Shoot-Through-Hull Transducer

[mrmamiller]

I am planning on installing a shoot-thru-hull transducer on my boat, 2003 Century 1700CC boat, 15 degree deadrise, assume no coring in the fiberglass. I already have a transom mounted transducer going to a different sounder, and am adding a new sounder, one that will be better at picking up readings in very shallow water. There are thru hull fittings on both the port and starboard for water pickup and drains. I will make a test using old bag of water, but I have a few questions first.

1) Can I mount the transducer directly over the keel without hurting the performance (as opposed to off to the side of the keel)? I was wondering if the glass might be a lot thicker over the keel and also wonder about the multiple angled surfaces being worse for signal receive.

2) I plan to pick a spot forward (upstream) of the pickup/drain and am wondering if there is a certain distance forward of the thru hull fittings that the transducer needs to be?

3) Is there a preferred epoxy to use for mounting the transducer? I know that it shouldn't contain air bubbles and the slow cure epoxies are better for this. I have seen lots of recommendations and and all of the reasons why you shouldn't use most of those recommended products. I don't want to use an Airmar P79 at this point, nor do I wish to mount a tub with mineral oil or antifreeze. Would the "clear" epoxies be better than the opaque ones?

Thanks for your help and advice, Mark

 

[dingbat]

Re: Shoot-Through-Hull Transducer

1. Thicker absorbs more signal. Thickness (as a percentage of wave length, not thickness ) has an effect on sensitivity.
Keel puts you dead center in the middle of the prop wash in reverse. Not good if you use reverse thrust to hold position a lot.

2. 12-18" is recommended

3. The 15 degree deadrise is not doing you any good, especially in shallow water. Highly recommend addressing the issue.

Color of epoxy is irrevlent.

Good shallow water performance is a function of ping rate and the "Q" value of the transducer. One without the other is futile.....

 

[mrmamiller]

Re: Shoot-Through-Hull Transducer

Well, if the xducer can't be over the keel and it has to be more than 12" ahead of a thru hull fitting, I guess I am back to measuring shallow depth with my piece of pvc pipe with inch/foot markings. Thanks.