Motor Shaft Length

swstandring · #1 10-25-2002, 08:18 PM

Question for all of you who own a mid-70's 20 foot Seacraft Classic. When looking to repower, what shaft length motor would be the correct size? I have been told that a 23" shaft is needed and I do not know of anyone who currently makes motors with that length. Will a rebuilt transom be needed in order to repower?

Mark · #2 10-26-2002, 10:58 AM

I have a 1971 20CC with a 20" shaft Yamaha that pushes the boat rather nicely. I also have a 1976 18CC with a 20" engine shaft which also works well.

ScottM · #3 10-28-2002, 01:56 AM

swstandring,
No such thing as a 23" shaft length. Sounds like you should be using a 25".

Scott

Rich · #4 10-28-2002, 10:39 AM

Engine shaft lengths:

20"
25"
30"

I think the 20' SC's typically had 20" transom cuts, and the 23' had a 25". If you look through some of the transom rebuilds you will see that some guys have decided to move up. For instance FELLOW-SHIP went from a 25" up to a 30" when he rebuilt his Transom. I did the same on my 23'.

Hammer went from a 20" on his 20' to a 25".

http://www.classicseacraft.com/hammers20CCpage2.htm

So to answer the question, if the Transom hasn't been modified you will probably need a 20" shaft motor.

[ October 28, 2002, 09:41 AM: Message edited by: Rich ]

Roland Rodriguez · #5 10-31-2002, 07:31 PM

If your transom is in good shape and set for a 20 inch motor, an inexpensive alternative would be an aluminum jack plate. The hydraulic version is price'y but real nice. Byusing this method you could utilize the more common 25 inch shafts. Just a thought!

[ October 31, 2002, 06:32 PM: Message edited by: Roland Rodriguez ]

johnnie q · #6 12-10-2002, 05:08 PM

have heard older guys call them sinkcraft.because the 20" transom .I own a 71 20' and restored 4 years ago and replaced my transom with a 25" and it works fine.