10 mill$ poweryacht capsize during launch in Anacortes

[Zonker]

Carrousel Rave Tug - yeah that's our tug design too.

It's a unique thing that makes it hard to put the winch. Winch loads are 50-100 T + so building a structure around the deckhouse that can withstand that as the winch rolls in a circle is very expensive. And you have to have nobody on deck because the tow line can swing around unexpectedly if something happens. We'll see if it catches on.

Yes, sometimes a ship drags a tug sideways. Sometimes it's intentional. This is called an Escort tug. Tankers are the usual ones that have an escort because oil spills are very costly and bad. So if the tanker loses power the tug can both steer and brake the ship by swinging the hull of the tug to one side or drag sideways. Very fun trials (but kind of scary). The idea is to use the tug's own hull and skeg to develop forces >> tug propeller thrust forces. ~1.5x tug bollard pull or so. 

Like this:

Here's one of our designs. That's a Rotortug. 3 Z-drives. Very maneuverable, more like a V-S tug but you do need 3 hands to drive it!

 

[Rasputin22]

This is a classic FU!

 

[Diarmuid]

12 minutes ago, Zonker said:

Carrousel Rave Tug - yeah that's our tug design too.

It's a unique thing that makes it hard to put the winch. Winch loads are 50-100 T + so building a structure around the deckhouse that can withstand that as the winch rolls in a circle is very expensive. And you have to have nobody on deck because the tow line can swing around unexpectedly if something happens. We'll see if it catches on.

Yes, sometimes a ship drags a tug sideways. Sometimes it's intentional. This is called an Escort tug. Tankers are the usual ones that have an escort because oil spills are very costly and bad. So if the tanker loses power the tug can both steer and brake the ship by swinging the hull of the tug to one side or drag sideways. Very fun trials (but kind of scary). The idea is to use the tug's own hull and skeg to develop forces >> tug propeller thrust forces. ~1.5x tug bollard pull or so. 

Like this:

Here's one of our designs. That's a Rotortug. 3 Z-drives. Very maneuverable, more like a V-S tug but you do need 3 hands to drive it!

Jeezus, the multiplied loads on that fairlead.... Do y'all just build a titanium A frame and then add a boat under it?!?

At around 1:25, it looks like a stream of water is being directed at the fairlead. Is that a cooling device, or an optical illusion like the wake shimmer reflecting in the pilothouse windows? You have a very cool job, BTW.

 

[Zonker]

Yeah, escort tugs are relatively new (post Exxon Valdez where they were first required in Prince William Sound for all tanker traffic). 

Now they use them in narrow dredged channels like Port Hedland, Australia. If a big bulk carrier goes aground the economy of Australia ends. (only half joking) - they export about 1.2 MILLION TONS of iron ore every DAY.  That's a lot of ships having to go through 1 channel. 

The loads on the towing fairlead can be very large. It's only large steel pipe with a stainless steel lining. It's gotten so that the loads on the towlines were crushing the steel pipe, so the pipe wall thickness had to increase a lot. The fairlead legs extend under deck a long way and there are big girders running fore/aft and transversely to distribute the loads.

The water is part cooling/part lubrication so the rope can slip easier.

We joke that when they order a new Dyneema tow rope it gets delivered in an armored car.

 

[Zonker]

Re: the tug being capsized in Skookumchuck. Looks like the tug lost power (?) and the barge overtook it. I counted about 5 seconds from the time it was clear to me that the tug was in real trouble (heeling) to inevitable capsize.

That's long enough to hit the abort button on the winch and release the load. Sadly not all tugs have winches that work that way.

 

[Rasputin22]

Here is how the pushboat boys do it down in Alabama on the Tombigbee!



From another thread I just learned a new word that looks like it would apply to this incident.

al·li·sion noun \əˈlizhÉ™n, aˈ-\

Definition of ALLISION

1 obs : the action of dashing against or striking upon
2 : the running of one ship upon another ship that is stationary —distinguished from collision

 

[Rasputin22]

And here is how they do it up on the Hudson

http://www.wect.com/2019/01/25/former-henrietta-iii-crashes-into-train-bridge-nys-hudson-river/

 

[SloopJonB]

3 hours ago, Rasputin22 said:

Here is how the pushboat boys do it down in Alabama on the Tombigbee!

I remember seeing vid of that years ago - it looked like the push boat actually kept running through that - smoke from the stack afterwards.

 

[DDW]

In the Skoocumchuck video, the props are turning long after the thing's gone turtle. 

 

[toddster]

In the Skoocumchuck video, the props are turning long after the thing's gone turtle. 

Then you can hear the motor going runaway while it’s hidden behind the barge.  Until it dies. Wonder what the props were doing?