Horrendous Ship Collision

[Dockhead]

Wow!

https://www.youtube.com/watch?v=svFwsJsHHGs

The story is here:

Grand Rodosi/Apollo S – Astern Warning » Maritime Accident Casebook

Apparently the Chief Engineer screwed up big time. He thought he had stopped the main engine and gotten it turning in reverse before giving fuel, but it was still turning ahead. So instead of reversing, the ship accelerated in ahead. Oops!

For those scratching their heads -- big ship engines are mostly two-stroke diesels. They don't have gearboxes -- to turn the screws in reverse, you make the engine run backwards. You do this with the compressed air starter.

[DotDun]

Wow.

I hope his engineering skills can assist his new career of flipping burgers.

[valhalla360]

Black Friday parking rage?


Actually, reminds me of an incident we had many years ago. It was a twin engine fly bridge boat.


We were taking a trip across to Canada for the weekend but on the way, there was something odd with the way it was handling so we turned around to go back to our dock where we had access to the car. We called ahead so some of our friends were waiting when we came in (of course fiasco's always have an audience).


Coming down the fairway, I typically put her in neutral as we get close to bleed off a little speed, then pop the port engine in reverse as we turn into the slip. This slows us down some more and helps with the turn....


Except when I put it in reverse we were still going a little too fast. So what is the obvious thing to do, goose the throttle a bit. Well, instead of slowing down, she surged forward and now we are aimed right at the camper top on the back of a nice searay.


Luckily I managed to crank the wheel around and miss the other boat but now the steel bulkhead at the end of the fairway is coming up fast. I turned the key off to kill the engines and came in under rudder only. Luckily, the end slip was empty and she slid into place with only a slight bump.


Then the young girl who manages the marina pulls up in her golf cart going on about how we can't stay there. I must have given her an evil eye because she just got quiet and got back in her cart and left.


Turns out, something got messed up and the transmission was locked in forward gear, so moving the gear lever was doing nothing.

[Blue Stocking]

Spent some time in the engine room of a 750 passenger, cruise ship tender, fitted with 2 direct drive, 5 cylinder Crossleys. Engineer driver stood facing the telegraphs, with throttle levers standing vertically out of the floor plates in front of him. 3 ft diameter wheels, with suicide handles, at his left and right hands, rotated the cams and injected air to reverse the engines. Got active when there was a stiff breeze and had to warp alongside a swinging ship at anchor.

[Moody46CC]

'bout the only thing the insurance company can do is to try to minimize the number of zeros on the left side of the decimal point.

[HappyMdRSailor]

Holy smoke... That was insane...

Can you however... Imagine how much worse that could have been....

If the boat on the dock was using a deep fryer at the time???

[Dockhead]

Originally Posted by HappyMdRSailor

Holy smoke... That was insane...

Can you however... Imagine how much worse that could have been....

If the boat on the dock was using a deep fryer at the time???

Kidding aside, think about how much worse it would have been if anyone had been aboard the tuna boat. I have never seen a vessel just disintegrate like that (apart from as a consequence of naval warfare). Chances of survival for anyone below decks on the tuna boat would have been pretty slim, I would think.

[carstenb]

Hey - don't worry, that'll buff right out

[ontherocks83]

Again people here need to do their proper research, this was not a collision.

Due to extreme budget cuts it has gotten way too costly to haul a boat out and pay a dozen employees to cut up and scrap the old boat. So by necessity they have now invented a new scrapping method. It takes only a fraction of the time, does an even better job, and is WAY more fun.

[K_V_B]

Originally Posted by Dockhead

For those scratching their heads -- big ship engines are mostly two-stroke diesels. They don't have gearboxes -- to turn the screws in reverse, you make the engine run backwards. You do this with the compressed air starter.

The ship I was on this summer had a big two stroke engine as well. They kept it at constant RPM, and did everything (including reversing) with an adjustable propeller.
Basically the engines' governor would keep the RPM constant, the captain on the bridge adjusted the pitch.

[Dockhead]

Originally Posted by K_V_B

The ship I was on this summer had a big two stroke engine as well. They kept it at constant RPM, and did everything (including reversing) with an adjustable propeller.
Basically the engines' governor would keep the RPM constant, the captain on the bridge adjusted the pitch.

That's probably a better way to do it, but most ships have fixed propellers and have to reverse the engines.

They do it by injecting compressed air into the cylinders, using the same system they use to start the engines.

By the way, I have a snowmobile which has a similar system of reversing. Except that instead of a Chief Engineer in the engine room, my snowmobile as an absolutely ingenious bit of technology.

It's a 600cc, 120 horsepower direct injected Rotax engine, and what a beautiful piece of machinery it is -- I think it weighs like 30 kilos -- highest specific power of any engine of any type I've heard about.

You press a button to evoke reverse, and the computer kills the ignition and lets the engine start to run down, then with amazingly precise timing, gives a spark very early on one compression stroke, early enough to kick the piston down and back around in the wrong direction, and presto -- the engine is running in reverse. No gearbox needed, which means significant weight savings -- key to snowmobile performance.

[bcn]

Originally Posted by Dockhead

It's a 600cc, 120 horsepower direct injected Rotax engine, and what a beautiful piece of machinery it is -- I think it weighs like 30 kilos -- highest specific power of any engine of any type I've heard about.

MotoGP renders 250hp from 1000cc - 4 stroke, no turbo

[nigel1]

Originally Posted by K_V_B

The ship I was on this summer had a big two stroke engine as well. They kept it at constant RPM, and did everything (including reversing) with an adjustable propeller.
Basically the engines' governor would keep the RPM constant, the captain on the bridge adjusted the pitch.

This to can lead to some monumental disasters.
One or our boats working in Australia was heading back to port for crew change, and the engineers ask the skipper if they could take control of the prop pitch (two props), and they would bring the pitch up to maximum engine load to squeeze out every last bit of speed.
So control was passed to the engine room.

Near to the fairway, the skipper took control of the pitch back on the bridge, but the engineers left the pitch control levers in the full ahead position.

15 minutes later, boat is alongside and tied up. Skipper has the pitch control set to zero, calls engine room and tells them they are finished with engines.
Engineers then take back control of the engines to shut them down.

It was a bit of a mess, fortunately no one was ahead of them, but they parted all the mooring lines, lost the gang way and ripped the fenders off the boat and the dock.

[Dockhead]

Originally Posted by bcn

MotoGP renders 250hp from 1000cc - 4 stroke, no turbo

I mean specific power by weight, not by capacity.

The Rotax is mildly tuned, in terms of specific power by capacity -- 200bhp/liter. At only 7000 RPM.

[bcn]

Originally Posted by Dockhead

I mean specific power by weight, not by capacity.

The Rotax is mildly tuned, in terms of specific power by capacity -- 200bhp/liter. At only 7000 RPM.

Mass is <60kg. And yes 18000 rpm.
The old 500cc 2T engines gave 160hp and were a bit lighter.
125cc 2T 45hp+