Jack plate on SST transom?

johnbottsr

Petty Officer 2nd Class
Joined
Oct 6, 2012
Messages
104
I have an early '90s Phantom 216 SST and the outboard appears two be mounted too low (cavitation plate runs a couple of inches below the water at WOT.
I am a novice to boats and was told this by my friend who has been around them a long time.
He made this assessment after riding in the boat and noticing a large amout of spray coming from the lower unit and seeing where the cav plate was in relation to the water.

Now, my dumb noob question is: Are the SST (space saving transom) designs good for a jack plate?
I would most likely get a manual hi-jacker to set the outboard height (there is no more adjustment up with the current rigging).

I just do not want to do more harm than good.

Thanks.
 

TheHookUp

Cadet
Joined
Feb 4, 2013
Messages
10
Re: Jack plate on SST transom?

Awesome boat! I have a 1994 196 Phantom sst and have been wondering the same thing. Getting a new outboard installed and have been reading about proper motor height, seemingly what your friend is observising is true. In that performance is ideal when the antiventilation plate is just at or below the water level. My research suggests that the jack plate will work on the sst transom however, the adjustments will effect your current rpms etc. Do you know your rpms and speed at WOT (wide open throttle)?
 

johnbottsr

Petty Officer 2nd Class
Joined
Oct 6, 2012
Messages
104
Re: Jack plate on SST transom?

Awesome boat! I have a 1994 196 Phantom sst and have been wondering the same thing. Getting a new outboard installed and have been reading about proper motor height, seemingly what your friend is observising is true. In that performance is ideal when the antiventilation plate is just at or below the water level. My research suggests that the jack plate will work on the sst transom however, the adjustments will effect your current rpms etc. Do you know your rpms and speed at WOT (wide open throttle)?

Unfortunately, I do not know my RPMs.
The boat was repowered with a Force 150HP and no tach.
After reading here I fret about saturated foam and want to rebuild the thing.
I do like the boat a lot because that 8' beam is so stable.

I should be installing a Lowrance Elite5 DSI sonar here soon and should have a good reading on top speed via GPS.
Current speedo reads about 38 MPH wide open but not sure I trust it.
 

TheHookUp

Cadet
Joined
Feb 4, 2013
Messages
10
Re: Jack plate on SST transom?

Unfortunately, I do not know my RPMs.
The boat was repowered with a Force 150HP and no tach.
After reading here I fret about saturated foam and want to rebuild the thing.
I do like the boat a lot because that 8' beam is so stable.

I should be installing a Lowrance Elite5 DSI sonar here soon and should have a good reading on top speed via GPS.
Current speedo reads about 38 MPH wide open but not sure I trust it.

Was talking with someone yesterday who recommended the jack plate for fine tuning but he mentioned that you also may have to replace your steering cables as the jack plate moves the motor back about 5 inches. Not sure about that.
If 38 is accurate than that does sound low unless your hull is filled with ice:blue:.
I am concerned about my boat being saturated as well although not sure how to find our without ripping all the foam out. I am repowering my boat in the next week or so and am currently painting it. While I was stripping it down I did pull up one of the floor board that was soft to reinforce it and noticed there was ice in the hole in the foam directly under the hole for the seat post. I hope thats not the case with the whole boat, thinking now that I should weigh it before putting the new motor on and check to see how close to dry weight plus trailer it is?hmmm. If you pull the plug in the summer and park the boat on a hill so everything will run out wouldnt all the ice(water) drain out anyway? Trying to justify not tearing up my floor and delaying my striper fishing season any further.
I am also looking at Lowrances but with a new motor and then the paint expense that will likely be next year.
 

johnbottsr

Petty Officer 2nd Class
Joined
Oct 6, 2012
Messages
104
Re: Jack plate on SST transom?

From what I have read on this fine forum, the steering cables can be a concern especially if you have hydraulic steering. I am led to think that straight mechanical steering is less of a problem (more cable slack?).
The jack plates come in varying offsets based on my research and 4" is about minimum AFAIK.

Also, I believe the way to see if your foam is saturated would be to take a cork boring tool and cut out a plug to see how it is down deep (build a relationship with your boat). There are a lot of threads discussing foam and the various degrees of "closed cell". It is a lot to take in. I have read the foam will retain water after exposure to saturation and is a concern.

Painting aluminum seems to be a tricky proposition for a layman like myself. I hope it goes good for you.

No stripers out here in WA. and I am jealous.
 

rndn

Commander
Joined
May 20, 2007
Messages
2,323
Re: Jack plate on SST transom?

I've had my 96 Phantom 2160 SST for several years and have not had any issues with the mounting height of the outboard. It's a 130 and powers the boat as well as handles very well. What exactly do you think you'll gain by adding a jack plate?
 

johnbottsr

Petty Officer 2nd Class
Joined
Oct 6, 2012
Messages
104
Re: Jack plate on SST transom?

I've had my 96 Phantom 2160 SST for several years and have not had any issues with the mounting height of the outboard. It's a 130 and powers the boat as well as handles very well. What exactly do you think you'll gain by adding a jack plate?

I'll take some pictures here in a little while and show you what I am looking at.
My concern is the motor rides too low in the water (cavitation plate is an inch or two below the surface at speed) and there is no more adjustment on the engine mount.

Sorry for not replying sooner, been caught up in outboard repairland.
 
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