Why a reverse stern

[davidpm]

A friend just bought this boat:
1983 Morgan Nelson Marek 364 Sail Boat For Sale - www.yachtworld.com

What is the the advantage of this stern.
Other than looks it don't seem to help anything and the looks don't thrill me so I'm just asking.

Is it my imagination or do Morgans usually go cheaper than other boats? What is the reason for that?

[Faster]

To some extent I suppose it's a 'racy' look, but I believe the rationale was to maximize heeled water line with the flat counter, yet minimize weight at the end of the boat at the same time. The look caught on and a lot of production boats went along for the ride, much the way everyone now has open/walkthru transoms.

Some would say it's a way to turn a 40 footer into a 35, or a way to pay 40 foot moorage rates for a 35 footer

I kind of do like the look, our last boat was similar, but not so extreme (though the photo may be exaggerating the situation) It does complicate the design of a decent stern ladder.

[davidpm]

I found this answer but if someone could elaborate I would appreciate it. what is L for example.

Paul B
09-25-2009, 01:25 PM
The reverse transom was an attempt to make fairly competitive boat more so, by eliminating weight in the stern.

The long sloping "reverse transom" sterns on IOR boats were done not to reduce weight, they were done to move the aft measurement point of "L" forward, reducing the measured length and hence the rating.
Paul Kotzebue
09-25-2009, 05:06 PM
The reverse transom was an attempt to make fairly competitive boat more so, by eliminating weight in the stern.

That is the effect. The cause is in the applicable rating rule.

The boat wasn't too long for it's rule then chopped, it was just a top 5 boat that wanted to be a head of the fleet boat. I'm pretty sure it was Ted Brewer that did it and they literally used a chainsaw the night after a race and competed the following day with better results. The idea caught on and has been used ever since. It think this was in the very early 1960's.

I know the 12 meter Columbia had a reverse transom in 1958, and I'm pretty sure Ted Brewer was not involved in that design. I believe the 12 meter rule doesn't measure anything aft of a waterline located 180 mm above the flotation waterline, so it makes sense to get rid of anything in the back of the boat that does not contribute to sailing length. The 12 meters used in the 1987 America's Cup looked like the reverse transoms went all the way forward to the aft measurement station.

Paul B is right about the IOR reverse transoms. The designer could locate the optimum position to measure the aft end of "L" with the transom corner.

[Faster]

Bob Perry... service call on Aisle 3!! Pending someone's corrections, I think.....

"L" is the 'measured length' under the rule, and was the distance between the fore and aft girth measurements.. girth measurements were taken from deck edge to deck edge. So the reverse transom moved the aft girth point forward, shortening the measured 'L' vis a vis the boat's actual length for a rating advantage.

Surprisingly little available on IOR on a google search.. I know I have a graphic at home with a drawing of the pertinent IOR measurement points somewhere, but it's not on the web as far as I can see...

[jameso]

reverse transom looks (in my eyes) far better than a open, or swim platform stern.

[chef2sail]

We have a slight reverse transom...I like the looks of it better also...i thought it was a functionality of long water line without the weight, but that is just the musing s of my ameteur mind

Dave

[norsearayder]

i also thought that a reverse stern was for increasing water line ,thereby increasing speed .it may also increse bouyancy in a following sea and also added space for storage

[tommays]

I am sure Bob P could tell you better BUT everything was done to try and make the boat faster within getting a penalty form the silly rule of the time

[davidpm]

Originally Posted by norsearayder

i also thought that a reverse stern was for increasing water line ,thereby increasing speed .it may also increse bouyancy in a following sea and also added space for storage

Several folks have sugested this. But since the cost of extending the deck is minimal since you are already paying for the hull it does not make sense.