Hi Tom
I wrote a post last year or later regarding the difference between the Mk 1 and 2 and 3 apart from the obvious ?
The mold for the Mk 2s and Mk 3s did have the deadwood scolloped out around the prop aperture? to allow more water around the prop. My father did the same when we built the battern mold for Jilpanger back in 1972 and it did help a little bit . Egret II only has a BMW 6hp in her and swings a large prop with large fan tip blades at the top to try and keep them biting as it spins. That was why I changed from a 2 blade to 3 blade on Porters advice to keep the blades from hiding behind the back of the keel ,which a 2 bladed does .Which means every time a 2 blade prop came out from behind the keel it would push the water away instead of biting the water and this caused the so called cavitation problem with 2 bladed props because the water never got a chance to fill the hole again .The disadvantages with a 3 bladed prop was the little loss of boat speed .
Regarding reversing? Egret II reverses like a mad cow !
Below are a few photo's of Jilpangers rudder area sorry about the quality
Cheers Bear