Where to mount my transducer

j.fishwick · 10 February 2015, 19:38

I am hoping that someone will be able to advise me as to where the best place to mount my transom mounted transducer is, I know on the transom?

I have a Ribcraft 6.8m with twin Suzuki outboards and I was thinking that the best place was just to the port side of the keel. I have attached a picture to this post as it might help to visualise the locations.

Phil M · 10 February 2015, 20:13

Garmin say "On twin-drive boats, mount the transducer between the drives, if possible." and as close to the centreline as possible. On that instruction, I'd go bang in the middle unless it will get destroyed by your trailer.

Phil M

j.fishwick · 10 February 2015, 20:28

Thanks for your reply Phil. I should probably have mentioned that she is normally kept on a drive on versa dock so I was thinking just off the centre line. As my outboards are only 90Hp they are not counter rotating so if I move to the port side of the centre line then the port engine will be on the down stroke, which is what is recommended.

It was suggested to me that I should mount on the starboard side of the starboard engine but I think it will be difficult to get the transducer into turbulence free water and possibly a bit close to water surface.

jyasaki · 12 February 2015, 18:20

Quote:

Originally Posted by j.fishwick

It was suggested to me that I should mount on the starboard side of the starboard engine but I think it will be difficult to get the transducer into turbulence free water and possibly a bit close to water surface.

Not sure what you mean by close to the water surface. The water surface, at speed, will be at the level of the hull.

jky

AJ. · 12 February 2015, 19:51

Why don't you put it in the transom well glue it down with a thick layer of silicone make sure to mix it to get rid of any air bubbles. That's where mine is and works perfectly at any speed and you don't have to worry about knocking it or it flipping up at speed

Sent from my iPhone using RIB Net

9D280 · 12 February 2015, 19:51

If you mount the transducer on a bit of 2x1 or metric equivalent

then use a G clamp on the othrr end to park it in the different locations by clamping it to the transom. When you find the best, fit it properly.

j.fishwick · 12 February 2015, 20:31

Jky,

My understanding, and I could be wrong, is that when the rib gets on the plane and is travelling at speed then the hull will lift in the water so the higher on the V (further away from the centre line) you place the transducer then it could potentially lift out of the water altogether or be in the turbulent aerated surface water. Therefore the closer you go towards the keel then the more assurance you have that the transducer is in 'clean' water passing down the hull, especially during any turns.

j.fishwick · 12 February 2015, 20:38

AJ.
My previous transducer was glued into the base of the bilge, just in front of the transom, but we never had that much success with it. We lost the signal a higher end speeds and had always been suspicious of it's accuracy. This could be due, in part, to it not being glued as you describe and that it was an inferior transducer. Also it always seemed to get stood on by people when sorting ropes at the stern. As my vessel is used for scientific research and up shallow tributaries then precise depth is desirable so for these reasons I have decided to transom mount my new transducer.

j.fishwick · 12 February 2015, 20:39

9D280,

Thank you for your suggestion, I may give it a go and see how I get on.

jyasaki · 14 February 2015, 17:37

Quote:

Originally Posted by j.fishwick

Jky,

My understanding, and I could be wrong, is that when the rib gets on the plane and is travelling at speed then the hull will lift in the water so the higher on the V (further away from the centre line) you place the transducer then it could potentially lift out of the water altogether or be in the turbulent aerated surface water. Therefore the closer you go towards the keel then the more assurance you have that the transducer is in 'clean' water passing down the hull, especially during any turns.

True, to an extent. The hull shape, however, is the "surface" of the water at speed, from the keel to wherever the boat waterline rides while on plane. To put that another way, the "surface at the back of boat while running is the keel at midline, and several inches higher as you move towards the gunwales. The only way you'll lift the transducer out of the water is to mount it a few inches over from the waterline at speed.

The clean water part has more to do with other things than strictly depth: What's on the hull further forward (chines, other transducers, thru-hulls, and the like) and what interference you get from other things nearby (other in-water sensors, spinning props, etc.)

jky

j.fishwick · 14 February 2015, 19:40

Jky

Thank you for your explanation and sorry if my initial posting was misleading. As i have twin engines i was concerned that if i mounted the transducer on the starboard side of the starboard engine it would possibly lift above the waterline at speed, or very close to it. I have now decided to mount the transducer between the engines, mainly for the reasons you have highlighted.

Kind regards
James