Depth transducers

[Storyline]

Suffering with a failing depth display in the cockpit I am now considering fitting a fish finder as a backup. Not sure which one, would love the new Raymarine ultra hi res one but might go for a cheapy.

Am loathe to make another hole in the hull so I was wondering if anyone has had any success with two different transducer types;

Firstly the type you bond to the inside of the hull (we are an old fashioned heavy thick polyester layup)
and
Secondly, transom mounted ones, we have a nearly sheer stern but only a very small V shaped section is actually in the water and as this is central it is subject to quite a bit of turbulence/prop wash when we are motoring.

Anyone ?

 

[pmagowan]

The transom mounted ones will not work if you are going any speed and getting turbulance. You can get combined sensors for going through your current through-hulls. Mine does depth, fishfind, speed through water and temperature.

 

[Spi D]

Have and have had numerous inside hull transducer with good results (currently with NASA digital and Lowrance HDS10 displays).

Sensitivity logically would be affected, but I get nice readings on both fishfinder and digital sounder.

 

[alahol2]

My fishfinder transducer looks like it is a transom mount but is fitted inside on a bed of CT1. It is right on the centreline ahead of the keel so the layup is likely to be very thick there. It reads perfectly well in all depths that I am concerned with, certainly 30 metres and beyond.

 

[agurney]

My fishfinder transducer looks like it is a transom mount but is fitted inside on a bed of CT1. It is right on the centreline ahead of the keel so the layup is likely to be very thick there. It reads perfectly well in all depths that I am concerned with, certainly 30 metres and beyond.

+1
mine is bedded in a dollop of silicone sealant; works fine to 200' through thick GRP. Needs redone about every five years. You can test where it will work best by putting it in a bag of water.

 

[sailaboutvic]

i dont know what type of transducer you will have with a fish finder , but in the old days we use to fit a plastic tube inside the hull with a sealer , the tube was filled with some oil and the Transducer use to go into the tube , it works well . you had to top it up now and then , no big deal

www.bluewatersailorcroatia.webs.com

 

[Trop Cher]

Like others I've fitted a transducer from a fishfinder inside the hull with good effect on a previous boat.
I've also operated this season without a working depth sounder, and have been thinking of fitting a fishfinder, but also thought of this forward looking depth sounder http://www.echopilot.com/fls_bronze.htm

 

[knuterikt]

Stay away from the transom mounted one, you will get to much disturbance.
Inside mounted works well om most boats, often it is the same type used for through hull installation.
It's easy to test for the a working / best location.
Put the transducer in a plastic bag with water and place inside the bottom of the boat (There must be no air between the transducer and hull).
Some use Plasticine for temporary install (never tried it)

 

[JumbleDuck]

A friend of mine has a 24' Cheverton motorboat with a Garmin transducer mounted on the transom, centrally and therefore about 2' behind the propeller and immediately above its wash. To my surprise it works absolutely fine.

 

[David2452]

I don't know why people think transom mount fish finder transducers would be a problem, if you think the turbulence on a yacht is an issue you should see the turbulence on most of the boats they are fitted to with good effect, high speed sport fishers and high speed trailer boats where they are the weapon of choice, they do need siting correctly though.

 

[knuterikt]

I don't know why people think transom mount fish finder transducers would be a problem, if you think the turbulence on a yacht is an issue you should see the turbulence on most of the boats they are fitted to with good effect, high speed sport fishers and high speed trailer boats where they are the weapon of choice, they do need siting correctly though.

On (many) sailboats the edge of the transom often get out of the water and into the air when the boat is pitching. A MOBO going forward will not be affected in the same way as it drags it's ass into the water.
The depth finder is inaccurate when the transducer is in the air

 

[David2452]

On (many) sailboats the edge of the transom often get out of the water and into the air when the boat is pitching. A MOBO going forward will not be affected in the same way as it drags it's ass into the water.
The depth finder is inaccurate when the transducer is in the air

Quite the reverse, the stern lifts rather than drags when they get going, one of the reasons the transducers are often called "skimmers" I see what you mean about the pitching though.

 

[knuterikt]

Quite the reverse, the stern lifts rather than drags when they get going, one of the reasons the transducers are often called "skimmers" I see what you mean about the pitching though.

I was thinking of vessels moving at hull speed or less since the OP seemed to have a sailboat.
On a planing hull it's different but then the transducer skims on top of hard water.
I have no experience with transom mount transducers on planing boats - how do they perform when running at planing speed in waves?

I know that my transducer can give erratic readings some times when sailing in larger choppy waves, even if it's installed aft of my fin keel..