Offset

[LURCHER]

Does anyone know the correct offset for a 150 optimax on a Humber 7m and also where should the cavitation plate be in relation to the bottom of the hull . I think mine is too low .

[Wayne Rogers]

I would have thought a 150 on the back of a 7mtr Humber would be mounted centrally as it is normally on a smaller boat you would offset the engine.I have a 225 on the back off my 6.9mtr and that is fine in the centre,I did however mount my 90 Ficht 2" starboard on my Valiant Patrol to get that to handle correctly,But that was a deep v hull and only 5.2 mtr.As for the height it should be level or slightly higher,the higher you go it will improve top speed but will loose grip from standstill.Mine is up about 3" for speed.
Hope that is of some help

Wayne

[Pete7]

John, you need a bit of time to play around with the height, oh and three lads to change it. If you planning on making that trip next week then I would leave it alone. But start with the cavitation plate at least an inch above the bottom of the hull, I am assuming you have a S/S prop.

Ignore the offset unless it handles crap, you will only have another set of holes in the transom to worry about. I did move a 150 Mariner from 2" to Stbd back to the centre line with no ill effects on a 6.5m Ribtec.

Pete

[LURCHER]

Thanks Pete , I have already lifted it off solo and don't intend to do that again at the moment ! The transom is like Swiss cheese with all the previous holes from other engines and I now find that it has been cut down to accomadate a short shaft at some time and it was not done square. Winter job is to remove engine again and make good transom with a stainless or ally plate then re mount engine .