propeller choice

[kieronriley]

Hi I have a 18 foot Shetland, it has a Johnson three cylinder70 h/p vro engine with a 13 3/4 x 15 propeller if I am on my own it will go on the plane but no matter how I try two up or any more and it wont go up, the prop is very very close to the cavitation plate, does anyone have a similar boat that can give me some advice, I am thinking I should go for a smaller diameter prop ? any help . Thanks. Kieron

 

[Mike k]

what about contacting these guys they are just up the road in Oldham http://www.crowthermarine.co.uk/

 

[Bouba]

Shetland boats don't allow anyone to sit up front. On a small planing boat it's essential to get the weight up front. You can do this by ballasting the bow, e.g. bottles of water and by putting a dolphin fin on the outboard

 

[BruceK]

These work a treat for getting out the hole quickly and being able to plane at lower speeds : http://nauticusinc.com/

However, the first thing I'd do is take your boat and trailer to a weigh bridge and make sure it's the correct weight and if not check any foam filled chambers for water retention.

 

[QBhoy]

Hi

Plus 1 on checking it's not saturated with water. Also check engine compression. Something is defo not right. That boat/engine/prop combo should have no bother planing and achieving close to 30mph.
Friend had a family 4 with a merc 60 and 15" prop. Would plane no bother with 3 adults without fwd weight distribution.

 

[QBhoy]

Although I should add, that perhaps 13" diameter is a bit much...pretty sure the above mentioned had an 11x15" or there abouts

 

[gordmac]

Will it reach maximum revs when you are on your own?