International Telstar Owners Association

I plan to fit a new Raymarine GPS/Sonar on my 1978 Telstar 26. But the question is which Transducer to fit?

It depends on how the hull has been constructed. I've read somewhere that the boat is made with a sandwich construction, which means I'd need a through hull transducer. However somebody else told me that the hull is a solid lay-up of GRP - (only the decks and cabin roof are a balsa sandwich construction). If that's true then I can use an in-hull transducer which is what I'd prefer

Can anyone offer advice?

I was just hoping that somebody could tell me with any certainty if the hull of a mk2 Telstar 26 (1978) was solid GRP or sandwich construction?

The hull is solid not sandwich construction

core is usually used in decks about the water line that need more stiffness for the point loads of feet. few core below the waterline because it can waterlog.

i can confirm that ! i have a through hull sensor and it's off the boat so i can see clearly the material in depth ...it is solid fiberglass but is like 10mm thick