Quote:
Originally Posted by 2sledge
morning and thanks for letting me join your group
new to boating
been given a seapro 470 that was bought off bill higham by my father but he never got round to using it due to ill health
what i would like to know is it is a 15 inch transom now i have been offered a ex R N L I outboard with which is 18 inch half way between long and short shaft would i have to lift the transom so that the engine sits right or would it be ok sitting 3 inchs to low extending the transom is not a problem to me
thanks in advance for any advice
p/s its a mariner 40 hp 2 stroke 2007 and the boat can that up to a 40 hp
|
Your correct the rnli did use an 18" shaft engine easy to check measure from the underside of the clamp bracket, where it would sit on the transom to the anti ventilation plate , the plate that runs directly above the prop longshaft will be anything from 20" to 22" short 15" to 17" then the rnli engine sits somewhere inbetween. Boat transom is also easy to check with a tape measure 20" is long 15" short but expect a little variation either way.
That said an 18" engine may run on a longshaft transom as lifting the engine is common to gain a little extra speed & 2" can often be satisfactory, you may suffer a little ventilation which may be partially overcome by using doel fins/hydrofoils.
Best idea is sit the engine on the transom vertically and take a rule along the line of the boat keel and note where the av plate is. It should be level or set slightly high. I normally start 1"up from level which is usually fine.
spy-sea-one
