Before Berkeley kitted it, Struck's Sea Cat was published as a construction article in August, 1954, Model Airplane News, starting on p. 20. Two pages are the plans, at 1/4 size, and include all the ribs & formers, which the kit plans probably didn't include. Check with MAN to see if they have the plans available.

Berkeley's kits were considered by many to be very expensive plans because, while the plans were great, the wood quality was poor and the die-crunching inaccurate. Even if you traced the kit's parts on good wood, they probably wouldn't fit. If I were to build the Sea Cat, I'd do it from the MAN plans. Besides, a Berkeley kit is a token of a great period in modeling and I'd hate to see one lost when there's no need.

Just my opinion.
-Dave