F-Ribs And Sibs - Inflatable Boat Community

I have a Elling KB350 and using a Lowrance Hook2 5 Splitshot Transducer.

I have my transducer fitted on the transom as seen in the photo.
My question is
At what speed is it that the transducer stops sending Sonar & Downscan images and how low in the water should the transducer be.

If it’s sitting in clean water then...any speed.

Hard enough on a rigid hull to get consistent readings at planing speeds and not mounted so deep to generate a rooster tail. On a cat hull then even more difficult.

Yours is mounted on correct side of hull to limit prop turbulence so just keep going deeper in small increments until you don’t loose bottom. If this generates excessive splash then you may need to compromise readings with speed.

Thanks for tha advice Ian,
When I had it lower I had a lot of water turbulance with the water working up the outboard and splashing over the transom, at the hight it is at the moment over 10mph I still get splashing over the transon not so much but the faster I go the more this happens, when I take the transducer arm off I do not have a problem.

How can I solve this problem and why is this happenig

Really difficult with a cat as you don’t have the clean water flow off the transom.

Only advice is just keep lifting it higher until the splashing stops and hopefully before you lose bottom.

Worst case scenario is you’ll only get consistent readings at slower displacement speeds.

Some people strap the transducer under the tube at the stern with good effect...might be a solution on a cat.

Admittedly not much relevance to your scenario but this is where our transducer sits. No excessive splashing and still holds bottom at 36 knots....took a bit of fettling though.

harrison wrote: ↑

09 Aug 2020, 20:30

Really difficult with a cat as you don’t have the clean water flow off the transom.

Only advice is just keep lifting it higher until the splashing stops and hopefully before you lose bottom.

Worst case scenario is you’ll only get consistent readings at slower displacement speeds.

Some people strap the transducer under the tube at the stern with good effect...might be a solution on a cat.

Admittedly not much relevance to your scenario but this is where our transducer sits. No excessive splashing and still holds bottom at 36 knots....took a bit of fettling though.


17F89D3A-2EEE-4A7D-8F48-10BE5E59A461.jpeg

I have been out on the river quite a few times now with my kb350 and now the outboard is run in it is going really well, it gets on the plan and settles down easy where I am getting around 19mph from my 9.8hp 4 stroke.

I have found being a cat boat having the transducer mounted on the transom as you would normally do, when I reached over 10mph I had a great disturbance of water that was coming over the transom on the side the transducer was mounted, the faster I went the more water came over the transom, also with the force of water coming out heavier side of the keel tube as you would expect being a cat I loose sonar & down scan at 5mph and going fuzzy as I reached 10mph with the force of the water hitting against the transducer.

With advice from Harrison
I was out in the boat today and held the transducer over the side of the tube the results were much better not having the force and turbulence of water coming from the back, will be buying another borika mount to put on the back of the tube to mount the transducer.