Engine mounting height...( shaft length )

[stingraymax]

I have a 17ft Rib and I have a 99 Johnson 90hp long shaft engine.<br />Now the problem is that I need a 25 inch shaft for this boat.<br />What Can I do to mount the engine 5inches lower ? Are there brackets that let you lower your engine about 5 inches, or can I build something to mount it 5 inch lower or what should I do ?

 

[KCLOST]

Re: Engine mounting height...( shaft length )

I think some Jack Plates will help... Look for ones that have both travel options (up and down)... But you don't want to go so far down the you begin to submerge part of the powerhead

 

[stingraymax]

Re: Engine mounting height...( shaft length )

thanks, I think that I will have enough with 3 inch going down so I doubt that Will harm the engine.<br /><br />If somebody can help me to a link where they sell these up/down jacks, that would be very welcome I can only find the ones that lift up.<br /><br />Thanks

 

[AMD Rules]

Re: Engine mounting height...( shaft length )

Can't you just mount one of these upside down?<br /> Th Marine Fixed Jack Plate

 

[Solittle]

Re: Engine mounting height...( shaft length )

I know you are in Belgium and I have no clue on how boats built there differ from those here. I have never seen or heard of a 17' boat here with a 25" transom.

 

[stingraymax]

Re: Engine mounting height...( shaft length )

Well it is a 5.2M Narwhal they are actualy built in Spain and when I measure the top of the transom to the bottom of the boat it is 23inches so ... Don't ask me why I am new to this but that is what I measure...

 

[KCLOST]

Re: Engine mounting height...( shaft length )

Stingray,,,,<br /><br />Get the jack plate to mount the motor so you have some options, but you may be suprised at what you find.... You will most likely want the cavitation plate about 1-2" or more! above the very bottom of the hull for optimum performance...<br /><br />But I don't know what a Narwal is, so I may be full of S!##....

 

[stingraymax]

Re: Engine mounting height...( shaft length )

Thanks for the Help...<br />The boat is a RIB.

 

[Solittle]

Re: Engine mounting height...( shaft length )

Could you make a cutout for the transom? That would drop the motor down.

 

[pckkc]

Re: Engine mounting height...( shaft length )

Hey Stingray.I have a 15" shaft motor on a 20" transom. I dropped it about 3 1/2 inches with 4 pieces of angle iron and some 3/16 by 4" plate.All welded together.You should try to keep the cavatation plate about 1 1/2 to 2 inches above the keel .This worked perfectly for me but,I cant pick the motor up enough to lock it in the raised position.I'm just a little more careful launching and backing down the ramp.It sits plenty high on the trailer anyway. How are things in Belgium? I read the other day that Eddy Merckx and Lance Armstrong are pretty good friends.It's no wonder I guess. (Belgian Eddy Merckx -(The Cannibal)is the winningest bicyclist of all time-) Back to the origional subject,I didn't think that cutting the transom on my fiberglass boat was a good idea so I just figured how much drop I needed and started cutting and welding.Not a major problem anyway.I was a little concerned about the weight being pushed back another 8 inches(200 pounds) but,after 8 months of hard use not a problem. Good luck and safe sailing.

 

[stingraymax]

Re: Engine mounting height...( shaft length )

Thanks for the help, I already started looking into fabricating something myself