depth v fishfinder

[cameronke]

I would like to fit some instrumentation namely depth and log. I would prefer not to make any holes in the hull for transducers. I have seen fishfinders with transom mounted transducers so no hole in hull. These units also appear to give an idea of the bottom composition. I could then satisfy my log requirement using a GPS. So the debate is a budget depth/log ( which may require holes in hull for transducers) versus a fishfinder and GPS. I really only want a log for monitoring sail tweaking I would value any comments. Best regards to all

 

[Trevethan]

a number of transom mout fishfinder transducers also supply log option. Check out garmin and humminbird

I am still in the process of looking for one, and like the idea of transom mounting, but have had conflicting info regarding its suitability with an inboard engine... the prop wash messes up the sound waves apparently.

I think I will likely end up replacing the old seafarer with a Nasa unit with a thru hull (the sender on the seafarer is shot) and I have been told the sender units are much the same size so won't have to drill huge holes.

That will give me reliable depth info when under power. And then a transom mounted fishfinder for finding fish and when under sail.

regards,

Nick

She had a deep, throaty, genuine laugh, like the sound a dog makes just before it throws up

 

[Buck]

Try the Echo Pilot unit, better with through hull mounting but no moving parts for log or depth and mounts flush to hull.

Buck

Relax, life is just a game.

 

[JerryHawkins]

Mount inside hull

Most transducers (TXR) irrespective of where they're designed to fit can be mounted inside the hull and will transmit through the hull material.

If you have a balsa-core GRP hull then you'd need to cut away to get to bare GRP. TXR can then either be mounted in a 'blob' of epoxy (stirred slowly with hardener so no air bubbles!!) or mounted in an oil bath - glass a small plastic pipe to hull, fill with castor oil and insert TXR.

I have two like this, an old 'Nasa' style rotating display model and a up-to-date Simrad IS15 depth unit - both work fine. The only thing you lose is some sensitivity and maximum depth is reduced. Look at Lowrance web site (can download manuals) they show the transom mount TXR as being able to be mounted in an 'epoxy blob' inside hull.

Cheers,

Jerry

 

[Trevor_swfyc]

Cameronke, hi try and get hold of a copy of Sailing Today Aug 02. One of the most important points paddle wheels and tranducers must be located in an area of minimum turbulance, invariable this means in front of the keel. Agree with you about holes in the boat but the transducer does not require one mount this with an inboard fixing kit and use castor oil between hull and transducer. I had a trailing log but never used it as I was concerned about reversing over it. So with a new hole cutter and gritted teeth I now have a paddle wheel fitted. Oh my choice was Nasa Clipper they look the part and so far work very well. No doubt you could pay more for a "better" unit but I have no complaints.
All the best to you.
Trevor

 

[Aeolus_IV]

Re: Mount inside hull

It was suggested to me (by a proffesional instrument fitter), that you can install a depth transducer inside the hull using a carefully laid (and large) blob of silicon sealant. Simply push the transducer slowly into the sealant before it sets. Naturally only a temorary arrangement, but allows you to move the transducer about until you get a location you're happy with. Mine has been installed like this for 6 months now and works perfectly - once the boats out of the water I install it properly.

Jeff.

 

[spannerman]

Re: Mount inside hull

Dont know who your 'professional instrument fitter' is but every depth sounder installation guide I have seen specifically warns not to use silicone sealant or similar compounds as they act as a shock absorber and prevent the transducer from sending its sound wave thro' the hull and therefore give inaccurate readings, transducers have to be mounted with a 'hard' compound such as epoxy to get reliable readings.