I want to put a depth sounder w/a shoot through transducer on my 28 cig. I have been told that Gaffrig models will not read depth past an idle speed and that other brands would read at any speed. Is this true? if so what would be another good manufacturer to use?

Well, the Gaffrig unit is made by Hummingbird. Now there are only 2 companies that make depth finders. So if Hummingbirds don't read past idle, then there is only one brand that will work. If somebody had only a 50/50 shot at getting a depth finder that would work, then we would be hearing alot more about these infernal things. So, I'd have to say that your source is quite wrong. My experience has been that they don't work over 65mph. I've heard that they won't work once air starts getting under the hull. I also know that they will not shoot through coring. Most people will cut the coring out in that area.

Cord is right, especially the coring issue. You may not want to cut into your hull if does not have non cored area built into it.

I bought shoot thru Hummingbird last year and played with it for a long time but couldnt get it to work for s**t. Sent it back & got one that mounts on the outside of transom. It works great even at 66.7 MPH.

Bo

I have a Lowrance 3400 that shoots through the hull just fine at all speeds as long as the hull stays in the water. However, my hull was built with a spot for the transducer (no coring in a small area) and it is not a step hull. Through hull transducers do not work well at higher speeds on step hulls because of the aeration caused by the step(s).

Cord, only two? Who makes Lowrance, Standard Horizon, Uniden and Datamarine depth finders?

On a stepped hull the transducer has to be in front of the step. I've done this on two different Formulas(solid fiberglass hulls) and it works at all speeds.
DaveHam

My Hummingbird reads up to about 50 mph then is loses the bottom. I suspect that this is because there is too much of the hull out of the water. It is in a 280 Velocity and mounted just forwar of the motor. I did have to cut the core and "pot" the transducer, not as bad a job as it sounds.

laster-your right. I was thinking the same thing, but I was limiting my comments to only the 2-5/8" round dash style like the gaffrig unit. I was going to say three mfr's, but then I remembered that Telflex ownes Hummingbird.

do any of you guys know where to mount a shoot thru on a 27 Fountain with a step hull?

Indy,

Mine is mounted under the step as you walk into the cabin. As mentioned, if you have a stepped hull, it is in front of the step. It works 'till about 60-65mph. I wonder if it is set differently though. It is obviously not the lowest part of the hull in the water.