I have another answer, but on a very uncommon rib !
The rib is a Stingray-Tomcat (european name) 6.3 catamaran, with 2x50hp Tohatsu (carb version) and a pair of (too) long props (15" stainless for speed)
With 6 male adults on board, she was unable to plane on the starboard engine - but she did on the port one.
The top speed was 36knots with 2 on board, not bad at all.
The same boat run at 45 knots with a pair of 90 Yam (2 stroke) and 15" ali props @6000 rpm, a bit too high - 16 or 17" SS should gain 2 or 3 knots easily, possibly more.