Miss matched hull and motor

[Platycephalus]

Anybody out there been advised that the motor fitted to the boat is an unfortunate miss match. Have a Quintrex Bass 3.9 m (1992) fitted with a short shaft Mercury 20 hp (1996). All the measurements and specs indicate that the should be no problem but as soon as the hull is unbalanced on one side or another or in moderate turns the prop cavitates. Makes for an unpleasant journey when there is any cross chop. Other than cutting a lump out of the transom and letting some more water over the back or changing the hull, any suggestions? :(

[Mr__Bean]

Would be worth having the prop checked.

I would contact Solas propellors and seek their input.

- Bean

[finga64]

what about some foils to try to stop cavitation and nasty handling??

[Big_Kev]

Some 3.9 hulls are made to suit a long shaft outboard.
Are you sure you have a short shaft version? :P

[Platycephalus]

All the measurements check out for short shaft.

Have taken earlier advise and contacted Solas, they are pretty sure that extra cupping in the prop will solve the problem after I described the symptoms. Have sent it away today so will provide an answer to those interested in a week or so when I can "water" test it.
:)
:)

[dnej]

How much is it costing, to cup the prop?
David

[Platycephalus]

dnej
Service from Solas spot on, had the prop back withing three days cost <$45 including freight. Haven't tried it yet but was worth a go. Next stop new hull if thjis doesn't work

[Platycephalus]

Was able to take the boat out for its first test run on the Logan R this morning to test out the prop after cupping by Solas. Pleased to find that what externally appears to be only a minor bending of the upper edge of each blade has done the trick. Would say that the performance is now about 95% of what you migt expect as normal. Small loss of grip (no cavitation) in moderate turn at 80 % full power. Morning was too good to test in any rough weather but the bow waves of all the trawlers around Pitts Rocks certainly made some side swell.

Took the rod and SPs for a flick around at the mouth and was rewarded with a 55 cm flathead and a couple of smaller ones in a short session.

Alls well that ends well!!!!!!!!


Cheers

[noluck]

::)I think it is just quintrex