FCV-585 w/ SS264N on ProKat 2860



I just had an FCV-585 installed on my boat with a SS264N. The installer placed the transducer on the Starboard side of the Port sponson about 3" in from the transom (6" to the middle of the Transducer). Here is the issue, at speeds less than 8 knots I have a great bottom picture. Above 8 knots I start to get gaps in the picture and they continue to get bigger as I go faster. In 2-4' seas I completely lose the bottom and the machine appears to be searching for it and changes ranges from several thousand feet to several hundred. Its only 35' deep btw. Turning the boat to the left while on place makes the gaps go away and turning the boat to the right while off plane but above 8 knots makes it clear up. The opposite direction depending on the speed of the boat.

Please help. :think


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Thanks for posting the pictures of how your ducers are mounted. The performance you are describing (gaps in the bottom) is a chassic sign that bubbles are passing over the face of the transducers. Depending on the shape of the hull and the speed of the vessel, bubbles flow back and outboard. Flush mounted transducers are more suspectable to bubbles than transducer mounted in fairing blocks.


Hi Repmuj,

Perhaps the transducer is mounted too far back.
Most likely installed forward on your boat has less turbulence.

What is in this picture ?



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Snips, Thanks for the response. I believe the problem is the reverse chine on the inside of the sponson. I think it is channelling bubbles back along the hull and over the transducer face. I took the boat out again for another test and at 6.5 knots I was hitting some chop caused by a strong wind in the river. I started getting gaps in the bottom machine. With each wave I hit I got a short gap. The bubbles caused as the boat hit the wave were traveling back along the hull. At this point I dont think I can install the transducer anywhere that wont be susecptable to the bubbles and not be sitting on the bunk while on the trailer. Have you heard of any other Cat owners having good luck with the M260? One person responsded to my comments on thehulltruth.com and has a 26' version of my boat and has installed the M260 directly of the keel of the sponson and says he is holding bottom. I would like to have more confirmation before making another mistake. This one isnt going to be cheap. I am going to have to have the SS254N removed and since its used the company will not exchange it. I dont suppose you know anybody that needs one and where I can get a deal on a M260? Its worth a try.

Narvalo - That is just a shiny spot on the hull from us getting under to take pictures. I double checked after seeing your post.
I went online to get a better idea of your hull design. While those Cat hulls are a more comfortable ride they can be a bear for transducer mounting. You may (or may not) have better luck with the M-260 but if you are thinking about going that direction there are two things to consider. First is the loss of sensitivity because of the thickness of the hull you are sending/receiving through and the second is finding an area that is bubble free. Most of the vessels I saw online had transom ducers probably for this reason. While I am not a fan of transom ducers I would probably lean that direction rather than the in-hull M260 in this case. One option may be the 525TID-TMD.

I run a 27 tournment Worldcat.I have run a B260 transducer with a high speed faring for over 10 years know.A big thru-hull will work on a cat.I had a company cut the block on a large band saw first,then we kept sanding the plastic with various sanders and grinders.We kept dry fitting until it was perfect.My transducer with the faring is HUGE 21" long and hangs down 4 plus inches.Worldcat told me where to mount it.It is on the same side as yours all the way back like yours,but my hull is much differnt.I had one mechanic tell me it would over heat the motor on that side,because he said it took away water from the motor.I ran the same motors for 8 years(Honda) when one went it was the other motor.3000 plus hours.I have replaced both now.There are alot of things to consider when going to a thru-hull.I keep my boat on a lift-it has to sit on there just right,not to touch the transducer.You alaways know it is hanging below your hull.You just don't go on a flat to throw the net.You have to be carefull in skinny water.More than likely you will have to modify your trailer.I have had my boat on a trailer before.I do not own a trailer.Yes a thru hull is alot of work and labor to fit right,but if you have it done right you will LOVE the preformance.Thru-hull's are the best. GOOD LUCK,Capt.Mike www.daybreakercharterfishing.com

I have an M260 in my Grady mono-hull and it works fine. I think you will be happy with the M260 if you find the proper location inside the hull and since the M260 is fairly easy to move, you should be able to find the sweet spot. Regarding your SS254N, it might make a better plug for the hole in the hull than fetch a few dollars for a used x'dcr. You might want to add a switch and use both for differing conditions.