On Thu, 23 Apr 2015 07:14:36 -0400, "Flying Pig"
wrote:

Hi, Bruce,

Yes, but :-)

From your description you seem to have an "all dancing, all singing",
nav system. Doesn't your GPS positioning system tell you all that?

No. Or if it does, I've not discovered that secret yet. I use it like dead
reckoning - estimates in my head. I get heading and COG and SOG, but
nothing fancier than that and the wind which shows analog apparent and
numeric velocity - no calculation for true wind, either.


But, isn't COG/SOG the critical information? I remember going up the
Malacca Channel one trip with a very inefficient propeller doing,
according to the impeller operated speed log, about 4 K... Against a 3
K current. I've also been traveling the other way with the speed log
indicating 3 K. In nether case did the speed log give a very accurate
picture of when we would get to Port Dickson :-)


A car water pump is a centrifugal pump :-)

I suspected as much


What I used is similar to
http://www.acepumps.com/en/index.php...ducts/C6/Belt/
gives an indication of the installation.

But, it is not a simple "bolt on" modification as it requires a spare
sheave on a drive pulley somewhere and a mount which is attached to
the engine, and might well not "fit" some installations.

Interesting. It would take some doing to match it up to, and enable
tightening, our pulley. As it happens, I have a PTO stub and a 3-sheave
pulley, removed during the refrigeration change (they had one of the old
Tecumseh pumps and AC split cold plates system)...

Are they rebuildable?

In a sense. If the bearings required changing then yes. But if the
impeller were to be damaged then "yes but perhaps cheaper to change
the pump".

Another point is that a centrifugal pump is not self priming so the
pump must be below the source water level. However, for long term
service is certainly was more effective than the rubber impeller type
although the rubber impeller pump is self priming.

No problem on our boat; the mounting point would be below the outlet, let
alone the top, where the water line is, of our filter housing.

As long as there is positive water pressure to fill the pump with
water the pump will "prime" and once it starts pumping will continue
to do so - with some limits of course.

A solution I've seen that works with apparent success and completely
eliminates the raw water pump is the use of a keel cooler which, if I
were building a new boat I believe that I would look at very closely.


One of the owners of the company I worked for in Indonesia bought a
Grand Banks and had so many raw water pump failures on the twin
Caterpillar engines that he bought two spares and kept them in the
engine room ready to bolt on when (not if) one failed.


I've seen them used on fishing boats where the "cooler" was simply a
"loop" of galvanized iron pile extending along the bottom of the boat.
see: http://tinyurl.com/o8vkcuh

I don't think I'd want all that hanging under my boat, making cleaning even
more of a chore than it is now!

That was an explanation of how simple a keel cooler could be. A more
luxurious example would be like something shown at
http://tinyurl.com/nmyh6sd

The advantages are, of course, no seawater inside the boat and one big
disadvantage is no exhaust water to cool the exhaust :-(

Cheers back atcha

L8R

Skip

Morgan 461 #2
SV Flying Pig KI4MPC
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--
Cheers,

Bruce