Depthmeter Offset

[Mike Smith]

Breezer is a 1988 Catalina 34, wing keel.  I have a new ST60 Depthmeter with the depthmeter transducer installed in front of and to port of the keel.  I want to set a waterline depth offset to match the depth indicated on charts.  For those of you who have a similar boat/instrument setup, what depth offset do you use?

Mike

PS  I intend to use the "Mark Twain" approach to fine tune the offfset next time we are out, i.e., anchor in shallow water, toss a lead line in the water and read the depth, adjust offset so depthmeter displays correct depth.

[isabel98]

I just use a 1 and a half foot add-on to the indicated depth. not very scientific, but logical and it works..

[Ron Hill]

Mike : Depending on where the transducer for the depth finder is mounted in the hull, I'll guess that it's about 3.5 ft from the transducer face to the bottom of your wing. 
Fine tune from that!! 

[Stu Jackson]

Mike

Don't know if you saw this one: http://c34.org/bbs/index.php?topic=2936.0

[Mike Smith]

Ron -  I dropped a lead line at the dock and it read 7' 9" while the depthmeter read 7.7' with a waterline offset of +2.0.  Close enough for me!

Stu - I did read that thread earlier during my initial search, but thanks for the link anyway.

Mike

[Ron Hill]

Mike : Sounds as though you've got it "nailed" down.