advice on outboard power for 17ft grp cabin cruiser

[fishermanjack]

Hi guys i have a 17ft grp cabin cruiser that i will be using on the river trent, i was just wondering what power outboard you guys would recommend, id need it to be powerful enough to take me against the flow of the river when there is extra water on the river, i was thinking 20bhp may be sufficient to get me out of trouble if i was stuck at a higher river level ( id never plan to be stuck but sometimes flash floods happen) thanks

[Bacchus]

It would probably help to know what sort of boat - hull design has an impact. A small planing boat like a Mayland or a Shetland would need 30-40hp to plane, but a small 10hp will struggle to push it meaningfully. A displacement hull would only need about 10hp to get up to max displacement, and any more horses you throw at it will just cost you money to make more noise and wash.

[Jen-in-Wellies]

19 hours ago, fishermanjack said:

get me out of trouble if i was stuck at a higher river level ( id never plan to be stuck but sometimes flash floods happen)

The Trent, that far down on the navigable sections, doesn't really get flash floods in the way rivers like the tributory Soar and Don get, that are only a short distance from their headwaters.. The Trent drains a large part of central England. It is slow to rise and slow to fall. Flooding is predictable, from the weather in the days ahead of it reaching the navigable stretches. When it does, you and your boat want to be somewhere else, or on a very secure floating mooring, as the result is biblical! 

Then there is the Aegir. Again, it is dramatic, but predictable. 

https://www.bbc.co.uk/news/uk-england-lincolnshire-67902247

[Momac]

10 hours ago, fishermanjack said:

Hi guys i have a 17ft grp cabin cruiser that i will be using on the river trent, i was just wondering what power outboard you guys would recommend, id need it to be powerful enough to take me against the flow of the river when there is extra water on the river, i was thinking 20bhp may be sufficient to get me out of trouble if i was stuck at a higher river level ( id never plan to be stuck but sometimes flash floods happen) thanks

This one has 20hp   . I am sure there are other examples with much greater power . A limiting factor may be the maximum power that the boat is rated to accept.