Angle Thru hull transducer on 2001 21se?

[grasshoppper1]

hey guys,
Im looking to install a airmar 175hw & L on my 2001 21 se. But im not entirely sure what angle I’m supposed to get. Anyone have any idea that’s done it before?

 

[Postal719]

What's the dead rise? They make a 0, 12 and 20. 20 for deep v boats like mine. Installed in the rear hatch where there is clean water.

 

[warthog5]

How to know your deadrise.

This is done with boat on a trailer. First you will need a angle finder.

A cheap one from Harbor Freight. https://www.harborfreight.com/dial-gauge-angle-finder-34214.html

Lay under the boat at the transom area. Take a reading on Port side and write that down...Take a reading on STB side and write that down. Add them together and then divide by 2. That is your deadrise angle. It will compensate if the trailer is sitting at a angle.