Opions sought

[TheBoatman]

As those of you who know my background, amongst other things I'm an RYA power boat instructor. I was lucky to be taught/coached/trained by Ramsgate fishermen/RNLI coxons. However this weekend I came across an instructor that had the following ethos when teaching candidates on how to drive power boats.
1. Never use astern gear.
2. Proceed at "burbling speed". Which meant engaging forward gear then immediately going to neutral, then back into forward gear again. thus making very slow forward motion.
This goes against everything I have ever been taught
"What do you think"?

 

[zefender]

Surely it depends on the boat. There are many power boats that need to go faster than 'burbling speed' in order to have safe control.

 

[tcm]

Re: eh?

there must be more to it than this. Can't see how you you stop a boat if not allowed to use engines astern. Or, if going backwards, um well how would you do that?

 

[nicho]

Likewise, many larger powerboats at tickover speeds, are making 6+ knots, too fast for negotiating marinas etc, even with only one engine driving - hence the need to nudge in and out of gear. Don't understand the non use of astern propulsion though.

 

[pugwash]

This is how you do it.

True story. Pilot taking Japanese cargo ship into Rotterdam. "What are you loading, Captain?"
"Just making some engine repairs, Pilot."
Some time later, ship approaches the right-angle turn into the dock area just before the bridges. Pilot orders: "Hard astarboard, full astern!"
"Engine won't go astern, Pilot, that's why we need repairs."
The pilot dropped both anchors and didn't hit anything.
I guess that's how you do it.

 

[AJW]

I had a similar experience doing a PB2 course with the RAF sailing assoc. (Not that I have any military connections I hasten to add.) We were supposed to do all our manoeuvering on the basis that our astern gear might not be working which of course we wouldn't know until needed it.

This was contradictory to what I was taught as a lad e.g. coming alongside, smartly put the outboard on opposite lock and give a burst astern to stop you and pull the stern in. Same thing works with single outdrives of course.

Seemed to be a very odd approach given the odds on your astern drive failing at that particular point. Also seemed to imply that you would always be manoeuvering against the tide/current/wind which of course is good practice if you can but is not always possible!

Mind you with some RAF warrant officer screaming at you disagreeing seemed to be the wrong thing at the time!

AJ

 

[bedouin]

Re: Opinions sought

Curiously, that is how I handle my (sailing) boat under power.

(a) I never use astern except at the very last moment to take weigh of the boat once the lines are ashore - because she is totally uncontrollable with the engine going astern but the boat moving forwards

(b) I often use the approach of keeping the engine in neutral, and using short bursts of ahead just to maintain minimum steerage way.

BUT, I wouldn't have thought the same considerations applied to a power boat (don't know, never been on one).

 

[jamesjermain]

This surprised me though I am no expert and haven't undergone powerboat training for about 20 years. I can see the point about big, powerful boats probably doing five or six knots at tick over, but an outboard or outdrive powered boat has no directional control except through the thrust of the propellor.

When I learned to handle twin engined boats, a large part of the time was spend practicing steering and parking using engines only, for which astern was an important element.

I can see that learning to handle a boat using only forward gear might be part of the syllabus, in case astern gear failed, but not the whole of it.

JJ

 

[Guest]

This is not a dig

Posting as a sailor I find it scary that someone would design a craft which has no steerage below 6 knots when it might well enter waters where the maximum allowable speed is say 4 knots! What do harbour masters make of this?

Next time I'm coming home up the Hamble with a big job behind me I'll treat it with much more respect!

Geoff

 

[tcm]

no astern engine on pwrboat? Different from sail..

..but not much. Efectively it would be an utter pain with no astern on a sailboat, and if not causing actual damage, it would be a good crew that got lines ashore to stop a boat dead in the water. But many powerboats (and almost all boats in the med) must moor stern-to. I have got a boat in twice with only one engine (out of two) but only with assistance of dinghy (acting as tuglet(?)) and on both ocassions i did have astern. Would not have tried without astern, ecept with two or more boats to tow/ push/stop.

There must be more to the statement of "teaching not to use engines astern" in fact raving stupid imho. It is a definite anchor down and have a think jobbie. Wouldn't able to give way to sailboats for one thing, would be able to stop in a small distance area for another. I await to be convinced that this isn't misheard, cos as it stands it seems dangerous if not illegal. Insurance company would not be impressed if anyone went to sea without astern available, or returned to port excpet to deliver emergency blood casualty to fuel pontoon. The situation is only a little better if by "powerboat" they mean RIB, but still not much better imho.

 

[jamesjermain]

Re: This is not a dig

'No steerage' is a trifle of an exaggeration. But for some powerboats, going slow does mean disengaing gear from time to time when steerage may be restricted if it relies on vectored thrust

JJ

 

[tcm]

Powerboating under 3knots

Indeedy. Loads of powerboats tickover at 6 knots or more. With a relatively flat planing hull, they don't have "way on" much under 5 knots, and need both engines (with forward and astern available) to control boat movement: the rudders do nothing much under 5knots: control is managed by slipping in out of gears and using reverse on both engines. Also possible (but less manouevrable) with one engine, though best if the boat was designed for one engine, and more likely to be a light boat or have keel which gives slow-speed way on.

 

[BarryH]

When I took the RYA level 2 powerboat, there was an exercise in it that you could not do if you didn't put the engine astern. Namely going round a bouy kepping the boat as close as poss. Then there was the manourvering bit turning the boat in its oen length. They guy that I had as an instructor was ex Thames division Met Police. Nice guy, new what he was doing with a boat. So I reckon the guy saying don't use astern is talking bo***x INMHO.

 

[Peppermint]

Re: When giving instruction

I'd of thought you might teach various methods of using the controls available and then concentrate on a few typical "control failure" scenarios.

This blokes alleged technique sounds fishy to me.

It's not just powerboats that don't steer until a few knots are slipping by. Loads of longkeelers, particularly with offset props, are a complete lottery until you get them moving a bit.

 

[tcm]

Re: When giving instruction

agreed re longkeelers. But you are most part knackered with no astern on a powerboat. Alright, i'll qualify: given a sailboat or powerboat of the same length with no astern, which to choose to bring into harbour? Easy: the sailboat cos it has likely less freeboard, and (as bedouin alludes) far more chance of getting early lines ashore to stop the boat moving fwd. But even over 50/60 feet tops (or over 30 feet if you've paid and it ain't a charter boat!) it's anchor down outside the harbour and get a dinghy out to go and get another dinghy to help out, imho.

 

[TheBoatman]

Re: When giving instruction

It looks like I need to give a little more info here!
1. It was a PB2 course and we were obviously following the laid down course
2. Boats being used were RIB, 2 displacement work boats and one semi planning boat.
3. RIB is 5 mtr with 50hp outboard
4. One displacement boat is 22' with 30 hp inboard diesel (conventional shaft)
5. Other displacement is 30' ex ships lifeboat with 18hp inboard and 3 tons of concrete ballast to help keep it in the water<s>(conventional shaft)
6.Semi is 23' and has 70hp inboard diesel (conventional shaft)
7. His comment about astern was also followed by "there are no brakes on a power boat".
Now I was always told that there are "brakes" on a power boat, all be it that some are decidedly dodgy. Some boats steer backwards a treat whilst others would only go where they wanted too despite any efforts from you.
I cannot see the reason for "burbling speed" when you still have 200 yards to go to the mooring (which is not marina based).

 

[TheBoatman]

JJ I have also driven such boats and have found that if its doing 6 knts on tick over then as soon as you touch it astern it stops bl***y quickly but likewise if you are a bit tentative and theres a decent cross wind you'll jolly soon find yourself in trouble.

 

[tcm]

Re: aha, perhaps i understand

OKay, here's how i read it then. Your friend is fed up at the number of people who want to whoosh up to as mooring in powerboat, stop dead using revrse and then work out how to get hold of mooring, and is getting drivers used to accurate slow-speed and even minimum-speed manouevres.

With no astern, the game is to approach against wind/tide using only fwd gear and take hold of the mooring without going forward, oops back a bit oops, fwd back, oops forwards etc. Essentially the same as a sailboat manages to do most (but not all) times but at least with the RIB the helm can see the mooring buoy all the time, no guessing at where buoy is under the bows.

If this is the correct interpretation, it's quite good exercise, imho. What he calls burbling speed is the very minimum speed thru water that will allow the the boat to still have way on, and not drift like a cork, such that soon after cutting power, the boat will stop sedately right next to the mooring buoy just as the boat stops. No, make that a very good excerise, invaluable for man overboard and lots of other instances.

The 200yards is praps a bit overdoing it, but gets one used to going slowly- a strange sensation for a powerboater perhaps? I hope not.

 

[claymore]

I too have my powerboat instructor award and agree about not using reverse and also slipping in and out of gear. I think this becomes second nature when you are working with a group of dinghies where people are being taught. You don't need much speed, don't want to create wash and if you are having to move quickly, you've probably let a situation develop too far.
Like Bedouin, this is how I control my boat and always judge things so that I don't have to use loads of reverse to take the way off and prevent a collision.
When I was teaching sailing for a local authority, the boss used to discourage us from using reverse on the ground that if you were depending on it to get you to stop, and the mechanism failed, you might go crashing into a wayfarer full of kids which wouldn't have been very good! The lesson stuck I suppose as I rarely use it and take pride in being able to judge how long it will take to slow down to a stop and then using the throttle accordingly.

regards
Claymore

 

[Mirelle]

Re: This is how you do it.

I have found, over the years, that Rotterdam pilots are often given to embroidering stories. This one is "remarkable", in two respects.

1. Slow speed crosshead diesels are two stroke, direct reversing. No gearbox or clutch to fail. Stop the engine, then re-start it running backwards. OK she might have been a steamer, but I cannot see why the astern turbine would not work when the ahead turbine was OK.

Assuming a slow speed diesel, if he had no air to go astern, he would have had no air to start after stopping, either. I have never heard of such a case. The start air system is one of the most "bullet proof" bits of any ship's engine room.

However, the tale would make sense if the ship had a variable pitch propeller which had (correctly) failed to the full ahead position. That is possible.

2. I absolutely cannot conceive of any Japanese Master who would embark a Pilot without telling him of any limitations on the ship's ability to manoevre, any more than a Dutch or a British Master would. <P ID="edit"><FONT SIZE=-1>Edited by mirelle on 26/11/2002 19:29 (server time).</FONT></P>