Engine to boat size

[Jack09]

Hi,

I'm looking to buy my first rib and it will need to accomodate 2-3 people but up to 5-6 if all the family decide to come out on a nice day. (2-3 adults and 2 children)

I'm looking at Ribs 3.8m+ , this will mainly be used for fishing but would be nice if I had the option of a bit of speed to pull my son on an inflatable.

Is there a general rule of thumb when it comes to engine HP as there are Ribs carrying a 50hp engine and then some with a 9.9hp?

Obviously there will be a power and weight difference but I suppose I'm asking would a 9.9hp engine be enough to push a 4m+ rib and a load of 5-6 people?

I'm not experienced to see the difference between various engine sizes.

If someone could advise or point me in the direction of a previous thread that would be apprsiteated
Thanks
Jack

[Fenlander]

If you are looking at alloy or GRP hull RIBS... as opposed to inflatable SIBS with alloy floor panels but a flexible bottom skin... then outside my experience but for up to 6 folks... you are going to need far more than 4m and loads of power for that to be comfortable and safe at sea.

A 9.9 driving any boat SIB or RIB will not give the ability to get on the plane 6-up... nor 4-up and with some craft not with more than 2-up.