Setting Keel offset on new Transducer

[Dobey1]

Added a new Garmin Transducer GT22 to a 1040xs. For some reason the previous owner had a non Down-view transducer on it, no idea why he wanted to save $20- 

Anyhow the keel offset was at -1 should it be negative or a positive number? Transducer is mounted on Transom in the standard PF transom location.

 

Thank you in advance for your help.

[hurricane]

I would assume 0 if it's transom mounted. The keel angle shouldn't matter if it is mounted level with ground. 

[smilemaker]

The way I understand  keep offset is that it is used so that the reading on the screen is the actual water depth. I want to know how much water is under the boat not how deep it is from the surface so I have never adjusted for the transducer location

Usually a negative number is used to tell the unit the transducer is lower than the reading you want. 

A positive number tells you the transducer is higher than the reading you want to see and is usually used on sailboats to know how much water is actually under the keel or the bottom of the boat.

If the  original  owner has a negative number  then it was set up to give you  the  actual  water depth so you have less water actually  under the boat. Not the setup I would want.

[fin-addict]

Would not use a keel offset except on a sailboat. Jmo.

[jh141]

My understanding, fir what its worth.  The boat off plane, the transducer is maybe 10 to 12  or so inches below the water. So the depth your unit is giving you is actually 10 to 12 or so inches deeper. On plane that Depth accuracy again would change, the transducer would be More accurate. (closer to the actual surface). On a vessel with a large adjustable keel (sail boat) this could be critical. Not so much on a bay boat.

I am with SmileMaker, I leave mine at zero because I want to know in any instance how much water is Under My Boat.