Shoot thru hull sonar or Transom mount sonar ?

Replies to This Discussion

Permalink Reply by Eric DeLay on July 24, 2009 at 5:07pm

If you already have a shoot-thru transducer then why are you installing a transom mount unit? Are you not happy with the performance of the one you have? I did mount one on the outside of my first boat and unfortunately you have to drill some holes in the hull to mount it. My second boat had the shoot-thru type and it seemed to work fine. You may get less interference from the transom unit but I doubt it is a significant difference

I now have a Humminbird Side-Finder so it is mandatory to have it on the outside.

Permalink Reply by Rick Crawford on July 24, 2009 at 5:22pm

part of it is my newer unit will not match up with the current transducer. But i was also wondering about the interference as well thanks.
Eric DeLay said:

If you already have a shoot-thru transducer then why are you installing a transom mount unit? Are you not happy with the performance of the one you have? I did mount one on the outside of my first boat and unfortunately you have to drill some holes in the hull to mount it. My second boat had the shoot-thru type and it seemed to work fine. You may get less interference from the transom unit but I doubt it is a significant difference

I now have a Humminbird Side-Finder so it is mandatory to have it on the outside.

Permalink Reply by Eric DeLay on July 24, 2009 at 5:26pm

Hopefully Marc, or Ron, or Tag, or someone with more experience in this area will weigh in.

Permalink Reply by Daniel on July 24, 2009 at 7:13pm

I would just do a shoot-thur again. All you have to do is take your old one off the pad and clean the area to install the new one. Its very easy and half the work is already done. the wire path is already done and you dont have to mount anything on your transom or jackplate.

Permalink Reply by Marc Marcantonio on July 24, 2009 at 7:52pm

What unit are your mounting? In 90% of the cases I would recommend shooting through the hull. Most modern units have more than enough power that you will not notice a difference in sensitivity.

In fact, you usually experience less interference since a proper through hull mounting puts the face of the transducer where you have laminar flow (clean water flow over the face of the transducer without air bubbles that cause interference).

No worries about knocking the transducer out of alignment, or breaking it from hitting logs, etc. You also get less chance for damage to the wires since they will be protected in the hull. The installation will be clean, and as Eric mentioned, no hulls in the transom which can come back to haunt you.

ciao,
Marc

Permalink Reply by Larry Austin on July 27, 2009 at 11:56am

_I'd go shoot thru if you can. My latest fishfinder had a transom mount transducer that I installed (old was shoot thru...never a problem) and I've already knocked it off, Lk Samm. (didn't even know it, but must have brushed a dock or piling) after re-installing it due to interferance. I've just odered a shoot thru and their easy to install. Now I've got plugged holes in my transom that I'm not happy with.

Permalink Reply by Steve Hastings on July 27, 2009 at 2:32pm

I'd also suggest shoot through. Learned from Jeff Boyer, ( Lowrance Pro Staffer) what Marc mentions about clean water movement after I had drilled holes and mounted it in the only area I could, that happend to be on a spot where an angular part of the hull met the transom. Never got over 22mph with it working. (Lowrance LMS337C) . By mounting inside you can find a level spot on the bottom and put it there. Don't epoxy it down till you test it all speeds. Do it on the water.......... Dry fit with modeling clay around it, then a slow drying epoxy, is the answer to the next question.

Steve

Permalink Reply by Rick Crawford on July 29, 2009 at 6:43pm

thanks guys


Steve Hastings said:

I'd also suggest shoot through. Learned from Jeff Boyer, ( Lowrance Pro Staffer) what Marc mentions about clean water movement after I had drilled holes and mounted it in the only area I could, that happend to be on a spot where an angular part of the hull met the transom. Never got over 22mph with it working. (Lowrance LMS337C) . By mounting inside you can find a level spot on the bottom and put it there. Don't epoxy it down till you test it all speeds. Do it on the water.......... Dry fit with modeling clay around it, then a slow drying epoxy, is the answer to the next question.

Steve

Permalink Reply by Stroller4Life on July 30, 2009 at 7:15pm

Just as the other guys have stated, on a modern bass boat, shoot through is definitely your best option. Save for a specialty application like side scan that is. The best way to remove your old transducer is to place a block of wood next to it and hit the block with a hammer. This keeps you from damaging the old transducer should you need it for anything in the future. Just be sure to get the new transducer as level as possible when you install it.

On a side note, transducer interference is sometimes unavoidable regardless of where your mounts lie. Bear in mind that the diameter of a 200 kHz transducer's cone is roughly 1/3 the depth of the water you are fishing. If you are running two units in your boat at the same time, once you reach certain depths the cones will intersect and cause inaccurate readings. Other factors (clarity, electrical connections, etc.) contribute as well. Adjusting the ping rates will alleviate the problem a bit, but turning one unit off is sometimes your only option.