Going astern

[John Orentas]

A vaguely related question. Whenever this topic is discussed reference is made to "Right Hand" or "Left Hand" props.

 

I can never really make up my mind just what is meant by these terms. My guess would be that right hand means turning clockwise and that this is when facing forward!!!

 

Have I got it right (sic) ?

 

Have a great weekend it'll soon be time to crack open and beer or three

 

Martin

 

 

Hi Martin.

 

I don't know which is which either, better to think of them as clockwise or anti-clockwise.

 

The way I like to think of it is first imagine if you can starting an engine with a starting handle, so looking at the front of the engine it rotates clockwise. Therefore looking from the rear of the engine (and the rear of the boat) it rotates anti-clockwise.

 

Now all or nearly all gearboxes reverse the direction of rotation so your propeller rotates clockwise when observed from the rear.

 

As an aside. Boats with a twin engine arrangement will have one gearbox which rotates in the opposite direction to the other and fitted with an opposite handed propeller, mainly to negate the paddle-wheel effect. Just occasionally these handed gearboxes come onto the second hand market. It is vital that if they are used they must have the compatible prop. If anyone happens to aquire one don't be tempted simply to run it in reverse, they don't last very long when used like that.

[DHutch]

Yeah, right hand = clockwise when looking at the stern. (down on the starboard side)

 

Makes total sense to me.

- Its from the stern, becuse thats the way you look at it, you cant see the prop from the bow!

- And its right hand for clockwise, just like threads on nut and bolts.

- Its odd origanaly i admit, but it does work...

 

And as john says, most boats take a right hand prop. And many, but not all, twin prop'ed boats have counter-rotating propelers and or engines.

- This also ballences the torque of the two shafts/engines. Somthing that needs to be taken into account with higher performace craft.

 

I heared about a boat at hapton that had the wrong handed prop on it.

- the new owner had the gear box rebuilt twice before realising.

- puting it down to ware/tare at first, then only when the reverse brake-band when again in only two weeks did he and the yard twig the problem.

 

 

Daniel

[howardang]

Sometimes I loose the will to live. The reason we had to learn how to do it was precisely in order that we could manouver the boat to the side, in order to minimise any risk to the passengers by floating around in the middle of the watercourse.

 

If you want to see the evidence of how it works get on a boat and get it moving forwards at normal speed. Let go of the tiller and open up the throttle, depending on whether you have a right hand or a left hand prop the front of the boat will slew across to port or starboard, now drop the revs put the boat into reverse and open up the throttle, the front of the boat will slew across in the opposite direction, whilst it is still moving forwards.

 

My boat moves to port in forward and starboard in reverse. And as for it being a party trick, wherever possible, I use paddle action to advantage when bringing the boat alongside for mooring. The working boatmen knew how to do this and always used it to bring their boats alongside.

David, Sorry to be a long time answering you but I have been away boating.

 

I think we are talking at cross purposes. You mentioned that when taking your boat masters certificate you had been taught how to steer without a rudder and I would agree that it is possible to use transverse thrust in that way to a very limited effect, however, I would suggest that it is quicker and easier in a canal situation to use a pole to reach the safety of a bank. I have no argument about the use of transverse thrust as a part of boat handling and am grateful for your brief description of how it works. It is certainly not a party trick when used in combination with the rudder and it should be something that everyone handling a boat should be able to use to their advantage. I am fairly familiar with its effects having used it as a shipmaster quite effectively on ships both large and small for many years.

 

Regards

 

Howard Anguish

[DaveR]

OK, for the prop type and direction I hope I can put this down so that it can be followed . . . . . :

 

Hold you hand in front, four fingers slightly curled in the natural direction and your thumb out at the side (sort of hitch hiking but not with a balled fist)

 

Thumb shows the line of the prop shaft to the engine, fingers the direction of turn : which hand shows correct for your boat ? Right hand or left hand ?

 

The same is used for rope and wires, only here the thumb shows the length of rope and the fingers the fingers the direction of the lay.

 

Same can be used for determining the rotation of a winch drum. The thumb shows the direction the rope or wire is attached to the drum and the fingers indicate the turns of rope on the drum but also point in the direction the drum needs to turn. So for right hand lay wire or rope the attachment needs to be to the left and direction of turn "over the top". However by turning the hand over so the thumb points to the right then the drum needs to turn "under".

Edited August 20, 2006 by DaveR

[William Martin]

being relatively new to Narrowboats, steering while going backwards is one of the hardest things for me to understand. I have paddled racing kayaks for 25 years, some as long as 40' - and when one of these is propelled backwards, the rudder has a very significant and usable steering effect - the narrowboat rudder seems to do almost nothing in comparison - without a flow from the prop going over the rudder it has no effect - which means all the time when the prop is running in reverse.

[David Schweizer]

David, Sorry to be a long time answering you but I have been away boating.

 

I think we are talking at cross purposes. You mentioned that when taking your boat masters certificate you had been taught how to steer without a rudder and I would agree that it is possible to use transverse thrust in that way to a very limited effect, however, I would suggest that it is quicker and easier in a canal situation to use a pole to reach the safety of a bank. I have no argument about the use of transverse thrust as a part of boat handling and am grateful for your brief description of how it works. It is certainly not a party trick when used in combination with the rudder and it should be something that everyone handling a boat should be able to use to their advantage. I am fairly familiar with its effects having used it as a shipmaster quite effectively on ships both large and small for many years.

 

Regards

 

Howard Anguish

I wondered whether anyone would make that observation. We were required to demonstrate the safe and efficient use of poles to get a boat into the bank, but the Boatmaster Certificte assumes nothing, including the depth of the navigation. If you lost steerage in the middle of a river section a pole would be of little use until the boat was fairly close to the bank, hence the requirement to use an alternaticve strategy.

 

For most people the concept of loosing steerage on a Narrowboat may seem to be an almost unrealistic possibility. However, the Boatmasters Certificate qualifies the holder to steer a passenger vessel up to a designated capacity, but does not specify the design of the vessel. As understand it, the loss of steerage is more likely to occur on a boat with indirect cable operated steering, hence the reason for it's inclusion in the sylabus.

Edited August 20, 2006 by David Schweizer