Depth Finder

[Gordy]

Sawdust, my Core Sound 17 wants a depth sounder.

Since it's an open boat, it will have to be mounted well forward to be out of the way. We're talking just under the little forward deck, about seven or eight feet from where I sit. Big numbers are good.

I'm leaning toward the bottom-of-the-line Hummingbird fish finder. It has big numbers, a waterproof housing and costs less than a pure depth finder.

For power, I have a motorcycle battery that I intend to make a home for.

My boat is plywood. I've heard that I can mount the transducer by just sticking it in an appropriate size puddle of epoxy. The epoxy and plywood will be invisable to the transducer.

There should be no air bubbles in the epoxy.

Have I gotten it right?

This link will get to an album page. Sometimes my album is up, sometimes you have to look for it.
http://www.messing-about.com/smallboats/albums.htm

[Pete Dorr]

Sounds right.

I have the same Hummingbird for the same reasons. I did a transom mount because it was easier.

I keep it on the boat but keep my gps with me as it was a lot more $$.

[Gresham CA]

Gordy,
You can not shoot a transducer through plywood. With wood you will need to cut a hole near the centerline of your boat or mount it to the transom, assuming that the transom stays in the water all the time.

Just looked at your boat, you might need to get out the hole saw.

[ 12-10-2002, 10:46 AM: Message edited by: Gresham CA ]

[Donn]

Charles is right...wood will scatter both the outgoing and incoming signals. You'll get some return, but not enough to be reliable.

[Memphis Mike]

I wouldn't cut a hole in that boat.
If is was me I'd get a trolling motor
and mount the ducer to it.

[Hugh Paterson]

Whats an echo sounder? Why not use your boathook or Mk one eyeball ;) Strikes me in a 17 ft boat if its that shallow you will be stepping shore anyway, what yr draft?
Shug

[Rocky]

Get a nice reconditioned unit from www.humminbird.com (http://www.humminbird.com) for $75. Probably have to hang it off the transom.

[Tom Lathrop]

It is not difficult to mount an inside depth sounder on a wooden boat. Cut a hole in the bottom at the desired location and chamfer it on both top and bottom. Fill the hole with layers of glass and epoxy. An easy way to make the surfaces fair is to clamp or wedge a smooth flat material with a plastic shield against both sides.

I made a wood block in the shape of the transducer, covered it with plastic tape and forced it against the epoxy on the inside. The transducer can be glued in place with epoxy or silicone but be careful not to allow air bubbles into the mix. You can level the transducer at this time if wanted. Do not use any thickeners in the epoxy since the this will introduce air bubbles and the thing will not work well, if at all. Spent a frustrating hour figuring this out.

Works fine through the wood bottom and allows you use the transom mount transducer that comes with most units instead of shelling out more bucks for the through-hull unit.

[ 12-10-2002, 01:34 PM: Message edited by: Tom Lathrop ]

[JimJ]

Gordy

I have the transducer for a depth sounder shooting through a plywood hull. To make matters worse, it is held in place with Silastic.

It does not seem to affect the performance of the unit. The greatest depth I have seen so far is 140 feet.

Do this to try it through your hull.

Locate the boat in a known depth of water.

Try the unit outside the hull by placing the head of the tranducer in the water and turning the unit on. Record the depth indicated and position of ant adjusting controls on the unit.

Pour some water into an area of your hull deep enough to cover the head of the tranducer.

Place the transducer vertically in the water. Just hold it there by hand.

Turn the unit on. Adjust the unit controls as per the unit's manual if required.

If it works, compare the previous depth and position of the controls.

If it does work and you are satisfied with the readings, locate the unit inside the hull with RTV where required. Make sure there are no air bubbles in the RTV. Push the head of the unit against the hull and rotate it slightly.

Give it ago. It may save you cutting a hole in the hull.

I have put mine through the hull as I beach my boat and would prefer not to have a transducer head outside to get damaged.

[Donn]

JimJ...if all you need is depth, that might work, but if you're after more detail, like bottom condition in an anchorage, or any thing having to do with fishing, it just won't work well. Plywood is even more difficult to shoot through than solid wood, because of the alternating layers of high and low density material. A gross example of the theory is the difference in the distance sound (sonar) waves can be transmitted and echoed through air and the distance through water.

[Memphis Mike]

No manufacturer advocates locating the
transducer inside the hull. But go ahead
and give it a try. ;) I will tell you
this, when I bought mine, Donn advised
me on its installation and it works
perfectly.

[ 12-10-2002, 08:04 PM: Message edited by: Memphis Mike ]