Dead rise

[Yooper]

I’m going to install a new thru hull transducer and I need to know the dead rise at the stern. Can anyone help me with this?
The boat is a 2007 Grady Sailfish 282.

 

[Byram]

20 degrees

 

[DennisG01]

I'm not sure if Grady lists deadrise for your boat in your manual or by downloading it on Grady's site. It seems that sometimes Grady publishes it and sometimes they don't. But that is AT the transom and since you're doing a thru-hull (I assume you mean ACTUALLY thru the hull, not "shoot thru"?) then you're going to be "X" feet forward of the transom. The deadrise will increase as you go forward - although not dramatically in the distance you'll likely be dealing with. But the "X" spot is what you're after, not at the transom.

Most likely, a 20* is what you're after. But you can easily measure the angle if you want to be sure.

 

[Recoil Rob]

I did this on my 180 this past spring. I figured my boat wasn't level on thetrailer or the trailer on the ground so I put a board across the gunnels and measured the angle, I was 2-3˚ off level. Then I measured the angle of the hull at the mounting point and subtracted the first number from the second.
Crucial to the was the device used for measuring, an AngleCube, these things are indispensable...

 

[SkunkBoat]

Most Airmar "Tilted Element" thru hulls come in a choice of 0 deg, 12 deg or 20 deg. You would use a 20 deg on a Sailfish (if you are not going on the keel or a transducer flat)

 

[Recoil Rob]

My GArmin came with 4 tanks of varying degrees.

 

[Yooper]

Thanks to everyone that replied. You’ve confirmed my choice of a 20 degree which covers 16 to 24 degrees.

thanks again!

 

[SkunkBoat]

simple measurement and calculation

Use a level. Draw a horizontal and vertical line on the transom to make sides a and b of a right triangle. The hull is side c. Don't try to go to the keel with the measurement. Its rounded! To get accurate results, make the horizontal line at least 12".
The vertical line must be plumb. It will be 4 7/8" for a 22 degree hull. I just did this on my 2000 265 express. I get 22 degrees which is what I expected.

Roughly 4 3/8" for a 20 deg hull

Because you used a level, the triangle is a right triangle. You can check yourself by doing it again on the other side of the transom.


Use the calculator on the internet. I added some notes to the screen shot.

 

[glacierbaze]

It's not that complicated, measure the hull angle, subtract it from 180, and divide by 2.

 

[Yooper]

Thanks for your response. I’ve ordered my transducer and should have it installed next week.