Kermit sent me a link to this. The best place to put a thru hull transducer is adjacent to the bilge pump under the rear berth generally to the left of it as you are facing toward the rear on the flattest spot. If thru hull, measure the fitting which generally is close to a 2 inch hole and drill thru. Remove any paint on the outside where the flange of the fitting would go over the hull and sand the gel coat for good adhesion. Liberally apply 5200 on that fitting to include the flange area and push in.. Tighten the collar down as far as it will go without turning the fitting and let the 5200 dry for 7 days. Do clean up the excess 5200 using alcohol. You will need to clean the area inside and wipe down with acetone on the fiberglass. When you turn down the locking collar, put a dab of silicon on the threads, not 5200, to help to hold that collar fast. Make sure the arrow points forward
You could instead clean the area inside first, sand it as smooth as possible and clean again with acetone. Then take plummers putty and a lot of it and immerse that transducer down noting the arrow to show forward and pack the putty around and let stand until it drys. Kermit made me a believer out of that.
As for speed, the GPS is good on that. I always hated to remove the speed transducer to clean it often as you generally cannot place anti fouling paint on top of it but you can on the depth transducer.
I never cared for the fish finder gadget attached to the transom.
