, but some of what
he says can stand to be either emphasized or added to for application to
trawlers in particular.  I'd like to suggest several things, some of which
could be threads in their own rights.  I'll get them started in the hope
that some of you will jump in and get some good discussion going.

1. WATER TIGHT COMPARTMENTS:  This really does not have anything to do with
   bilge pumps in particular, but I've always considered them to be very
   important.  Doulos will have many, which will run from the keel all the way
   up to the sheer clamps.  I'm curious to know what other folks think of water
   tight compartments, and how you have addressed them in the designs of your
   own boats?  I mention this first only because it relates to several of the
   other items below.  At the very least, you need twice as many bilge pumps as
   you have sealed compartments; since each compartment needs at least two of
   them.  (In the case of Doulos, I only plan to put one pump per compartment.
   This decision is based upon factors that would not apply to most of your
   recreational boats.)

2. BULKHEAD HOLES:  Where you do have water tight compartments, how have
   you handled the holes where you had to pierce the bulkheads for wire and
   plumbing runs?  Doulos' catamaran design renders this concern into a
   non-issue since she will not have any wire or plumbing runs in the hulls,
   but I was wondering how the rest of you have dealt with it.

3. DISCHARGE PLACEMENT:  I understand the desire in a recreational boater's
   mind to keep the discharge as near the waterline as possible.  It is quieter
   that way, and it minimizes hull staining.  Commercial boats are different.
   Many discharge several feet above the water line.  They also have another
   problem, however; in that the waterline varies so much.  On Doulos, the
   waterline is really a range of five or six feet.  At some times and under
   some conditions, my discharge will be below the water line.  The design of
   my system must therefore take this into account.  I bring this up only
   because sometimes your discharge may be below the waterline as well.  This
   could be due to unusual loading of your boat, or it could be that you will
   take on quite a lot of water before you notice it so that you can deal with it.

4. RISER LINE:  It goes without saying that your discharge line will have a
   riser loop in it.  It would pretty much take a moron to overlook something
   that is both as simple and as critical as this.  In normal conditions, it
   will prevent the siphon problem.  In abnormal conditions, in which your
   discharge is below the water line, however; it will not prevent siphoning.
   I'm curious as to how other folks have dealt with this in their design.  I'm
   convinced that we all need something more than a riser to depend upon to
   break the siphon.  I know of several ways of doing this, but I'm curious as
   to what you folks have found that works well?

5. HYDRAULICS:  It is getting to the point at which an engine mounted
   hydraulic pump can serve so many useful purposes, it is difficult for me to
   envision building a trawler without at least one of them.  I like the idea
   of having a high capacity engine driven bilge pump, as suggested by the
   article; but I like the idea of turning it with a hydraulic motor.  This
   makes it very easy to locate the pump any place you like; or even to make it
   portable from one compartment to another.  Doulos will have a high capacity
   hydraulically powered water pump that will be used for several purposes.  It
   will also be plumbed into each compartment, so that it can clear water very
   quickly from any or all of them.  It will be a commercial centrifugal trash
   pump, of the type used by industry for pumping acids and caustic liquids.

6. WIRING CONNECTIONS:  This article makes some very excellent points.
   These have sunk many boats after they have caused bilge pump failures.  I've
   invented a 100 percent sealed connection that is simple and cheap, and have
   used it on a number of boats.  It is very similar to the connections used by
   underground cable companies for repairing buried cables.  You can buy those
   if you like; or you can improvise one of your own very cheaply. The idea is
   to pot the connection in either silicon rubber or in epoxy.  If you use
   silicone rubber, buy one that does not smell like vinegar when curing.
   Those will cause your connections to corrode seriously over time, even if
   they are completely sealed within the potting compound.  Some of the
   commercial boats that I know of run all their wiring inside of sealed
   conduits, and then circulate oil through the conduits.  That is the best
   solution; and possibly another application for a GCF, since they pull the
   moisture out of the oil.  I've been playing around with the idea of making
   this just one more circuit in Doulos' hydraulic system.

7. BATTERIES:  I really like what the article said about the automotive
   batteries.  I'm assuming that none of us put these things into our trawlers.
   I take issue with the author's ideas about using a single large battery in
   place of several smaller ones; however, since I much prefer to have
   batteries that are small and light enough to handle easily.  The modern AGM
   batteries are extremely nice and well suited to recreational trawler service
   -- though they are very expensive when used as storage batteries.  Golf cart
   batteries are a good alternative, for those like me who are very concerned
   about saving money.  Without a doubt, electric forklift batteries would be
   the cat's meow for trawler service; but you would have to have these custom
   built to fit your trawler.  (That is not really a problem.  I have them
   custom built to fit forklifts and other equipment all the time.)

This could go on for quite a while.  My only real intention is to stimulate
further discussion, so I'll quit here.  What do the rest of you have to say
about these things?

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
::
Paul and Cindy Kruse      ::  KJV Joh 14:27 Peace I leave with you,
165 South Kenneth Court    ::  my peace I give unto you:
Merritt Island, FL  32952  ::  not as the world giveth, give I unto you.
E-mail:  plkruse@iu.net    ::  Let not your heart be troubled,
407-453-6206              ::  neither let it be afraid.
::
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Paul Kruse wrote:  in response to Walter Wise's remarks

Arild Jensen comments:

The expensive way is to use gland fitings such as is used  for swimming
pool and other undustrial watertight applications.  These glands are
watertight to some extent and can be made more so by filling with  sealant.
However, this will make subsequent reuse problemantic.  Simply caulkingthe
whole mess with bigs gobs of silicone or other sealant is not recommended.
This si the approach  used by Carver on their big yachts and I can attest
to the lack of sucess from having to deal with the results.

The best  solution  is implemented at the design stage.  The main power
wiring race ways are placed high up along the gunnel and wire drops are
placed into each watertight compartment. where called for.

Plumbing due to being essentioally watertight can be mounted lower down
without adverse ramifications.  Here the plastric gland fittings available
through most jobbers are adequate.

To avoid condensation do not use tubing or conduit for the wire runs..
Instead use the open lattice wire duct. These plastic  ducts come in a
variety of  sizes and shapes., complete with snap on lids.
Many production boats currently use them.

One unfortunate  aspect of  this traditional wiring method is  large
bundles of cables running parallel  for much of the boats lenght going from
the main distrubution panel to the end use device;  be it service light,
bilge pump or whatever. This makes sealing very difficult.  Or else you
sacrifice some watertight height.

European wiring  techniques  offers a solution which will reduce the amount
of wire and deliver clean  power with a minimum of voltage drop between
source and load, while at the same time making it easier to ceal the wire
as it poasses through a watertight bulkhead.

The system is called a ring main.  A large conductor sized to take the full
maximum load is installed in a ring around the perimeter of the boat just
below  main deck level.  The higher the better.
Sub panels are tapped into this main ring at convenient points along the
way.  Each sub panel has a circuit breaker sized to protect the branch
wiring.  The feed point from the power source  ( gen set or batteries)  is
fused at the maximum current capacity of the source or main distribution
ring whichever is the lesser.  From each sub panel normal wiring techniques
can be used.
This design will work for both AC and DC.

So what is the advantage o fthis system.  Cost savings in wire, probably
installation time and material cost certainly is reduced with smaller  wire
sizes needed to deliver adequate power to all points of the boat.

If you choose to  install water tight bulkheads, there is a lot less  work
involves in sealing a couple of conductors passing through  each bulkhead
than sealing a huge bundle  consisting of  perhaps dozens of wires and cables.

I don't know if there is a lot of interest in this topic on the list.
To give you some figures I reduced power wiring costs from  an estimated
$5000 to about $2000 by utilizing this design.  Instead of using  plastic
coated stranded  tinned wire, I designed the main power buss using solid
copper bar stock.  To account for vibration and flexing of the whole
structuer we fabricated PVC holders machined to let the bar stock slide
back and forth but not up and down.  The PVC holders were drilled and
tapped to each vertical steel frame and the copper bar stock was coated
after we had bolted and soldered each joint.  This eliminated short
circuits if anything accidentally dropped  onto the live copper buss bars.
We usd flexible cables from the bar stock to each sub panel.  Standard
circuit breakers  were used throughout.    The  11 kilowatt diesel
generator was fused at 300 amps where it fed the main ring. The main ring
was designed to handle 450 ampos continuous. with only a 3% voltage drop.
This was one of the primary design criteria  and the reason I opted for
such an unconventional choice.  Two years after installation the owner is
still very satisfied with the  design.

Paul's question  made me realize that this design would also be an
advantage when using watertight bulkheads  for the reasons detailed above.

regards

Arild