Depth and fishfinders

[Trevethan]

Looking to replace the clapped spinning disc type echosounder as teh trasducer has failed.

I'd like to avoid a lift out so have been thinking about either a Garmin 100 or Humminbird fishfinder. I don't really need to find the fish, but I like the idea of seeing the profile of the seabed before anchoring and they only cost £100 or so.
Two questions really.

The first is will the finder work while using the inboard? I have my doubts the sonar will work well through the prop wash.

Second, I don't fancy making holes below the waterline (the boat is ferro btw) to mount the thing. Wondering if the bracket mounts above waterline and extends below?

All help/advice, as usual gratefully received.

Regards,

Nick

 

[ccscott49]

I would be interested in this aswell, but I don't mind through hull, if it will fit where my old transducer (seafarer) was fitted, is this possible? If so with which fishfinder?

 

[Trevethan]

I don't mind using the old Seafarer hole either, but if I can avoid a lift out then so much the better but.....

Also transom mounted depth log and temp sensor is included in Garmin 100 kit for about £130

Through hull transducers cost a whole lot more up to £280 just for tansducer.. plus head unit.

 

[ccscott49]

I wonder why they cost so much more?

 

[Trevethan]

I think cos they made of bronze rather than plastic. Mind you even a plastic depth only thru-hull was cheaper than the transon mounted three way transducer.

 

[ccscott49]

The seafarer one, has no through hull thing, it just went in a hole, with a nut on it, you had to feed all the wire through first, is this one a bronze through hull, then you put the transducer in that, if so I would need a much bigger hole than before, I'm not up for that, just get a new transducer, for my old one!

 

[Sammy]

Have a look at the Eagle or Hummingbird range of fish finders I replaced my old sounder for the cheapest in the range and have found it exellent. It is possible to use the same sounder as your existing one sometimes, as most of the frequences are the same if not mount it inside and read through the hull.

www.BoatsThames.com

 

[Trevethan]

Thanks Sammy. I looked at the Humminbird line and they along with the Garmin are the two contenders.

Unfortunately its the transducer that's gone om Gayle Louise so plugging in a new head unit isn't going to work.

Also the sounders can only be mounted inside GRP hulls, not wood steel or ferro, as far as I know, so I have to make use of an external transducer.

Regards,

Nick

 

[Guest]

Re: Trevethan

I bought a Garmin 160 fishfinder last year to fit to my twin screw inboard motor cruiser. Discovered that the
transome mounted transducer is no good for inboard cos of the wash.

Fortunately had the boat out for antifoul at the time, so bought a through hull transducer, naturally had to
drill hole through hull to fit it.Works fine and I now use the Garmin all the time although I still have the two spinning Seafarer gauges also.

"The Med is calling me"

 

[ccscott49]

Re: Trevethan

Does the transducer, look like the seafarer type? IE: just a hole in the hull, as opposed to a through hull fitting?

 

[Trevethan]

Re: Trevethan

I c an see twin screws causing all sorts of problems... unless your transom is really wide there is nowhere free of the prop wash. Wonder if the same holds true of single screw boats?

I guess I am just gonna have to call Garmin.

Thanks for the post!

 

[Gunfleet]

I'm not sure that's true. It's the number of voids in the wood that cause the trouble. I had an old wooden Kestrel (mahogony plank) and the man at NASA said to try it inboard, chewing gummed to the hull. Then, once you find it works, you can replace the gum with epoxy. It worked fine. Why not try? Chewing gum is cheap, and you can have the pleasure of making all your kids chew at once in your cockpit.

 

[brianrunyard]

Most of the "Spinning Disk" (Rotating Neon/LED) echo sounders I've come across run at 150KHz, whereas most fishfinders run at 200KHz or 50KHz for deep water, so the transducers are not compatible.

Brian
http://homepage.ntlworld.com/brunyard

 

[ccscott49]

Re: Trevethan

when you find out tell me!

 

[ccscott49]

Re: Trevethan

when you find out tell me!

 

[Trevethan]

Re: Trevethan

The man from Garmin.. he say no.

I'll need a through hull transducer. Price will depend on the angle and thickness of the hull. No way to shoot through apparently.

The Seafarer hole is about 1/2 inch in diameter.Garmin's transducers are 1" or 2" depending on what you go for.

Speed only tranducers cost between about £50 and £150.

Maybe I not bother and try and get a diver to replace the seafarer transducer with a new Nasa one. I think they are about the same size. Any views from those with wetsuits regarding how feasible this is?

 

[ccscott49]

Re: Trevethan

Oh! Bollocks. Well it looks like I'll just replace mine aswell, the NASA ones are identical. Diver, not really an option, trying to feed all the wire through with water pissing in, isn't an option for me, I dive but it's not really the way to go, I'll wait until winter, when I'll antifoul anyway!

 

[Trevethan]

Re: Scott

aaaww bugger it... will have to lift it.. wonder how long it takes to fit the fish finder then... if tis a job that can be donmw while the boat is a) held in air by crane or b) leaning against a quay after the tide goes out... hmmmm will have to think some more....

 

[ccscott49]

Re: Scott

You can lean it against the quay, but make sure you make the fairing blocks first, it takes some time and the tide comes in very quickl;y when you don't want it to!!

 

[Paulka]

I replaced the transducer of my very old Seafarer depth sounder last year. Fortunately, I had a spare one I then bought with the sounder. The most difficult part of the job was the dismantling of the old transducer. Once this is done, cleaning both sides of the hull around the hole is a short job (of course, I used the same hole). I put a generous bedding of Sikaflex, and placed the transducer, not tying the nut too much, to be sure the transducer is not hard on the hull. This would have needed no more than one hour. Actually, I replaced the wooden fairing as well, making a new one.

All together, the whole job was done in about three hours.
Thus could be done drying out with the tide ..... if I were not in the Med!

It now works as new.

BTW, I was then said that the transducer from NASA (?) (not sure about this one) is identical to the Seafarer's one, and compatible.