[Public-list] hull thickness

[The Rochets]

I  am interested in the Raymarine ST40 depth sounder. It comes as a  
package with a thru-hull transducer, but I want to install it in a  
waterbox, in-hull. Raymarine has assured me it's OK to use the  
supplied thru-hull transducer as an in-hull as as long as the hull is  
no thicker than 1/2". Do we know what the thickness of the hull is  
under the cabin settees about 6" away from the center line (that's  
where I am thinking of installing the transducer)?

I know the answer to this question is somewhere in the list archives,  
but I am having trouble searching the archives. A simple search  
returns no hit regardless of the search term, including terms like  
"coamings" which I know have been discussed fairly recently. I also  
tried a Google search within the archives domain (http:// 
lists.alberg30.org/pipermail/public-list-alberg30.org/); I have used  
it this method before, but right now this doesn't work either. What  
am I doing wrong?

Thank you.

Bernard
Sunswept #608