Originally Posted by Manos
When you say I want a 7 mtr RIB you mean a 7mtr total length (OVERALL) not hull length.
So tell me again what I am so wrong about?
No one is doubting that there are several ways to measure a boat. Only one of these is the length overall (LOA, shown in green below), which goes from the furthest projection forward, to the furthest projection aft. That's from the very front of the boat, to the very back, including (in a RIB) the tubes and the drives. In a sailing boat it includes the pulpit, bowsprit and anything else that is permanently part of the boat. LOA is the biggest possible length measurement for a boat. Any other measurement is not the LOA, it's something different.
Depending on the design of the boat, the LOA may be more or less the same as the hull length (or more technically the LBP that quinquarimarine referred to, which for a RIB would generally be from the transom to the point where the front of the hull meets the tubes, shown in yellow below). Take a rowing boat for example; it's just a hull so the LOA is the same as the hull length. A cruiser with a swim platform and one of those sticking out anchor beaks will have a LOA rather greater than the hull length. A RIB with tubes sticking out at both ends also has a longer LOA then the hull length. But you agree with that -- it's what I quoted above.
Then there's the waterline length LWL (shown in blue below) which may be the same as the hull length and the LOA (consider a dutch barge for example). A RIB has a raked bow so the LWL is less than the hull length which in turn is less than the LOA.
How the RYA or BIBOA choose to measure RIBs for race classification is not relevant to this debate. If their chosen measurement is less than the LOA, then it doesn't make it a different sort of LOA!
Generally speaking RIB model designations are based on LOA with a degree of artistic licence to make the boat sound a bit bigger than it really is. It would be interesting to compile a list of measurements of LOA, hull length and LWL for different RIBs -- anyone got a tape measure handy?