I bought a used boat a few months ago, and the problem is this:

My graphs will not show depth when I'm running on pad. My old boat did just fine, but I went from a 60hp motor to a 225 (35mph top end to ~64mph top end).

If you have heard of this before, do you know of a good way to fix it?

Thanks!

Edit: Thanks again for all the replies- I'm about as ignorant as a person can be about this stuff. I was out Wednesday and noticed that I lose depth at ~10mph.

You need a through hull transducer bud

What graph are you running?

Mine doesnt show depth while I'm on pad either. Doesn't really bug me I just look at my mapping to get an estimate depth

HDS 10's, gen 2

Now to figure out how much a through hull transducer is going to cost and how bad I want it

Are you not getting a reading on plane at all? or does your reading go away at 45+?

Its been so long now that I honestly don't remember what mph it stops- seems like I remember it going off ~40-45mph. I'm going out tomorrow and will report back.

If you want to shoot thru the hull but keep the temperature reading, you need a transducer with a "remote" temperature probe that goes over the transom. Here's one on eBay that is the model you need:

Lowrance PDRT-WBL blue connector with temp.

Sound crazy but if the glue has any I projections in it this happens. A little water in the hull will help. I was having the same problem and a Hummingbird tech walked me thru testing my transducer. Put it in a bag of water and started working. Redid the epoxy and made sure I hand held it until it set up.

Placement within the hull would be something to verify too. If it is too far to the side, or forward, it may not be part of the pad that really touches water at various speeds/tilt conditions.

Your transducer is not installed properly. The Lowrance web site should have information on the proper installation. The bottom of the puck should be on the same plane as the bottom of the boat.

If the boat is set up properly a transom mounted transducer would have to be the lowest point on the boat with exception to the motor. Fishing Ray roberts with a transducer that low would not be wise. If it currently has a through hull transducer, then I would agree that it's not positioned properly or is not sealed smoothly with the bottom of the boat.

Check the position of your transducer because I do not use a through hull transducer and get a depth while on plane with my Lowrance skimmer.

You've gotten a lot of confusing info above...there's a couple of the posts I don't even understand.

Here's the deal:

If you don't have a thru hull transducer mounted in your boat, then it is reading off the skimmer that is mounted at the back of the boat by the motor. You will lose depth reading at about 8-10mph.

If you do have a thru hull transducer, it's not uncommom to lose depth reading around 45-50mph (less in rough water).

Josh I'm running an HDS-8 Gen2 at the console. I have a LSS-1 box in a rod box and an LSS-1 transducer on the transom. My 2D ducer is mounted in the bilge and shoots thru the hull. I pick up my temp off my LSS-1 ducer so no remote temp probe is necessary. I do read depth off my 2D at full speed but 55 mph is it for me. Willie is right about the rough water causing you to lose depth too. It's nice to have but if I was running that fast in 35 ft. of water and I all of a sudden ran into 2 ft. of water it wouldn't be pretty. I see trees coming up close to the surface sometimes when I'm running but by the time I see them they're already well behind me. So for me it's nice to have but it's going to be too late if you don't have some kind of idea of what your liable to run in to. That's why I run my 2D split screen with my map. I do like it at 15-20 mph for marking things...at least I can fling a marker out the back and probably get back to the bait fish I mark, change in bottom, creek channel, etc. if that's what I'm looking for.