Re: I need a depth gauge (definitions)
Re: I need a depth gauge (definitions)
Semantics are confusing: Hope these definitions will help...........
"Transom-mount" transducer mounts on your transom. They are the easiest to install, readily accessible to maintain, to service and to change equipment to the newest and trendiest of electronics. They are most effective if you are interested in gaining the maximum effective sounding it was designed for and they are the most popular. Changing equipment most always necessitates drilling new screw-holes for the new bracket pattern. Concerns with water intrusion and long term effective sealing are not unfounded.
"Shoot-thru-the-hull" (STH) transducer is most often permanently adhered with epoxies to the top side of the bottom layer of glass on the inside of the boat. Most will install in the bilge or sump and maintain a certain level of water to assist the 'tducer's transmission. Most will install this to eliminate having to drill holes in the transom below the waterline where leaks will occur and to avoid damage to the transducer should it strike a log. "Puck-type" transducers are generally what one thinks of as a "shoot-thru-the hull" style. The (STH) method can be daunting to find a decent location on the inside of the hull to affix. Most fiberglass hull layups are full of voids (air pockets and dry glass mat devoid of resin) which disturb the sonar ping and creates "trash" on your monitor. If the t'ducer is equipped with a speed wheel or a thermometer, they are rendered useless. The effectiveness of the (STH) sounding is most always diminished by having to sound through the glass. Regardless of the shortcomings of mounting (STH), many will settle for a compromise with a (STH) installation if a decent signal can be found. Predominantly; however, most understand at least some of the consequences of drilling holes in a boat hull below the waterline.
"Through-hull" transducer is also a permanently installed transducer which is installed in the bilge or keel of a boat hull. These are generally the most expensive to buy, to install and to maintain. The holes are cut for the particular diameter of the transducer barrel and should a replacement or equipment change be required, either an exact match in diameter or a hull repair and re installation will be required.
Captain Chris
SternMate?
