im a total newbie

[oldgit]

IMHO a speedboat is the last vessel to buy to go fishing with they are designed to be on the move.
A pretty awful platform to fish from at anchor with no freeboard to speak off.

 

[Hugh Foulis]

To put some things into perspective, there was a boat auction at a local auctioneers a couple of weeks ago. I went to view and there was a 13' dory on a Snipe trailer with a 25hp o/b. The hull was probably usable straight off the trailer but if it was me I would want to give the engine a complete service, clean the carb thoroughly, fill with fresh mixture and check that it started before going near water.
I heard that it sold for £800 and in my opinion wanted another £200 + spent on it. It would make a great boat for lake fishing, it would make a great boat for having fun in an estuary or bay but I am not convinced I would want to sit on it fishing at sea in anything much above a flat calm.
I suspect the OP needs to be looking at buying an outfit like that if that is what he wants and for about £1k has something usable. Buying what he has described will still lead to a similar outlay and very possibly more to get to the same position plus the time and work he will need to put into it.