Draggin' tail

evilwind1

Petty Officer 3rd Class
Joined
Jun 6, 2006
Messages
92
Hi, Having a hard time with adjusting jack plate. I have a 1969 17' Wellcraft runabout style. I put a 115hp Johnson 25" shaft and a Bob's manual w/ 5" setback.I've been told to raise cav. plate height 1" to 12" of setback so I estimated 1/2" raise for the 5" setback. I think the boat may be too short for a jack plate. When I take off it seems like the prop really digs in and bogs, spraying water up and shooting onto engine. When I slow down the stern goes down and the water rushes up,like you slammed on brakes. I am now in the process of raising the transom height and I will mount the motor right to it. Do you think a hydro-fin and/or self adjust tabs are good. The boat had an 85 Merc and is pretty heavy so I don't think the 115 is too much. Also what prop would be better,,17 or 19, I'm looking for more top end. BTW this is about the fifth boat I have owned/tinkered with this year but I am really impressed with the ride of this oldie( once it gets up on plane!) Anyway, thanks for the help.
 

1730V

Chief Petty Officer
Joined
Feb 14, 2004
Messages
563
Re: Draggin' tail

The cav. plate should be about 1" above the lowest part of the hull, as a starting point. The jack plate allows you more height because of the set back.

The self adjusting trim tabs are wonderful. I would not add a fin.

You need a tachometer to choose the right prop. That engine needs to be able to turn at least 5500, with a light load.
 
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