What angle thru-hull transducer do I need?

[billh1963]

I'm ordering my depth finder this week and will be using a thru-hull transducer. It will be mounted a few inches off the keel center.

The transducer should be mounted so that the beam shoots straight down. Since the hull surface is at an angle at that point, does anyone know what the angle is for a 19-6 (same as a 20) hull? The boat is 4+ hours away so I can't measure it myself...hence the question.

Thanks!

[scott_gunn]

12 degrees deadrise, so if it's mounted near the transom, 12 degrees should be good.

[billh1963]

Thanks, Scott. Is that what deadrise means? I had always thought it had something to do with the angle of the bow. It just goes to show you can learn something every day!