Jackplates

mtduckhunter

Petty Officer 1st Class
Joined
Jan 31, 2008
Messages
241
What exactly does a jackplate do besides raise the motor height? i see different setbacks like 6" 8" 10" and 12".

im starting a bass boat project soon and i want to get the best perfomance out of it. would a jackplate be a good addition? if so what setback?

the boat is a 15 or 16 foot terry bass boat. about a late 70's model. im putting a 1978 johnson 70 hp on it. im not sure of the prop pitch because i cant find it (the pitch). i want to put a fast prop on it but not run high RPM's. im also not sure of the RPM's because i dont have a tach hooked up yet.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Jackplates

i had that vintage 14 foot terry bass, thought that was what was in your avatar. they are not speed boats , like the newer bass boats. they are long and narrow, be careful putting that much power on that boat. there is no need for a jack plate on it. but the right length shaft motor, and be good to go.
 

p man

Cadet
Joined
Sep 6, 2007
Messages
8
Re: Jackplates

set back can change the the running angle of your boat. It doesnt always mean more speed but in some applications it can decrease the wetted surface of your hull (ie less drag). Set back is also dependent on the amount of hp you plan to run. It can compensate for low hp motors so that the boat can effectivly carry more weight.
 

mtduckhunter

Petty Officer 1st Class
Joined
Jan 31, 2008
Messages
241
Re: Jackplates

the boat in my avatar is a monark and it has hook. im taking that motor and putting it on the terry. the terry is a bass boat, looks to be a faster hull than the monark. i just thought a jackplate would give me more speed.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Jackplates

adding the jack plate will also throw the weight balance on on that boat. as i said before they are not speed boats, they were designed for fishing, and can be a little unstable at high speeds because the are so narrow. but a great fishing boat.
 

mtduckhunter

Petty Officer 1st Class
Joined
Jan 31, 2008
Messages
241
Re: Jackplates

thanks guys! now i dont have to spend 400 bucks on that.
 

stevewolverton

Petty Officer 1st Class
Joined
Mar 30, 2008
Messages
262
Re: Jackplates

They raise the motor and place it further back. This is supposed to gain more speed by having less lower unit in the water (less drag) and it's supposed to be cleaner water behind the boat. :confused:

I'm using one so I could put a 20" shaft motor on a short shaft (15") transom. :D
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Jackplates

Run the boat without it first if you're unsure. When rigging the boat make sure to use a steering cable long enough that you can add one later if you choose to do so.

Once you get the boat rigged and set up the way you want (which may or may not be the same as someone else would distribute the weight) see how it reacts. If you need a lot of positive trim to carry the nose, then some offset will help. If the boat is a pad hull and has a step in the transom, most likely it would help.

With the ability to easily raise the motor you can take advantage of props with more technology. There are some nice 4 blade props in the range you'll be looking at.

Get it rigged and establish your baseline. Then you'll know for sure.
 

mtduckhunter

Petty Officer 1st Class
Joined
Jan 31, 2008
Messages
241
Re: Jackplates

now ive decided to put money into the boat i already have insted of buying another project boat.

the boat in my avatar, a 15 foot monark. the hull has hook, the transom needs to be replaced, and when under power the floor bulges up in the stern.

how (if any) would a jackplate help this boat?
 
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