why you shouldn't make a transom out of 2x4s

[zaroba]

i guess this could go here since it has to do with making boat parts.
hopefully it will help prevent anybody from trying to make a transom out of 2x4s

i just finished making a stand for my outboard so i could move it around easily with it off the boat. I made it out of 4x4s with a 2x4 on top to clamp the motor to. i took it out the the motor which was laying in the grass, clamped it, and stood it up. the top 2x4 promptly started to crack and the only thing that kept it from falling completely was the fact that it came to rest on the prop on one of the legs of the stand.

and to think that i was considering making a transom out of 2x4s

 

[joed]

Re: why you shouldn't make a transom out of 2x4s

It would have been fine if you had screwed or carriage bolted the 2x4 to the front of the 4x4x instead using those angle brackets.

 

[brents]

Re: why you shouldn't make a transom out of 2x4s

Seriusly, you built that thing way wrong. Ditch the angle brackets. I made one out of 2x4's alone and it held up just fine. So does the title of your thread suggest you think plywood is stronger than a 2x4?

 

[mthieme]

Re: why you shouldn't make a transom out of 2x4s

Even better...listen to this one...
One of my neighbors decides he's going to rent of his slips for a little extra cash. A guy with an 18' pontoon shows up.
About two weeks later I notice the motor hanging off the back mostly in the drink being suspended only by the cables. Evidently, there was a 2x6 laying on it's flat side across the tubes in the back which the motor was "mounted" to. When I say laying, I mean laying...absolutely nothing securing it. He put in reverse and off went the motor.

 

[zaroba]

Re: why you shouldn't make a transom out of 2x4s

yea, i realized i made it wrong after it broke and already have it fixed and holding the engine. instead of the single 2x4 on top, it now has 3 2x4s on the front of the 4x4s so the whole clamp is being supported, along with some 2x4s at a 45 degree angle on the base to add support between the 4x4s. i'm figuring the engines ability to twist the 2x4 is the reason it broke.



as for the 2x4 vs plywood strength question,
as i understand it, when comparing wood the same thickness, plywood is actually stronger due to the crossing grains. notice how the 2x4 split along the grain?
probably why transoms are made out of plywood instead of one huge single piece of wood.

 

[fishrdan]

Re: why you shouldn't make a transom out of 2x4s

He put in reverse and off went the motor.

I don't care where you're from, that right there is funny

 

[NelsonQ]

Re: why you shouldn't make a transom out of 2x4s

Evidently, there was a 2x6 laying on it's flat side across the tubes in the back which the motor was "mounted" to. When I say laying, I mean laying...absolutely nothing securing it. He put in reverse and off went the motor.

Wow. Did he not think that this engine which produces enough torque to drive his boat across the water needed to be fastened to the boat?

That's one special person. I'd give anything to have a video of him dropping the motor in the drink.

 

[i386]

Re: why you shouldn't make a transom out of 2x4s

I notched out my upright supports like this. There's very little stress put on fasteners this way.

 

[linkster01]

Re: why you shouldn't make a transom out of 2x4s

Yep, that's why more stick built commercial buildings are using engineered lumber, like plywood 2x4s instead of the old pine stuff. Its not mainstream yet but a few high buck government jobs I have been on used the stuff for any bearing walls over 12 feet.

 

[skargo]

Re: why you shouldn't make a transom out of 2x4s

Yep, that's why more stick built commercial buildings are using engineered lumber, like plywood 2x4s instead of the old pine stuff. Its not mainstream yet but a few high buck government jobs I have been on used the stuff for any bearing walls over 12 feet.

We built our house 2 years ago using engineered stuff, I was doubtful when I first looked at it, but it's strong!

Here's a pic of the floor joists.

We also uses Superior Walls(precast 5Kpsi concrete, which could be considered engineered I suppose. I love the built in studs too.

 

[jonesg]

Re: why you shouldn't make a transom out of 2x4s

Huh, wooden I beams.
As long as the "fallaparticle" board doesn't get wet.
It would be better with aviation style verticle grained sheer webbing though,
and cost more to boot.

 

[jonesg]

Re: why you shouldn't make a transom out of 2x4s

i guess this could go here since it has to do with making boat parts.
hopefully it will help prevent anybody from trying to make a transom out of 2x4s

i just finished making a stand for my outboard so i could move it around easily with it off the boat. I made it out of 4x4s with a 2x4 on top to clamp the motor to. i took it out the the motor which was laying in the grass, clamped it, and stood it up. the top 2x4 promptly started to crack and the only thing that kept it from falling completely was the fact that it came to rest on the prop on one of the legs of the stand.

and to think that i was considering making a transom out of 2x4s

The problem isn't the 2x4, or even the flimsy looking angle brackets.

Problem is engine 'earin,
its the unsupported lower part of the outboard mounting flange which allowed the engine to rotate backward and split the 2x4.
My V6 is mounted on a verticle 2x8 bolted to an auto engine stand, only the top 2 bolts are used .

 

[skargo]

Re: why you shouldn't make a transom out of 2x4s

Huh, wooden I beams.
As long as the "fallaparticle" board doesn't get wet.
It would be better with aviation style verticle grained sheer webbing though,
and cost more to boot.

I was just putting up an example of engineered product. Good thing it doesn't rain in my basement huh?
It's also oriented strand lumber, not "fallaparticle" board.

 

[jonesg]

Re: why you shouldn't make a transom out of 2x4s

You need more tools and 'stuff ',
an empty basement is a terrible thing.

 

[mthieme]

Re: why you shouldn't make a transom out of 2x4s

I notched out my upright supports like this. There's very little stress put on fasteners this way.

Excellent idea. I built two stands this summer...wish I thought of this.

 

[skargo]

Re: why you shouldn't make a transom out of 2x4s

You need more tools and 'stuff ',
an empty basement is a terrible thing.

That was when we built it, it's pretty full now. I keep my tools in my shop/garage.

I need to build a stand capable of holding a 73' Johnson 115, any tips?

 

[mthieme]

Re: why you shouldn't make a transom out of 2x4s

I like i386's design.
You're talking >300# of motor there...gotta welder in that thar shop?

 

[skargo]

Re: why you shouldn't make a transom out of 2x4s

I like i386's design.
You're talking >300# of motor there...gotta welder in that thar shop?

Yep, got any plans?

 

[new_boater]

Re: why you shouldn't make a transom out of 2x4s

here are several options that might help
http://forums.iboats.com/showthread.php?t=9704

also someone had posted a really nice drafting design plan not long ago.
i will see if i can find it

here it is .... done by dh4winn79

http://forums.iboats.com/showthread.php?t=266008&highlight=design+stand

hope it helps

 

[i386]

Re: why you shouldn't make a transom out of 2x4s

Here's a few more pics of mine...

I'm not sure the design would scale well to large engines though. I believe this one would be fine up to about 75HP. I'm planning on putting some wheels on it. The idea for the "arm" for servicing the L/U came from one of my engine shop manuals.

There have been several threads on engine stands over the years. I made mine similar to another one posted here.