PH 18 - Transom Stress Cracks - Minor I hope!

[Todd]

Cary B: Where is your launch going to be?

[ncsailors]

Outboards place a BIG strain on transoms. I wonder what
ever happened to "knee braces", those 45 degree highly
attached screwed-in reinforcements? I'm all for S&G,
glass cloth, and epoxy - but seems like in some areas
the tricks of the old framed-boat days, were useful.

An outboard, hanging off a transom in an exagerated way -
places a large magnified load on a thin plywood transom.
And then under power - all that pushing and twisting,
I'm all for over-design, over bracing.

elec engineer

[jacquesmm]

Outboards place a BIG strain on transoms. I wonder what
ever happened to "knee braces", those 45 degree highly
attached screwed-in reinforcements? I'm all for S&G,
glass cloth, and epoxy - but seems like in some areas
the tricks of the old framed-boat days, were useful.

They are still there, on all our plans but with other names.
On Monday, we will post a new HowTo with pictures and you'll see those "knee braces".

[caryb]

Thanks for all the replies.

This one goes into the "I should have known better department". I never really thought of the motor well as a structural member! It makes perfect sense now that I think about it but, after all the overbuilding I did on the transom it never occurred to me that I needed to strengthen the motor well.

I trailered the boat almost 700 miles and ran the motor almost 5 hours this weekend and the cracks did not worsen nor did any new ones appear.

Thanks again to Jacques for walking me through some last minute repairs that saved the weekend and the inaugural boat launch.

CaryB

[jacquesmm]

Good news: those two layers of tape inside the motorwell made all the difference.

The new HowTo about motorwells should be posted today.