A couple of things...
At one time Mr. Moesly once said, a bigger boat will normally ride better than a small boat.
The 25 was designed after the 21, so there should be some improvements build in.
Really the 21 was designed to go racing, and punching through head seas was important and getting wet was not.
The other thing I noticed from the pictures and I think Sandy and Denny can attest to it...Blue Heron and I think Connor are always standing up when they are punching thru the waves. On the 21 when I was driving and when Sandy was driving we never felt the need to stand.
Last of all this information below comes from a guy who has tested the 25 and 21 very throughly.
Quote:
Cleaning up my home messages and wasn't sure if I answered you. The boat is up and running and we have ventilation problems with the outboards that Jamie positioned somewhat between the keel and mid hull panels. Next week we're modifying the outboard bracket to move the engines furthr apart like I've seen on some of the old photos. We think if we clear the riser between the keel and mid hull panels we will see cleaner water. To counter the weight of the Armstrong bracket and twin Suzuki 140s, we've had to put 500 pounds of chain in the bow to get her to balance right. She runs great in a head sea, plunges a little too much to my liking in a following sea. Overall, very good forebody but not as good as the SeaCraft 25'. It probably could use more flare in the bow and a big spray rail forward between the chine and keel. What realy surprised me is how softly she landed when launching off 3' foot chop on top of 4' long swells. Considering the average deadrise is about 20 degrees compared to the 26 degrees of the SeaCraft 25', she is almost as soft!
The 21' is quite impressive and with the mods we've made to the 25', including a production 30' based on a geosim of it, it is obvious Moesly was a great designer. We are working on a high seakeeping 24-26' RIB with high displacement of ~ 8500 lbs. Based on our tests on the 25', she simply tops out at a displacement of 7500 lbs so it does not make a good parent craft. I was thinking of stretching the 21' to about 24.5' and was curious about the differences between the 21' and the Potter 23'. I have limited experience from riding the 23' over 30 years ago and as best I remember it wasn't that impressed with the ride and remember getting soaked. I need to know more about the 23' to see if stretching the 21' will detract from her seakeeping.
We have used a digital camera and 3d software to create a very accurate solid model of the 21 and 25 and the differences/similarities are amazing. If you keep the keel panel of the 21' as the baseline parallel to the static waterline, the mid and outer panels slope down as they move aft, about 1.5" over 6'.
Anyway, didn't mean to go on so long BTW, the serial # of my 21' is 111.