Can't dry-launch with bunks. Sinks boat on ramp!

[Limecc]

[Matt]

What an embarassment.

[jwalker]

That why you need toobs...

[Matt]

Or common sense.

[Limecc]

Originally Posted by jwalker

That why you need toobs...

Or roller trailer
Or trailer maintenance

[beamishken]

Nothing to do with it being a bunked trailer the angle of approach to the water was too steep the boat would have sunk regardless of what trailer it was on. Just clueless numptys

[Limecc]

Originally Posted by beamishken

Nothing to do with it being a bunked trailer the angle of approach to the water was too steep the boat would have sunk regardless of what trailer it was on. Just clueless numptys

I mean if a roller trailer they could have launched it on wood in the car park.

Also after it sank they had to push it back and submerge the engine completely because it needed deeper water and wouldn't slide on the bunks.

[beamishken]

Originally Posted by Limecc

I mean if a roller trailer they could have launched it on wood in the car park.

Also after it sank they had to push it back and submerge the engine completely because it needed deeper water and wouldn't slide on the bunks.

If they'd had half a brain cell at the point they realised the stern of the boat was going to sink they could have aborted & pulled it back up the truck & thought again.
A set of wheel skates or even a decent trolley jack would have got the boat to the water hung on the origional tow vehicle. Probably lots of ways they could have avoided the outcome
What they did was plain stupid.

[jwalker]

What surprised me was how unstable it became with such a small amount of water on board.

[GuyC]

Originally Posted by jwalker

What surprised me was how unstable it became with such a small amount of water on board.

Your stability results partially from your waterplane area, which is if you take a slice through the boat on the waterline, it's the area of the hull that is contributing to stability that counts. The further away from the centreline, the more effect it has.

In this instance the immersion of the aft end meant that the main hull wasn't adding to the buoyancy at all and the stability was being achieved by the thickness of the hull sides plus a bit at the bow, which is on the centreline and doesn't contribute that much. As a result it had very little in the way of stability.

If the inside of the hull hadn't become free flood and was just full of water, it still causes issues because you have a large body of water that naturally flows to the low side. It's called the free surface effect and is due to the size, particularly the width, of the free surface of the water.

As someone else has said, that is why tubes are so effective. They not only provide buoyancy but they also provide it some distance from the centreline which maximises the effectiveness.

[Matt]

Learnings from the Herald of Free Enterprise right there. That was one of the key learnings from that accident. It was some ridiculously small depth of water on the car deck that would be enough to cause instability.

Originally Posted by GuyC

It's called the free surface effect and is due to the size, particularly the width, of the free surface of the water.

[spartacus]

Originally Posted by jwalker

What surprised me was how unstable it became with such a small amount of water on board.

High centre of gravity with the T-top, and the 200kg+ Yamaha engine probably didn't help.

Mako boat owners will be looking on in despair. Couldn't find this particular model, not an offshore hull, but not quite a skiff. That colour scheme seems to be available over a number of years.