Garmin 'In-Hull' vs 'Thru-Hull' Transducers

[La Bras D'or]

Hi everyone - I'm learning a lot here since joining, thanks !

I've ordered a Garmin 545 GPS/Sounder for my boat (Beneteau 361) and I'm having trouble deciding on a depth transducer.(salt water usage) The new system ordered, allows for a dual frequency 50/200 kHz transducer and I have several options.
-Can I use my existing Raymarine transducer attached to my ST60 Tridata or must I install a second one dedicated to the Garmin 545? If I can, how do I interface it?
-If I need to install a new one, has anyone tried using an in-hull type(epoxied to the hull inside) instead of a thru-hull?
-Is there one that will also provide temperature to the 545 and is there
any difference in accuracy between the two types?

I hate to drill holes in a boat - especially below the waterline.

[SeaKing]

Make a "well" to put the transducer in. I have worked on many survey vessels that the transducers were in compartments filled with liquid . My last sailboat had a "well" build with 4" PVC pipe glued to the hull and the round thru-hull Plastic garmin transducer just set in the well and a cap was on top of the pipe. The pipe was only 3 or so inches tall. It worked fine with a Garmin 178c sounder plotter. The mounting in a well will allow you to have the transducer pointed down straight and not slanted with the hull "flair"

[David M]

Generally, transducers are not interchangeable with the sounder. There are too many variables between transducer heads. The chances of all the variables matching what the sounder requires is very remote.

[FrankZ]

Originally Posted by La Bras D'or

Hi everyone - I'm learning a lot here since joining, thanks !

I've ordered a Garmin 545 GPS/Sounder for my boat (Beneteau 361) and I'm having trouble deciding on a depth transducer.(salt water usage) The new system ordered, allows for a dual frequency 50/200 kHz transducer and I have several options.
-Can I use my existing Raymarine transducer attached to my ST60 Tridata or must I install a second one dedicated to the Garmin 545? If I can, how do I interface it?
-If I need to install a new one, has anyone tried using an in-hull type(epoxied to the hull inside) instead of a thru-hull?
-Is there one that will also provide temperature to the 545 and is there
any difference in accuracy between the two types?

I hate to drill holes in a boat - especially below the waterline.

I have the Garmin depth sounder with the in hull transducer. It seems to work fine for me. You need to be sure you have a solid hull, no core. There is also a thickness maximum but I don't remember what it is. The transducers are made by Airmar Ultrasonic Air Products and you can get the manuals from there to have a look before buying.

My only problem with mounting was find a place that I liked (out of the way, near centerline but not too close to the keel) that met the angle requirement of 22.5 degrees or less.

I am not really happy with the spot, and I keep thinking of moving it but it works so it isn't a priority. Getting out for a sail, that's the priority.

[sandy daugherty]

I'm afraid you will have a conflict between your Raymarine and Garmin transducers because they both operate at the same frequency. You will need to wire switches into the hot lead to each transducer to turn it off while you are using the other one.

[forsailbyowner]

I went with a furuno smart sensor transducer. It speaks in nmea language standalone so it interfaces with just about anything. It reads speed, temp and depth and the core can be removed from inside the boat for cleaning and when the boat is stored.

[pirate_222]

I've been using a "in-hull" set up for several years on two different boats and never had any problems with it.
That said, just be sure the unit/transducer has enough power. With the Garmin that shouldn't be an issue. I just upgraded to a Garmin GPSMAP440c and the 'ducer works great mounted in my pvc well like SeaKing said. Prior to purchasing the Garmin and upon the failure of my last sounder, I got an el cheapo Hummingbird from a big box store. (Heading out for July 4 with eight guests aboard, great timing, aye?) The power output was not enough to get thru the hull at anything other than tied to the dock or sitting on the hook. As soon as the boat started to move, goodbye signal.
My "well" is a 3" PVC pipe, mitered to fit the curve of the hull,epoxied, filled with mineral oil and capped with a hole thru the top for the 'ducer cable.
The temp reading is the temp of the mineral oil in the well.
Hope this helps!
Dave

[La Bras D'or]

Thanks everyone for "sounding" in here.
The "sump" or "bath" Idea seems to be everywhere now that I'm looking for it. Seems like a better idea than drilling a 2" hole in my boat - Again!
I've been talking to a number of people through the week around the marine store and marina here and there seems to be a strong consensus that I would be better staying all raymarine instead or using a Garmin Plotter. So, I've put the Garmin Plotter on hold and looking again at the C70 Raymarine instead and that way I will avoid the transducer problem entirely. I'm sure many of you out there have or knows someone who has this one or one of its bigger screen sisters the C80 and C120. Any one having trouble with theirs and/or have some advice for me on the decision?

[perchance]

I mounted a fish finder/depth sounder inside the hull (don,t like holes in the hull) using 5200 as per store guys advice. Works like charm.I'm one of those guys who like to see the bottom contours Thus the fish finder and mark a lot of fish while sailing. I made a dam out of cardboard and filled it with the goop till level and mounted the transducer. You have to keep air bubbles to a minimum as this interferes with the signal.

[AnchorageGuy]

Your Raymarine transducer is not going to work with your Garmin so why not just put the new transducer where the old one was? The water temp will not work inside the hull. It is called water temp because it needs to be in contact with the water to give you the temp. If you are going through all this expense and effort why not do it right?

[David M]

When responding to threads, it is always helpful to check the date of the original post and the date of the last post. In this case, this thread was created on July 30 2008. The guy who created the thread probably hauled out months ago and is back in the water with his new transducer already installed.

[SeaKing]

Originally Posted by perchance

I mounted a fish finder/depth sounder inside the hull (don,t like holes in the hull) using 5200 as per store guys advice. Works like charm.I'm one of those guys who like to see the bottom contours Thus the fish finder and mark a lot of fish while sailing. I made a dam out of cardboard and filled it with the goop till level and mounted the transducer. You have to keep air bubbles to a minimum as this interferes with the signal.

I don't think I would have used 5200, I will have to experiment with some other easier to clean up stuff. Maybe the 4300 ( i think that is what it is), for a more temporary permanent install.

[Ziggy]

Originally Posted by David M

Generally, transducers are not interchangeable with the sounder. There are too many variables between transducer heads. The chances of all the variables matching what the sounder requires is very remote.

That's not entirely true. The vast majority of OEMs, including Garmin, Furuno, and Raymarine, use the same Airmar transducers. The cable connectors, on the other hand, tend to be unique to each OEM. The Airmar P79 (Garmin Part Number: 010-10327-00) in-hull transducer works very well.

[AnchorageGuy]

Originally Posted by Ziggy

That's not entirely true. The vast majority of OEMs, including Garmin, Furuno, and Raymarine, use the same Airmar transducers. The cable connectors, on the other hand, tend to be unique to each OEM. The Airmar P79 (Garmin Part Number: 010-10327-00) in-hull transducer works very well.

Yes they all use Airmar transducers because Airmar makes all the transducers but they are not all the same and they are not interchangeable. There are different Airmar transducers for different Furuno sounders. The same for some other manufacturers.

[Badsanta]

I would leave the tri data system alone and then just install the garman separately and not try to inter connect them, since you already have it. This would lead to two depth sounders and would not likely for both to fail giving some easy redundancy. I also have the ST60 system and was having trouble interfacing with my new garman chart plotter. I know they can be interfaced, but I like the two standalone systems.