There are lots of choices for boat instruments; however, the Raymarine ST40 is the only installed instrument I need. My Handheld GPS gives me everything else.

The ST40 display has two types of transducers; the Thru-Hull and the In-Hull. The first requires that a hole be drilled in the bottom of the boat, the latter is the shoot through the hull type and only works with fibergall bottoms and placement of the transducer is critical.

The AIRMAR Model P79 transducer is available from Raymarine and does not require a hole in the boat. Go to the Raymarine website to find out more about In-hull transducer: http://www.raymarine.com/raymarine/Default.asp?site=1 and Section=2 and Page=606 and Parent=40

On the H260 the location next to the bilge pump is the preferred location. Raymarine says the transducer should be epoxied to the hull but some people have just used toilet ring wax to stick it to the bottom of the bilge. That makes it removable. I used the wax to test it first then after I was sure it would work, I used 3M4200 sealant to secure it in place. I installed the transducer next to the bilge pump. It has worked without a hitch. The install instructions are easy to follow. In-Hull Transducers. My transducer reads to about 300 ft. Below that youll need to go to a thru-hull transducer. However, since my major concern is rocks, the fact that I cant see below 300 ft is not a concern. More info from the Raymarine website: In-hull (a.k.a. shoot-through) transducers are epoxied directly to the inside of the hull. These are only used in fiberglass hulls. In-hulls will not work with wooden aluminum, wood, or steel hulls, or in foam sandwich or hulls that have air pockets. Any wood, metal, or foam reinforcement must be removed from the inside of the hull. With an in-hull transducer, the signal is transmitted and received through the hull of the boat. As a result, there can be considerable loss of sonar performance. In other words, you wont be able to read as deep or detect fish as well with an in-hull transducer as with one thats transom mounted or thru-hull mounted. Fiberglass hulls are often reinforced in places for added strength. These cored areas contain balsa wood or structural foam, which are poor sound conductors. The transducer will need to be located where the fiberglass is solid and there are no air bubbles trapped in the fiberglass resin. Youll also want to make sure that there is no coring, flotation material, or dead air space sandwiched between the inside skin and the outer skin of the hull. Advantages: No holes drilled in hull Excellent high speed performance No obstructions in the water Low maintenance Disadvantages: Reduced maximum depth reading Reduced fish detection Can only be used with fiberglass hulls Bottom Line: Very accurate and reliable and ideal for the H26/260