8 years ago, we bought a Coronet 26 Family Sport (year of construction 1979) which is equipped with two AQ 170/280, 15" propellers. Our Coronet shows a water displacement of approximately 3.500 - 3.700 kg. Originally, the boat provided 17" props and our Coronet reached a speed of approximately 30 knots with her 17" props. But after 960 hours of operation, the engines got too weak and we had to replace the 17" props.
Now, we would like to replace the enginges with 3.0l MerCruiser with approximately 140 hp and Alpha drive. We heard that one time, Coronet offered the 26 Family Sport with this motorization, the manufacturer was Volvo Penta.
Do you know any answer to the following questions:
- would this motorization be technically feasible?
- what do we have to keep in mind if we decide to replace the engines?
-which transmission ratio should the engines provide and what size should the propellers be in order to get the boat to move fast but not wasting too much fuel?
- do you have any idea which performance could be achieved (e.g. Coronet 26 Sport with two engines (gasoline), 4 cylinder Volvo Penta)?
- the boat´s shell is twisting quite heavily during moderately rough sea, which can be noticed at the wooden frame of the cabin door. Is this ok? The force is even opening cabinet doors, screws are falling our, etc.
- Do you know anybody, who is still selling spare parts linke windows, skylights etc.?

If you have any experience, we would appreciate an e-amil to: info@lrc-muenchen.de.
best regars - Petro