I have to agree with Jake on this one - 5HP at sea with Kids….hmmm…..I had a similar dilemma partly because I had no idea how powerful a 5HP or 20HP was at the time. I obtained a reasonable idea from You Tube vids and by reading this forum.
5HP or even 10HP is limited to very near shore fishing in sheltered coastal areas or going on lakes and rivers – after a while the natural tendency is the need to expand ones horizons and wishing - oh I wish I could go that extra distance to that great beach I saw.
My personal opinion – Honwave IE 3.8/ 20HP all the way – good size for a small family, stable and powerful enough for the tides along this stretch of coast (in sensible weather that is) and superbly economical. I average 30 – 40 miles a trip on my boat and it costs around a tenner a trip. Big enough for 4 adults and can be handled by one – just - without a trailer that is.
To give you an idea of what it can do - a couple of weeks ago I went from Poole baiter/ Studland/ Old Harry/Swanage all the way to kimmeridge and back then across to Bournemouth Pier – all in a few hours with lots of lazing around at potter speed. I have been around the Isle of Wight Needles several times in it no problem – from Hamble to Ryde/ Portsmouth – it handles the tides no problem.
Next week I am off camping in Pembrookshire and will be taking the boat to Ramsay/ Skomer islands, next year I am planning on towing the boat through Europe down to the Croatian Coastline. I met a guy the other day who toured the Greek Islands in the same set up as mine! All I can say is the Honwave 3.8 is an incredibly flexible/ small economical SIB. My whole setup cost about £4000 – Boat/ Engine/ Trailer/ VHF/ Life Jackets/ Flares/ Air Horn/ Fenders/ Seat bags – worth every single penny I spent on it with the many hours of boating pleasure it has returned.
I met a guy down at Poole Baiter – 15 foot Power Boat/ 100HP Mercury – 20K setup at least. He told me that he rarely uses it because it costs too much in fuel….what’s the point in having a boat…meanwhile I am out on mine every second weekend at least (weather depending) for a fraction of the cost.
I originally started out with the idea like most people - folding it each time and packing in the camping trailer until I discovered that whole exercise was a complete pain in the arse. The last thing anyone wants at the end of a long day is deflating wet boats filled with clinging weed and sand.
Look on Ebay or go to Extreme Marine online and purchase yourself a jet ski/ Air Floor trailer for a couple of hundred smackers. The enjoyment factor goes up 10 fold and you save on your back as well. As I live 5 minutes from my launch I keep the engine on the boat and I have driven from Southampton – Poole towing it on the boat (a bit of a risk for the transom but if one drives slowly it is ok)
Hope this helps