Depth/speed sensor options.

[OneBoatman]

MerryDolphin Good to know the inside the hull transducers work well on solid glass boats. My Pearson 386 has about 3/4" of solid glass where the original thru-hull is located about 18" forward of the keel. In all my years of sailing I've never seen these leak. Of course It is important that the inner hull be flat and as close to perpendicular as possible to the plane of the seat on the outer hull. On boats I've installed the thru-hull I dril the hoe ~3/16" larger than the stem major diameter and then coat the exposed glasse in two separate mixing step using resin and micro-ballons letting each one cure to minmze clearance before installing the thru-hull fitting. I clean the inner and outer seat zone with laquer thinner and use polysulfide type sealant for the final install. I also haul the boat annually and check that thru-fitting tube and O-ring land is in good clean condition. Then apply a light coat of Dow Corning silicone grease to the O-ring.

[mako]

Originally Posted by OneBoatman

On boats I've installed the thru-hull I dril the hoe ~3/16" larger than the stem major diameter and then coat the exposed glasse in two separate mixing step using resin and micro-ballons letting each one cure to minmze clearance before installing the thru-hull fitting.

Okay, I don't get this. Why oversize the hole then fill it back in? You could either drill the hole proper size and tight, or slightly oversized but coat the entire stem with bedding compound/sealant as you insert the transducer, thus having three surfaces for water tightness (exterior sealant/O-ring, steam sealant, interior sealant/O-ring).

[Rumrace]

Great Lakes so anti-algae wax seems to survive a season.
I like forward looking fish finding stuff. We are, have been wreck divers for some time. Our first GPS way points were all shipwrecks. When I saw a map of one of the wrecks I visit in colour 3D I was in love love love. Folks use their iPads but they don’t like the sun. Ours is at the nav station beside another plotter running entertainment via a wisa broadcast system.
We do have some oddball homemade electronics my grandson and I made. Raspberry 2 cameras a servo shield 8 relays 2 stepper motors and I 3D printed a water proof container for it. We made a dissolved oxygen sensor on a breadboard. It was really interesting.
Kudos to you if you can make all that stuff work and show up on the screen.
We have name brand no issues at all. We have not added radar but it’s a consideration.

[OneBoatman]

Mako - Applying polyester, vinyl ester, or epoxy systems to re-seal the laminate where you may drill a large hole in the hull is pretty common when installing thru-hull fittings in 4 seasons climates. Many folks also do this when fastening their deck fittings such as clutches, windlasses and other areas they tend to. All done before any bedding compound is applied. I believe it is particularly important for cored laminates. Moisture can accumulate to the low points and freezing any laminate with high moisture content is a recipe to weaken the hull locally. I guess you could argue that osmosis happens eventually anyway and it may not effect you if don't you plan on keeping the boat very long. And then maybe its just superstition.

[mako]

Okay that makes perfect sense with a cored hull or deck. Maybe I missed that part of your original post. How about with a solid fiberglass hull - would there be an advantage to still employing that practice?

[MVDarlin]

I recommend a in hull transducer connected to a depth and chart plotter combo to start. Next time the boat is hauled install a robust transducer for other bells and whistles, new transducers give you water speed and temp without a paddle wheel.

[OneBoatman]

MVDarlin could you tell us which transducers give you speed through the water without a paddlewheel. The transducers I am familiar without paddlewheels that interface with chartplotters aren't able to tell you anything about what the water is doing and only give you speed over the "ground" or distance traveled over time as calculated by the GPS function.

[El Pinguino]

I've never had my Airmar paddle wheel suffer from fouling when sailing - only when sitting in a marina for an extended period.... and that can be fixed with a quick scrub with a toothbrush - not mine - hers

And it is always removed when getting lifted out.... pretty dumb not to do that.

[Tupaia]

Originally Posted by OneBoatman

MVDarlin could you tell us which transducers give you speed through the water without a paddlewheel. The transducers I am familiar without paddlewheels that interface with chartplotters aren't able to tell you anything about what the water is doing and only give you speed over the "ground" or distance traveled over time as calculated by the GPS function.

https://www.nasamarine.com/product/electromagnetic-log/