Through Hull Transducer questions

[jukes23]

Hi,
I am getting ready to install a new raymarine electronics package into my 1987 seafarer. I am going with a B60 through hull transducer. Before I ordered the package, I called up Grady white to confirm the angle of the hull. The woman I spoke with confirmed it was a 20 degree deadrise. I took a measurement with an app for my iphone and it came closer to 25 degrees. My questions are:

1. Is the deadrise 20 degrees or 25? I would tend to think that grady would know better than a phone app, but its at least worth checking into.
2. What is the best placement in the hull to get the best results?

Thanks,

Joe

 

[ocnslr]

I'm pretty sure that the deadrise is 20* and not 25*.

As to placement, you will have to place it somewhere near the stern, as the deadrise changes (i.e. increases) as you move forward. A little bit probably wouldn't hurt, but if you mount it where the deadrise has increased significantly then it will not be pointed down at the bottom, but out to the side to some degree.

It would not be placed aft of anything that will cause disturbed water flow, such as a strake or thru-hull fitting.

Brian

 

[jukes23]

Thanks for the reply.

Should I worry about interference by putting close to a livewell pump? (meaning should I make sure its 1-2 feet away from any pumps)
I was thinking of putting it about 3.5-4 feet from the stern on the starboard side of the keel ( maybe 4-6 inches offset the keel)

Thoughts?

 

[ocnslr]

I have never heard of pump interference with a transducer. Only interference if the transducer is behind or near a scoop injection or other projection from the bottom that causes "dirty water", i.e. aeration.

If your location looks clean, then you can try it there. You can also try it from inside by putting the transducer in a large ziplock bag full of water and placing it where you want. You can see how it reads at rest and then compare that to different speeds at the same depth/location. Have a friend hold it in place if you can't brace it in position.

I've had an Airmar M256 shooting through the hull for ten years, and have used small Lowrance hockey pucks and skimmers as well, in addition to the big Airmar.

Still have the M256, but with P66, TM150M and LSS-2 on the transom.