We had a 12 foot tinny years ago and we just epoxied the suction cup to the hull. We couldn't get it off when we scrapped her. I believe a suction cup will work if epoxied well on a clean section of tin or glass. I wouldn't want to drill holes in a new boat either. Or an old boat for that matter.
Now that ive read the garmin faq on transducers I will never drill again.If they say thru hull is ok with my ducer I believe them.Teaches me not to read the whole manual,lol.
Man I'm having big troubles putting a link on today.Any who garmin says under faq ,transducer types, that the plastic transducers can be used as transom or thruhull on glass and tinnys.Wood is a different story.So Texasmark your correct my friend.
Thanks. I will have to admit my first knee jerk reaction to wanting to mount one inboard (because fishing the logs and brush, and getting kids into the boat when skiing kept the external bent or knocked out of the holder constantly) I hesitated on the metal hull, but I had my RADAR electromagnetic wave theory hat on. Once I recovered my senses and remembered that we are dealing with sound waves, it was a no brainer.