Need Advice on Depth Instruments and Through Hull

[Pingpro]

Hi everyone. I've been working on rehabbing a 1982 J/24 and have worked through a bunch of projects but I'm trying to figure out the electronics. Particularly looking for a depth finder. There is an existing through hull transducer that's 2" but hasn't been used in at least 15 years. Because I'm in SW Florida I'd really like a depth instrument and would love to use the existing through hull but don't know much about boat instruments. Ill probably set up a small solar system with only the instruments and navigation lights on it. Any suggestions on a cheapish depth finder that comes with a 2" transducer? My priority with this boat is safety and sharpening our sailing skills rather than racing.

Many thanks for any suggestions or insights

Christian

[Joh.Ghurt]

For a 2" through-hole you're probably cheapest with something like the Raymarine i40 or the Plastimo AdvanSea S400. They will set you back around 400 €. If you have a multi-display, you can add an Arimar transducer and again you'll end around this price or more. If you go NMEA 2000, the transducer will be more expensive, but it'll integrate well into the network.

With a smaller through-hole, you could look into the Nasa-mMarine Clipper series, that would save a little, but won't help you here.

This stuff isn't cheap new.

[Pingpro]

Hi Joh.Ghurt,

Thanks for the advice. The i40 was what I was looking at but I will look into the others you suggested as well.

-Christian

[Spot]

Hello Christian,
My boat had nothing so I opted for a lower end GPS/fishfinder loaded with local maps, a Garmin Echomap Plus 43CV and then wired it to talk to OpenCPN. I also have a Ritchie Explorer compass and am making an old-school depth sounding line. None of this solves the 2" transducer thing but the 'bass boat' approach might save $$ over more specific sailing instruments.

[GordMay]

Greetings and welcome aboard the CF, Christian.

[Pingpro]

Thanks Gord May. Also, thanks Spot. I'll consider your suggestion. I'm realizing it would be pretty easy to spend more on electronics than I paid for the boat... gotta have some self control :-)

[JeffDPT]

Just bought the i50. I'm putting it in this week. 2"hole. Instructions seem easy.
Defender has a sale starting Friday. Discounts may help.
Good Luck

[RigBig]

I see these threads about how important knowing depth is. I assume it's about how not to go aground. Of all of the groundings that happen every year, do they only happen to someone who doesn't have a depth instrument? If you are moving at 5mph you are also moving at 7.33333 per second. Can someone explain to me how a depth instrument keeps you from going aground?

[Joh.Ghurt]

If you happily drive along and the depth goes from 10m to 7m to 5m to 3m it's time to become suspicious. This is even more useful when scoping out an anchor-bay.

Another common situation is in narrow channels, where the middle is 5m and the sides below 1.5m. Here with the depthsounder you get a good indication how much buffer you have. If it goes down to 3m it's time to move more towards the middle. It's often more reliable to navigate by depth contour if you're uncertain how accurate the maps are with shifting bottoms.

But you're right, it wont help much when you hit the reef that goes from 20m to 1/2 m. There a depth-sounder won't help at all.

[SVTatia]

You don't need a hole for the transducer, mount it inside the hull, google it for instructions.

And I would cleanup that thru-hull to determine if it is still solid, it does not look well. If after cleanup its kind of pink, either close the hole or replace it.

[Sailon1]

Welcome!
I just went through a similar process replacing old transducer and Fishfinder. You could try using the old transducer. Look at the plug and see how many pins are there. See if they will match whatever you want to plug it into. I also called Garmin and Simrad tech service to help match transducers with fishfinders in depth finder. Good luck!

[Pingpro]

Thanks guys. I agree with SVTatia that it doesn't look well. I haven't started on the project yet as I've been in Fiberglassing and Toe Rail replacement mode. Good to know that Pink = Bad. If I can't use the existing transducer and can't clean and re-use the hole, I'll close it and probably explore the inside the hull option.
Also, related to RigBig's post, I think fewer instruments is ideal, especially for someone like me who wants to hone my sailing skills. I'd rather look at the sails and waves for wind rather than an instrument (at least initially). Speed and water temp is nice to have but it's a little boat and I'm not planning any big trips. Depth in SW Florida is kind of important though in my opinion. That said, the previous owner took it from Naples to the Dry Tortugas with nothing but a compass.

[Cheechako]

Most of my later boats had two. One always a fish finder. The fish finders worked very well and would often shoot (through the hull) to 400 or more feet. So there's that.

[cal40john]

Originally Posted by SVTatia

You don't need a hole for the transducer, mount it inside the hull, google it for instructions.

And I would cleanup that thru-hull to determine if it is still solid, it does not look well. If after cleanup its kind of pink, either close the hole or replace it.

J-24s have balsa cored hulls. An in hull mounted transducer won't work.

[Pillroller]

Nasa make 3 depth sounders here in UK. £99 t0 £140 it would of course add shipping??
£1 approx $1.4 Clipper is dearest and Target 2 cheapest with cruiser in between.