Transom Plates

[NTGeorge]

Hi all

Quick question on transom plates for those that might know, why do shops fit transom plates to alloy boats?
I understand the reasons for putting it onto glass boats, and can hazard a guess as it's to prevent the box'd section of alluminium from crushing. Is there any other reason. Is it a standard?
I ask as I have a fabrication workshop and I'm starting to branch off and make alloy plate boats, and it's just about time to bolt the engine onto the first project.
Can I ulternativly just weld in crush tubes for the top bolts, the bottom two just bolt to plate.

Cheers

[gonzo]

It depends on the structural design.

[daiquiri]

Because it costs less to replace a worn out or corroded transom plate than to repair or replace a corroded transom.
Each time you tighten the clamp screw to the transom plate, you bite into the underneath metal. After removing the outboard you leave behind a small exposed area ready to be attacked by corrosion. The corrosion will slowly work its way even without removing the motor, if clamps and the supporting plate (be it the transom or the transom plate) are made of incompatible metals (like steel and aluminum) and the sea water is nearby.

[NTGeorge]

So it's more of a sacrificial material. Is there a min. thickness or do people just throw in the 6mm plates because that is the done thing. I have alot of 4mm plate from the build and don't see it adding the the structural integrity of the hull, so if I can get away with 4mm that would be great.
Thanks for your responce.

I'll try an attacha pic of the boatfor you guys, this was taken a fair while ago.