Measure twice, drill once… really!
There were a couple of threads about that a while back
(standard phrase on this board
)
1. Decide on location (mine as quite far forward so I spent so time watching my boat drive by my dock while on a plane to convince myself that the thru hull would be under water)
2. drill a pilot hole first to double check (it’s easy to plug a 1/8 hole in a fibreglass hull)
3. use a sharp hole saw (I used it from outside and outside alternately so that neither the gelcoat on the outside nor the fibreglass on the inside would chip)
4. dry fit the thru hull and hull valve together first. Make sure there is enough room the swing the valve handle
5. use marine silicon or urethane on the fitting to create a good seal
Info on sealants (look 12 rows down)
http://www.westmarine.com/webapp/wcs/stores/servlet/WestAdvisorDisplayView?advisor=341.htm A “how-to” for replacing thru-hulls on sailboats (close enough)
http://www.c34.org/faq-pages/faq-thru-hull.html