Lengthened Ocean Alexander MK1 handling characteristics?

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Senior Member
Jul 30, 2008
Vessel Name
Southern Promise MMSI 258170360
Vessel Make
Ocean Alexander 55 Mk1
Anyone out there with experience with lengthened Ocean Alexander MK1?
I am looking at one that was lengthened by 3 4 ft. As far as I know the propellers and rudders were not moved back. *I guess this will influence how the boat behaves when maneuvering in tight quarters. *What will the effect of having a larger (doubled?) overhang aft of the propeller/rudder be?
BTW: What was the main reason these boats where lengthened? To counteract squatting at cruising speed? *Added cockpit space?
I have always heard the standard rule of thumb on extensions is you can lengthen up to 15% and get away without moving rudder, etc. You would fall far below that so I would imagine no problem. I think they were lengthened to copy the huge aft deck on the Flemings, you would also get more speed, load capacity, storage, better ride in head seas and improved fuel efficiency. The rudders on the OA are tad on the small side to me so I don't know if tracking would improve or not.
Unless the rudders and* vertical related components were increased in size, handling problems may result especially in a following sea. Tracking will likewise suffer. *Adding flotation aft is counter-intuitive unless a balancing weight is likewise added such as bait tanks, fuel storage or machinery. I've first hand experience with a 12% hull extension on a large yacht. It was better in the dock and much worse on the go. All the "best" boats have their rudders and props far back to begin with - look at all the Monk designed vessels OA and others have built during the past 30 years or more - including the MKI.
Many of the party boats that charter here in NYC have hugely extended hulls past the rudder post.

USCG admeasures charter boats from the bow to the rudder post , so with cheap help only having the tiny 100Ton tickets , the boats were specially built to be BIG , but measure small.

Ha , and you thought the racy rag baggers were the only folks out to fool the measuring tape!

Seems not to harm the operation of the boat as the river can run 5K , 4 times a day , and the charter party expects to walk the same dock to their cars.

A lengthened hull w rudders fwd could have a problem in following seas as the sea approaching from the stern would start pushing the stern into a broach before the rudders could offer help.

Eric Henning
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