Looking to upgrade my ancient lowrance depth finder on my 1989 242ss.... I know this topic has been discussed in the past... but wanted to see if there was any experience with the formula owners here on the Shoot Thru transducers, being that other boat brands/models have different hulls hence different readings/opinions... are they accurate? effective? What do you lose by not going with transom mount?

Your thoughts/experiences would be much appreciated...

My personal opinion - the less times I have to drill through a transom, the better....

Installed the 3800 in the FASTech, works just fine shoot thru. I did purchase separately a dual sensor, one for depth and one for water temp though. Still have the original transducer that came with 3800, it can be mounted on the transom, or glued to bilge for shoot thru.

I just bought a Garmin IN-hull transducer from West Marine. I did a bit of research here and was told they will work fine in our hulls. It is not installed yet so I can't give you first hand info .

Great thread...I am watching this closely.

I replaced the factory in-hull transducer with a Airmar P79S that is compatible with SmartCraft (I have the SC5000 System View). With my stepped hull 292 the transducer is installed forward the first hull step under the stepdown entrance to the cuddy cabin. If mounted behind the hull step the water is aerated and causes inconsistent readings while underway.

With the Fastechs the fiberglass innerliner must be cut-away to expose the outer fiberglass hull layer. The P79S housing is then siliconed to the outer layer and filled with mineral oil. The tranducer attaches and is sealed to the housing via the cover. This transducer works MUCH better than the factory one. Consistent depth readings even at 70 mph as long as the boat is not airborn.

http://www.airmartechnology.com/2009...id=79&manf=All

One note in placement:

Where ever it is placed keep in mind, that depending on your speed, that is where you where seconds ago. Just like when we were flying with radar altimeters, it was where you where 8 - 10 seconds ago. Mine still works behind the step (factory install) at speed, however I really don't care what the reading is, I use it mostly for idle around docks and marina's. Keep in mind I boat on the same lake. Depending on your use, you may want charting software to aid in your navigation. .02

Good point...my bilge has a full inner liner with no direct hull access. I am going in the front "mini-bilge" below my cabin step...clear hull there.

IMO this is a good location. Plus easy access.

My 292 has an inner liner covering the entire bottom (fiberglass reinforcement grid). The factory transducer was already installed forward the first step in the hull under the cabin step. The inner liner was cut-away but had to be enlarged to accomodate the P79S.

I like getting depth readings from this location. It is about 20' forward of the props. We anchor off beaches on the river and when slowly nosing in along the shore I get the depth ahead of the props then drop anchor.