transducer help

sheldon6 · 29 May 2009, 09:57

OK, thanks to you guys i've deceided upon garmin 550s, best price I found was 421.00, phoned to order then i was asked if i wanted a thru hull or transom mount transducer err err i'll phone you back was my responce, now its over to you for your input???

geoffs · 29 May 2009, 10:20

Thru hull involves finding a suitable spot well aft and drilling a gurt big hole through your hull then fitting the transducer through that. Transom mount means finding a suitable spare spot on the bottom edge of your transom and screwing it on there. The other option is in hull, where you bond the transducer to a single skin section of hull aft and it pings thru the hull to the water.

If you go to the airmar website, you will find the pictures and installation instructions for all three types.

AndrewH · 29 May 2009, 10:40

Also worth noting that transom mount is a bit more vulnerable and can be knocked whereas the thru hull is more protected. Also, given the transom's position, you are only ever measuring the water depth at the back of the boat. That's OK if you are reversing into the shallows, but not much good if you want to know what is under the bow. In contrast a thru hull can be mounted anywhere on the hull provided you have access and that part of the hull is flat, so you may in theory be able to get it quite close to the bow.

The downside is access, you have to able to get to, and fix the transducer. For this reason alone - I've always gone for transom mount

Pete7 · 29 May 2009, 10:48

Just make sure that price includes the transducer, Marine Superstore are £449 and are very competitive on price, which makes me think the £421 is without.

Pete

Andy Young2 · 29 May 2009, 10:50

Following advice on this site I tried the third way; using the transom mounted transducer fixed internally. In my case I used a tupperware container suitbaly stuck to the inside of the hull (without bubbles) and filled with vegetable oil. Transducercommfortably held in place in the tub by a plastic coated 1kg divng weight in a tupperware that was a very close fit all round. Tupperware was the type with O ring that has external clips which once popped down I secured with cable ties. Works for me.

Having said that I knackered an ali prop today however I was 150m offshore in 13 feet of water and think it was a unmarked piece of concrete swept out from the Muscat shore during the cyclone Gonu a couple of years ago and hence unmarked. Unwelcome, but I hope it hasnt caused gearbox damage. Heavy vibration on tickover but hopefully its the prop not transmission elements further up. Will strip the prop as a starter and price two new ali props sadly it means air freight from US as no local delaers for Johhnyrude. Am in Dubai/Abu Dhabi next week so may try to grt there.

jyasaki · 29 May 2009, 15:21

Quote:

Originally Posted by AndrewH

In contrast a thru hull can be mounted anywhere on the hull provided you have access and that part of the hull is flat, so you may in theory be able to get it quite close to the bow.

Make sure it's in a portion of the hull that is in the water at speed, else you'll only get readings at lower speeds. That generally means further rearward than you might imagine.

Does anyone run switchable transducers? One at the stern for high speed, and one at the front for shallow water apps? (Actually a moot question for me, as I have yet to see a transducer that will shoot through 1/4" aluminum plate.)

jky

sheldon6 · 29 May 2009, 15:49

Quote:

Originally Posted by Pete7

Just make sure that price includes the transducer, Marine Superstore are £449 and are very competitive on price, which makes me think the £421 is without.

Pete

Just phoned Marine Superstore, their price is without the transducer wich is an additional 49.49

Pete7 · 29 May 2009, 20:25

Ouch

Chris · 30 May 2009, 18:05

Sheldon,

Fit a transomm transducer, I disagree with fitting it further forward its fine on thebback and as its just next to the engine it is going to tell you the depth of water below the prop which to my mind is what you want to know.

I have had transom mounts on my last two boats and apart from when I tried to use one as a foot step to get into the boat and broke the mount I have had no problems.

BTW I got the new one off eBay for about £20 so if they do break they are not too bad to change anyway.