motor shim/wedge plate?

[toey1977]

Well not really sure what to call this thread or if it is even in the right section, but was wondering if the plate (don't know what else to call it) needs to be wedged like mine on the boat I am restoring. I have never seen it done before the boat is 17ft ski boat with 110 liter in bow fuel tank and does have a rear mounted ski pole, was more curious if it would really need this to help with extra trim, the motor is 140hp Evinrude. As I am fixing up the boat I will be replacing this with a bit of sealed marine ply but didn't want to have to wedge it like this every other boat I have taken notice of just has a flat base plate. So I'am after the thoughts of the brains on this site as to why or if it needs to be redone. My though was the boat manufacture would make a transom square and the motor manufacture would have all the adjustment needed in the setup of the motor.

 

[gm280]

toey1977, usually when someone installed such an angled plate is to allow the engine to tuck under at more or an angle to get it to plane out. But if you can plane now with the engine at it's present tilt, I see no reason for that plate myself. But that is just my opinion and not being there to see how the engine planes the hull.

 

[jbcurt00]

Title changed

Thats a tapered shim/wedge

Used to make slight changes in the trim angle of the motor. As a manual trimmotor, you only have 6 trim settings using the tilt pin (silver lever pointing down in the bottom center of the pix) and the 6holes it can be put thru. W the shim, you get a 1/2 trim setting, or should assuming the shim is sized correctly.

Could also have been used to force the bow down, possibly from running an oversized motor.

What 17ft ski boat?

 

[toey1977]

Never had this boat out on the water so don't know how it planes also it has power tilt and trim the boat is rated to have a 150hp motor and it is running a 85 Evinrude 140 the boat is a Caribbean Jaguar. the angle the motor is on now is just where i left it as i am getting ready to take it off the boat. They are / were apparently a well designed Australian made boat, think they ran the same design from the late 70's to the early 90's, I have pics of the boat as i bought it in my rebuild thread.

 

[toey1977]

I have been googling the boat looking for pictures of the transoms, I have so far found 5 different pictures of the same model all with ski poles all ranging 115 to 150 hp motors and one with a 140 evinrude no other boats the same model seem to have the wedged shim plate on them a couple didn't even have a plate just straight bolted to the transom so I may just replace the plate with a flat piece of marine ply and when launch day comes around see how she goes

 

[Sea Rider]

My though was the boat manufacture would make a transom square and the motor manufacture would have all the adjustment needed in the setup of the motor.]

Boats manufactirers and OB's manufactures have their own height parameters, doesn't mean a thing that both will match at the Tip Top height spot for both to work spotless. It's not as buying a tire and installing it to a tire rim. The concept t's well explained in :

http://forums.iboats.com/forum/gener...ths-mismatches

Happy Boating

 

[toey1977]

Boats manufactirers and OB's manufactures have their own height parameters, doesn't mean a thing that both will match at the Tip Top height spot for both to work spotless. It's not as buying a tire and installing it to a tire rim. The concept t's well explained in :

http://forums.iboats.com/forum/gener...ths-mismatches

Happy Boating

I have gone and read that and see what you were trying to say but that,s not what I was really asking about the o/b height and nor do think all transoms were the same, what I am trying to ask is there a reason my plate is wedged to give extra downwards trim, I have never seen it before on a boat and after googling I have yet to see it on a boat the same model as mine. surely what is a highly reguarded boat manufacture here in Australia would;nt make a transom so far out the the boat porposes so bad that it needs the extra trim. so I was just asking basically is it because someone wanted greater adjustment or is it commonly done, I know that the only true way to answer this question is to get it in the water but that is'nt really a option atm. I have even see the same model with twin batterys and two rear removable fuel tanks in the back but yet that boat was still running a yamaha 115 flat to the transom. I will be painting my new plate to match the boat so was just a check rather thank seal it to the transom and paint it to have to redo it again will be a pitta.

Thanks for the link it was appreciated

 

[toey1977]

Title changed

Thats a tapered shim/wedge

Used to make slight changes in the trim angle of the motor. As a manual trimmotor, you only have 6 trim settings using the tilt pin (silver lever pointing down in the bottom center of the pix) and the 6holes it can be put thru. W the shim, you get a 1/2 trim setting, or should assuming the shim is sized correctly.

Could also have been used to force the bow down, possibly from running an oversized motor.

What 17ft ski boat?

starting to think that being a older boat maybe the original motor did'nt have power tilt and trim and that's why it is there, well hoping anyway

 

[gm280]

With power tilt and trim, I really don't see a need unless there is something about the hull we are not privy to. :noidea: