Hunter Vision 32 - ST50 knot meter?

[rkinross]

I have a 1991 Hunter Vision 32 recently purchased and I am trying to fix some problems discovered after purchase. There is a small leak coming from the knot meter on the port side of the bilge. I think Hunter installed Raymarine ST50 knot meters on this model. Could anyone confirm this? I downloaded the owners manual for the ST50 but it does not say what type of sealing compound to use. Does anyone have any recommendations on how to try to fix this leak? The boat is currently on the hard in winter storage and I would like to fix this as a spring project.

 

[jssailem]

Ok You are correct about the lack of detail. The Item you are installing is a "thru Hull Transducer". There are several made. All have the same basic needs. A clean hole and area around the hole, and a marine sealant. One of the popular manufacturers of such thru hulls is Airmar. Here is the description from their installation guide.

Bedding
CAUTION: Be sure the surfaces to be bedded are clean and dry.

Apply a 2mm (1/16") thick layer of marine sealant around the flange of the housing that contacts the hull and up the sidewall of the housing (Figure 4 or 5). The sealant must extend 6mm (1/4") higher than the combined thickness of the hull, washer, hull nut, and any spacer. This will ensure there is marine sealant in the threads to seal the hull and to hold the hull nut securely in place.​

They use the term Marine Sealant. Since this is a "below water line" install you need to use a sealant that is for under the water use. A popular sealant that meets this criteria is 3M's 5200. There are others but be sure they are rated for UnderWater use.

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[LeslieTroyer]

In addition to what @jssailem said make sure any backing block material has not rotted due to water intrusion.

Les