Alu Angle instead of jackplate, anyone tried it?

[kimswang]

I am playing with a thought of using Angles instead of jackplates. First off I need a 10" lift. The idea is to mount two angles to each other where one is mounted to the boat and the other to the engine. I thought of using 3"x3"x1/2" Aluminum angle and wondered if it is too much overkill. This is not supposed to be a permanent solution but rather a tool to dial my engines in to a 100% optimum setting. I have all the alu to weld my bracket and make it permanent, but this will be done after I find the correct height. Any suggestions? The engines are OMC V8's...

[BarryStrawn]

If you draw it out I think you will find you need 4" legs on the 1/2" angles. The upper and lower bolts are 1.5" offset and you have to allow for the radius inside the angle and thickness of the overlapped angles.

[flabum1017]

I don't know...... 1/2" seems pretty flimsy for a v-8 especially 10" in the air.....................

[jphii]

That's all my bracket is is aluminum angle. You will need more than 3" x 3". 1/2" thick is more than enough.

[kimswang]

That's all my bracket is is aluminum angle. You will need more than 3" x 3". 1/2" thick is more than enough.

That is pretty much what I had in mind, with a few exceptions... I will bolt the angle to the boat outward instead of inward (should not make a bit difference..). Now, would you make that thing 2 feet long and bolt the motor to the top and bolt the bottom to the boat ? I'm thinking this way: there will be 4 plates of 1/2" thick and 3" long preventing this from breaking, more than what is used on a Boeing 767... This experiment will cost me a whopping $250,- for all three engines and it will able me to get my engines dialed in 100%.. I will later take my bracket off and have the backplate welded to the new specks.. It is just an idea I had, but after this picture I am more than convinced it will be strong enough.. Thanks a lot..

[kimswang]

Now, would you make that thing 2 feet long and bolt the motor to the top and bolt the bottom to the boat ?

[BarryStrawn]

May not be critical, but arranged like [ ] is stronger than ] [. Plus having the upper bolts closer to the corner is better.

How do you plan to dial it in. Are you going to slot them?

[kimswang]

May not be critical, but arranged like [ ] is stronger than ] [. Plus having the upper bolts closer to the corner is better.

How do you plan to dial it in. Are you going to slot them?

I plan to use american standard angle and it has rounded edges, hence the arrangement of making them outwards should make it stronger (more surface to surface area). I plan on using holes on a line instead of slots so that I can adjust up or down in 1" incraments. I thought of using 3/8" bolts for this (4 on each side) and regular 1/2" to fasten the motor as well as the bracket to the boat. When everything is dialed in I will then weld 1/2" thick alu plates with gussets and mount jackplates so that their most upward position will be right before I loose waterpressure. This should in theory be the ideal settings. The angle idea is just to make the initial adjustments and play around with different heights of the motors.

The setup from different factories with triple setup shows outer motors of 25" mids and a center motor with a 30" mid. This setup with a little bit stagger will give a max of 7" difference between the motors. If you set a motor 26-28" out from center on a 24 degree bottom there is however a difference of 10", hence my angles to play around and get a 100% correct setup. If a 10" difference between the motors is indeed needed, I will then make two 20" motors and a 30" center motor, different from what I have now of all being 25" mids.

I really do appreciate all and every input...

[BarryStrawn]

I plan to use american standard angle and it has rounded edges, hence the arrangement of making them outwards should make it stronger (more surface to surface area).

You are assembling a torque box. So arranged like [ ] makes it larger (stiffer) than ] [ while using same materials. The fillet on the inside of the angle works the same for either arrangement and I don't see how the radius on the edge of each leg makes any difference. The amount of overlap where you join the angles would seem to be the same either arrangement.

[kimswang]

Here is the idea looking from atop..



What do you think?

[BarryStrawn]

I now see why we were on different pages. But drilling all new mounting holes in the boat seems extreme to me.

The drawing does show the bolt spacing problems when trying to make a jackplate from 3" angle. Do you already have the 3" angle purchased?

[kimswang]

I now see why we were on different pages. But drilling all new mounting holes in the boat seems extreme to me.

The drawing does show the bolt spacing problems when trying to make a jackplate from 3" angle. Do you already have the 3" angle purchased?

No, I have to order it on and have considered the 3"x4" angle. You think 3/8" thicknes will do it? There is no problems drilling in the boat as that is an alubracket that will be welded anyway...

[BarryStrawn]

I would not use 3/8 angle.

[STV_Keith]

1/2 minimum Kim. Those V8's are heavy and are gonna lever a hole bunch being up that high!

[STV_Keith]

1/2 minimum Kim. Those V8's are heavy and are gonna lever a hole bunch being up that high!