Location of speed/depth transducers

[Rick]

I'm planning to install speed and depth instrumentation on my '74 O'Day 22 soon and don't want to poke holes in the bottom for thru-hull transducers. The question I have is "where is the best location for transom-mounted transducers?" I have a swing-down swim ladder on the port side and a 6-horse, long-shaft outboard on a lift&lower bracket on the starboard side. My choice would be under the outboard and out of harms way of clumsy climbers....but....I generally sail with the outboard in the water (just too lazy and don't care about the drag) and I notice a lot of turbulence between the transom and the outbaord. Will this turbulence affect speed measurement or will there be sufficient streamline flow coming off the botom? Anyone have any experience with this?

 

[Ben Allen]

Transducer Location

Rick,Mounting your transducer where there will be a lot of turbulance will give you inaccurate readings, although that would be better than not having one at all. Another option would be to mount it forward of the keel in the V-berth, but without drilling any holes. Take a piece of 4" pvc and angle the end to match the angle of the floor in the berth. Mount the pvc so that it is as vertical as possible, next, pour an epoxy bed in the pvc only thick enough to make a flat mounting base so the puck will read straight down. Place the puck inside the pvc, fill with water or mineral oil, rig a cap that allows the cable to exit, and seal the top of the pvc. This way you have a transducer forward of any turbulance, and you didn't drill any holes in your boat.Ben AllenMontgomery, AL"Latte Dah"O 26

 

[Ben Allen]

Privious post would work only on depth, not speed.

For speed, how about a GPS.

 

[Justin - O'day Owners' Web]

I like Ben's ideas

I was going to recommend mounting the depth xducer just as Ben tells you. Be extremely smooth pouring the oil and placing the ducer to avoid bubbles that will cause inaccurate readings.The GPS is wise as well, especially since you can get a decent handheld for less than the cost of a decent knotlog. I wouldn't go with the transom mounts. Turbulance will be a problem, and heeling may pull them out of the water.Justin - O'day Owners' Web