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nick hall

Lateral movement before stern thrusters

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I've a question that has been nagging me for years.

Stern thrusters are now common place but before they were how did ships perform lateral, or sideways movement at the stern. The only way I can imagine is to have the rudder at 90 deg. and possibly counter rotating propellers.

Hopefully someone with nautical knowledge can explain all. Appreciate any answers.

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Jimmy Ayers at TT cracked this in the late 60s.  Three props, twin rudders.  Side props run ahead, pushing water into the twin rudders set to whichever way the stern is required to go.  Central prop set to astern to counter the forward thrust from the side props.  Result - sideways motion.  Not many ferries outside TT cottoned on to it though.  And I think PoD and PoC were the last ships built with it.

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So.....the Ayers ships that were built with this design were FE4-8, the four SVs, the Blue Ribband trio, and the two Chunnel Beaters.

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There were a couple of other unique design features of the TT ships.  The main other one was the bow rudder.

That’s why TT ships were uniquely able to dock at the original TT berth at Southampton, to reverse half way up Portsmouth harbour, and to depart Calais astern.

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On the non ferries, Merchant and even Coasters you used a tug!!...Most in those days of my youth were single screwed and pigs to control at times..Essential to get the bowline and the backspring out and then a stern quarterline and drag her in...basically. If you were lucky enough to have twin diesels then one could go ahead and the other astern the helm being full over opposite to where you wanted to go and err pray..But most skippers and pilots favoured tugs as it did less damage to the paintwork😁

Edited by Paully
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As you suggested and Colin confirmed above. If the vessel is trying to come alongside, port side to, and she has no thrusters at all (bow or stern), the standard technique is to get the bow in whilst fully manoeuvrable and get a bow warp ashore. Rudder(s) hard to starboard, port engine ahead, starboard engine astern. Adjust throttles to control fwd or astern movement and, God willing, the stern will gracefully glide in to the quay. With a single engine, the trick is to coordinate fwd and astern thrust with stbd and port rudder. Old hands make it look easy. I stop, think, look at wind and current and say a little prayer....

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Yes, the traditional seamanship involves lots of clever use of warps (ropes).  Especially useful in departure, when powering forward against a bow spring brings the stern out nicely.  (As Colin says, wind permitting!).

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And if you happen to be berthing into the tide, it’s easy peasy (apparently!).  You just ferryglide in sideways by motoring forward at the same speed as the current and pointing the bow a small angle in the direction you want to go.

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When you ferry glide a sailing yacht into a gap on the end of a pontoon, between a stack of three boats, and a stack of 4 boats, with a space all the way in between them, in 40 knots of breeze, single handed at the Sablons, and the skipper of a school boat shouts at his students to come and watch, the pressure mounts and the applause is a relief....

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9 hours ago, Gareth said:

Yes, the traditional seamanship involves lots of clever use of warps (ropes). !).

And prayers of course

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And prayers of course

Combined with expletives, both from yourself and the owner of the boat you just hit...

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Talking of expletives and prayers, the other thing that caught some pilots out were the number of compressed air shots they had `to play with`..When ships were real and they had engine room telegraphs, instead of joysticks, the main engine(s) were started with compressed air, called a shot. So going from Dead Slow to stop to Slow Astern to Stop to Slow Ahead and you`d lost a couple of shots. I remember one day at Durban with a Pilot that thought it was a jungle drum, till the Chief Engineer rang the bridge to tell them he hoped we were alongside because there was only 2 shots left and if not he`s going to need another tug......quick

   The story as told by the third mate, cannot be repeated on here, but there was a lot of panic on the bridge and very expeditious use was made of warps and springs fore and aft....and lots of oaths and prayers...

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On 28/04/2020 at 19:26, Gareth said:

There were a couple of other unique design features of the TT ships.  The main other one was the bow rudder.

That’s why TT ships were uniquely able to dock at the original TT berth at Southampton, to reverse half way up Portsmouth harbour, and to depart Calais astern.

Jimmy Ayers was a genius but the bow rudder he just copied from the railway ships, which were all built with them from the passenger steamer days up to the 1980/81 Saint class (BR) and the Champs Elysees (SNCF).

Ayers did try out the pretty unique bow propellor though on his Spirit class; this was reportedly so they could most easily manoeuvre into the original berths next to the Gare Maritime in Calais until the eastern part of the harbour was opened up, which presumably is why it wasn't seen again on the Pride of Dover and Calais.

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On 28/04/2020 at 19:10, nick hall said:

I've a question that has been nagging me for years.

Stern thrusters are now common place but before they were how did ships perform lateral, or sideways movement at the stern. The only way I can imagine is to have the rudder at 90 deg. and possibly counter rotating propellers.

Hopefully someone with nautical knowledge can explain all. Appreciate any answers.

Twin screw inward turning CPP ferry with Bow Thrusters and Quay on starboard side.  Rudders hard to starboard, port CPP ahead, stbd CPP astern to arrest any headway as if you pick up too much speed your pivot point moves fwd and you'll make life difficult for yourself, Bow thruster thrusting to push the bow to port and voila you're moving sideways.  Slow and steady always wins the race with manoeuvring.

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On 28/04/2020 at 19:26, Gareth said:

There were a couple of other unique design features of the TT ships.  The main other one was the bow rudder.

That’s why TT ships were uniquely able to dock at the original TT berth at Southampton, to reverse half way up Portsmouth harbour, and to depart Calais astern.

I think I remember that one of the Super Vikings was able to face the right way for the Queen (probably her Jubilee Fleet review) when most others weren't?

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