Max Engine Ratings

ed_dash · 01 October 2010, 17:47

I have been looking at a new rib, out of curiousity mainly but have noticed that the max engine sizes have reduced. Is this due to 4 strokes being heavier?

Eg. My current BWM deepsea 18, not widely known as a good boat but can have a max engine of 150 single or twin 70's. A similar sized Humber OP can have a 115 single or twin 40's, Ribcraft 5.3 is 100 single.

Is it purely down to engine weight or have the rules become more stringent, surely the boats are stronger and better made now than they were when mine was made 10yrs ago.

BogMonster · 01 October 2010, 23:41

I don't know the answer but I would think another element to consider is the increasingly litigation conscious world we live in and the possibility that some numpty will stick the maximum rated engine on their boat and then sue somebody because it chine walks at full moo, chucks them out and then runs them over because they didn't bother with the kill cord because it was "only in the bay and it's calm". So to reduce the liability, reduce the HP and you will reduce the idiot factor.

My old Humber Destroyer was rated to 150hp on the plate but I think the same boat made now is only rated to about 130.

Pikey Dave · 02 October 2010, 09:49

Strangely enough I noticed on the Ribcraft website the other day that my 6.4 is now only rated to 225hp where mine is plated at 225kw which is about 300hp. I have 2x115hp so in theory I'm over the current max rating, unless there's a typo on the website.

HUMBER P4VWL · 02 October 2010, 21:51

Im sure theres a member on her that is adamant the SR5.4 used to be rated to 115 not 90. He'll be along soon no doubt

Cant remember if im making this up but if two boats have the same length, but one has a wider beam it can take a bigger engine. Might be talking rubbish.

Obviously the transom strength must have a lot to do with it, as will dispacement I suppose. A deep V heavier hull surely would take more than some shallow V lightweight plastic thing.