knot meter question and leaky seacock question

[Linda]

Hi, My cd26 got hauled out today and I've noticed that the little impeller wheel (if that's what it is called) which spins and tells your knot meter how fast you're going has gotten very hard to spin. The unit was made by Datamarine. Is this something that just need to be cleaned, or replaced? I heard Datamarine was out of business. Any help would be greated appreciated. thanks, PS I had the boat yard clean and grease the sea cock that drains the sink this spring. It was leaking from the barrel. Alas, it still leaks... Do I need to replace it or clean it better?? Thanks, Linda



CD26LA@aol.com

[Greg Kozlowski]

Linda,

Datamarine seems to be alive and well, though some parts for their
instruments may no longer be available. They serviced the Corinthian Series instruments on my Cd 36 just this summer. Here's e-mail contact info:

Datamarine Service related questions (Datamarine Products only).
dmifix@capecod.net

Good luck,
Greg





koz@seijo.ac.jp

[John]

Hi, My cd26 got hauled out today and I've noticed that the little impeller wheel (if that's what it is called) which spins and tells your knot meter how fast you're going has gotten very hard to spin. The unit was made by Datamarine. Is this something that just need to be cleaned, or replaced? I heard Datamarine was out of business. Any help would be greated appreciated. thanks, PS I had the boat yard clean and grease the sea cock that drains the sink this spring. It was leaking from the barrel. Alas, it still leaks... Do I need to replace it or clean it better?? Thanks, Linda

I believe Datamarine was bought out or merged with SEA and became Datamarine International (DMI for short). Here is the contact info I have for them:
Datamarine ( or SEA )
7030 220th S.W.
Mountlake Terrace, Wa. 98043

PH: 425/771-2182
FAX: 425/771-2650
WEB: www.sea-dmi.com

As for the seacock I assume you are describing a problem with the original Spartan seacock that came from the factory. One of a few different reasons could be the cause. First, it may have been inadequately greased on the barrel and inside the body. Two, it may have been improperly adjusted. Three, the barrel may not have been adequately lapped to seat properly with the body. It may be caused by any combination of the previous points. Also check to be sure no electrolysis damage is obvious on the barrel or inside the seacock body. Apparently the yard did not perform the service correctly. I would think it should be a redo at no $$$ to you if it's been leaking since last spring and they were notified of the problem when it first started. You'll probably have to fork over more $$$. Take it to a professional yard with qualified people. It's not a difficult process to do properly.

The impeller problem could just require lubricating ( use a lubricant impervious to salt water ). The small axle the impeller rides on could be bent. Usually they just need a good cleaning and lubrication. When you put antifouling paint on the impeller be sure not to get it on the axle.

[Russell]

The engine intake seacock on our CD 36 had gotten to the point where it the handle would turn loosely and it would leak, even after the adjustment ring was fully tightened, ie, when the barrel was flush against the adjustment ring. I fixed this by cutting a gasket that held the adjustment ring a bit further from the housing, thus creating an "even tighter" position that had not existed before. I suspect at some point I will have to replace it.

[matt Cawthorne]

Linda,
Use the search feature to review posts on lapping seacocks. The job is not difficult. If you have the spartan drum type you can buy the lapping compound (and the thin 15/16 wrench if you do not have one) and get them to send instructions with it.
Matt

Hi, My cd26 got hauled out today and I've noticed that the little impeller wheel (if that's what it is called) which spins and tells your knot meter how fast you're going has gotten very hard to spin. The unit was made by Datamarine. Is this something that just need to be cleaned, or replaced? I heard Datamarine was out of business. Any help would be greated appreciated. thanks, PS I had the boat yard clean and grease the sea cock that drains the sink this spring. It was leaking from the barrel. Alas, it still leaks... Do I need to replace it or clean it better?? Thanks, Linda

mcawthor@bellatlantic.net

[Russell]

You can buy lapping compound and a better 15/16" wrench at any hardware or auto parts store, for a fraction of the price you get them from Spartan. The process itself is easy. Clean the parts. Put the compound on the barrel. Insert loosely into housing. Rotate a few dozen times until the surface of the barrel smooth(er). Clean off the compound. Grease the barrel and put everything back in place. Adjust.

I like Spartan hardware, and may buy some toerail cleats from them in the future, but I see no reason to pay a lot for a cheap wrench.

[Evan Kramer]

I have a Datamarine knot meter on my CD 28, and I have found that I need to clean the wheel every
two months or so to keep the thing working properly. I just pull it out (inserting a plug, of course),
clean it up and put it back. The process allows a couple of gallons of water in the space surrounding
the seacock, which is easily cleaned up, but I haven't found and can't imagine any other to clean the
thing. Good luck.



evankramer@hypercon.com

[Matt Cawthorne]

True the price of that wrench is high, but the cost of running around trying to find a 15/16 wrench that is thin enough can be high as well.

In addition, To properly lap a seacock you should do 10, 90 degree oscillations, then turn 1/4 turn and do 10 more 90 degree oscillations etc. until lapped bands show up continuously around the ends of the barrel. You then need to get ALL of the grit off of the barrel and out of the housing. Only when the two parts are absolutely clean should you grease them and re-assemble. Why the 90 degree oscillations? I do not know, but I have heard the recommendations from a couple of sources.
Make certain when re-assembling that the washer that acts as a stop is properly seated. Do not over tighten. You should be able to work the seacock without much effort. The only one that should be a little stiff is the engine seacock. You do not want that one vibrating shut.

Doing the seacocks is one of my least favorite jobs, but re-lapping should not need doing very often.

Matt

You can buy lapping compound and a better 15/16" wrench at any hardware or auto parts store, for a fraction of the price you get them from Spartan. The process itself is easy. Clean the parts. Put the compound on the barrel. Insert loosely into housing. Rotate a few dozen times until the surface of the barrel smooth(er). Clean off the compound. Grease the barrel and put everything back in place. Adjust.

I like Spartan hardware, and may buy some toerail cleats from them in the future, but I see no reason to pay a lot for a cheap wrench.

mcawthor@bellatlantic.net