Anyone row their sailing boat on / off a mooring ?

I sail a fairly heavy 18 foot boat with no engine. Where possible I would sail on and off a mooring. If there is no wind, or if I am trying to get into a tight space in a harbour, I will use the oars. For a short distance, in a tight space I will always stand up, pushing the oars. The boat is far more controllable than the boats with engines that try to get in and out of the harbour (although I have had a lot of practice).

For longer distances I would either sit down with both oars, or more often just with one sweep, using the rudder to keep her straight... all only if there is not enough wind to sail

The oars need to be long enough, preferably twice the beam, but storage can be a bit of an issue in some boats.
 
jdc said:
...my 42' boat's hull needs only ~120N (or ~12kg) of force.
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That's pretty amazing! It suggests your boat could be moved by the very smallest electric trolling motor. But discounting wind & tide influence, I suppose any thrust will move any floating vessel.

I'm looking at 2.7m (8ft 10") oars for the 17' 6" Osprey, which has 5ft 9" beam. I know it's a different question; she's a dinghy under 150kgs and has only 18" freeboard...

...but I'm confident she'll be easily driven at a useful pace, rather than just go with the tide, miles offshore as the sun sinks on a calm evening. I hope so, at £40 per oar!
 
dancrane said:
That's pretty amazing! It suggests your boat could be moved by the very smallest electric trolling motor. But discounting wind & tide influence, I suppose any thrust will move any floating vessel...
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I don't think it's at all unusual - as you say any force will move any floating vessel. Try this experiment(1) one day:
pull_5_kg.PNG


Propel the dinghy along at the speed which keeps the tow rope in a 'V' at 45 degrees (and clear of the water obviously). The horizontal force on the yacht will only be 5kg, ie ~50N. Measure the speed, eg by GPS SoG. It's surprising how low a force is needed to get a yacht going along at a knot or two.

(1) perhaps not when single-handed!
 
I and a chum crew tried rowing my Anderson 22 when becalmed off Portland Bill ( we were too tight to buy petrol ).

We were both young and physically fit but we might as well have tried juggling fog, zero progress.

However we were using the dinghy oars tied to the boathook and spi pole, with lashings on the chainplates as rowlocks.

If we'd had solid one piece sweeps like a gig and well built rowlocks it would have worked well and I now have a reinforced ( posh chrome ! ) rowlock fitting in the transom coaming, for sculling or emergency steering if the rudder gets taken out by a container or something.

I think with rowing a ' large ' sailing boat, as with most things in sailing, strong simple pre-prepared kit will see one through.
 
jdc said:
It's surprising how low a force is needed to get a yacht going along at a knot or two.
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The problem is keeping that force constant, which is the problem with rowing as soon as you are not on stroke? you are loosing speed. You might be able to heave with 15kg of force for 50% of the time but is there is 6 kg of force against you that progress suddenly becomes very slow...

The drawing above grown up is very much how long distance offshore tows work the catinary in the wire is an important part of keeping forces constant...
 
lol:

'The oars need to be long enough, preferably twice the beam, but storage can be a bit of an issue in some boats'

That'd be 13m long oars :)

I have some SS cleats to which I can tie the oars, 60cm above the water line, to the side of the rear deck.
Saw some 'long' oars at the chandlers last week ....

I have tried sailing off the mooring, too many times.
As the boat has a dagger board, there is no steerage until I have a decent flow over the foil, by the time that happens I am too often stuck on the mud.

Interesting re watts per hour, the arm cycle machine at the gym says 750 W per hour .....

I shall try with the shortish dinghy oars first ........
 
dancrane said:
The advantages of a trimaran's minimal displacement and slender hull must favour a manual-auxiliary,
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No, the light displacement isn't necessarily an advantage - a heavier boat will keep going between each pull/push (that's perhaps why an earlier poster had little success with duette/sonata).

The idea is to only gradually get the boat moving (different mindset to motoring or rowing a light dinghy), and then maintain a slow (1 knot or so?) but steady speed you can maintain.

With a boat that holds its course well, one long sweep will probably be better than two shorter oars.

PS Apparently Slocum wrote of propelling his 40ft boat with a sweep.
 
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I take the point about generating and maintaining momentum.

But if one uses a single oar (other than sculling over the stern), isn't it a considerable waste of effort, to keep the rudder substantially off-centre?
 
:D

I used the pair Oars / Sweeps pic below to propel my 18ft open Seine ex fishing boat along - these oars are over 40 years old (as thats how long i've had them) 2" or 50mm shaft diameters - 9 ft long - ok so not fast but moves along at a steady pace - allowing for slight rest between each stroke - they might have been made for pulling life boats originally -

View attachment 32034
 
French bloke sculling in 2012

A short video of a french bloke sculling he came down river he did it a couple of times a day, once empty and then with 6 or seven blokes on board . Took vid' in L'Aber Wrac'h in early august 2012, The blokes were later working on the shellfish beds was a daily event for six or seven days
It was Quite a heavy wooden boat and he sculled past probably at least a Mile and a half in my line of sight and into the tide at times the handle and blade were interesting the blade very flexible the handle was 2 one for each hand
[video=youtube;xUo2nFpKlR4]http://www.youtube.com/watch?feature=player_detailpage&v=xUo2nFpKlR4[/video]
 
dancrane said:
I take the point about generating and maintaining momentum.

But if one uses a single oar (other than sculling over the stern), isn't it a considerable waste of effort, to keep the rudder substantially off-centre?
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It would be, but you shouldn't need the rudder substantially over. The key to it is having a goodly length of sweep (e.g. 20+ ft), so that you are pushing along parallel to the boat's centreline, not sweeping round in a short circle and spinning the boat.

I had a quick look, without success, to see if I could find an extract from Maurice Griffiths or somesuch on the subject. I did, however, find reference to someone using a sweep to propel a Thames barge. For 4 hours!
 
LittleSister said:
It would be, but you shouldn't need the rudder substantially over. The key to it is having a goodly length of sweep (e.g. 20+ ft), so that you are pushing along parallel to the boat's centreline, not sweeping round in a short circle and spinning the boat.

interesting discussion. I spent many hours of my youth rowing 18 ft clinker sea scout boats as part of a crew and also solo.
1 Interesting thing about boats as compared to say a car: at standstill there is no (zero) friction to overcome for a boat to get it moving - only inertia. In theory and in practice as defined by Newton, a tiny force on a boat will accelerate it it to the tiny speed at which the the acceleration force is equal to the resistance "force" of friction. The resistance for a boat increases from zero as a (geometric) function of velocity.( A car on the other hand has a large static resistance to overcome before it will start to move at all, but then the rolling resistance is almost constant so more power = more speed until air resistance becomes significant.)
What this means in practice is that the merest zephyr or a light stroke from a paddle will move your boat.
However the faster you want to move it the more power is required.
2 If rowing with single oar , then have the rowlock on the centre line of the boat and give or take the arc of the oar sweep the thrust on the boat will be linear.
What makes the boat go in circles with a single oar is not the distance from crutch to blade, but the distance from boat centre line to crutch.
3 I remember as 15 year old doing a physics experiment where the whole class took turns to weigh themselves and then run up a double flight of stairs against the stop watch.
from this we calculated kilowatts developed by the individual. As i recall the best athletes amongst us achieved something like 350- 400 watts over the 15 seconds.
4 http://www.theblurb.com.au/Issue36/LeakyBoat.htm One of the best adventure books i have read - these guys rowed an 18 ft clinker boat hundreds of kilometres.
Certainly made me feel like a wimp!
5 I have often thought about fitting crutch sockets on my 26 ft Trailer yacht so that i could row her from standing in cockpit. Now i have resolved the starting issues with my previously unreliable outboard, i have got lazy and those thoughts have receded, but i cant help thinking that one day when the engine fails and the wind doesnt blow, being equipped with suitable oars and crutches could be a "get out of jail free card."
cheers
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Looking at that video of sculling, it strikes me as avery inefficient operation.

Anybody like to hazard a guess as to what percentage of the energy input of a sculler is translated into motion, compared with same with oars?
 
simonfraser said:
lol:

have some SS cleats to which I can tie the oars, 60cm above the water line, to the side of the rear deck.
Saw some 'long' oars at the chandlers last week ....

I have tried sailing off the mooring, too many times.
As the boat has a dagger board, there is no steerage until I have a decent flow over the foil, by the time that happens I am too often stuck on the mud.

.....
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Heath Robinson tying oars to cleats...... unlikely to be satisfactory. You need a fixed hard verticle surface to push against. Winch drum would be a better option.

If you have problems with steerage when sailing on or off the mooring, I am afraid you are not that likely to find rowing satisfactory... likely to be too much skitting about. Longer oars will be better though, as it will move the centre of effort away from the midpoint, and give you a bit more control.
 
Thank you John the Kiwi - very good info on the subjest, and practical evidence to boot.:D

John the kiwi said:
LittleSister said:
It would be, but you shouldn't need the rudder substantially over. The key to it is having a goodly length of sweep (e.g. 20+ ft), so that you are pushing along parallel to the boat's centreline, not sweeping round in a short circle and spinning the boat.

interesting discussion. I spent many hours of my youth rowing 18 ft clinker sea scout boats as part of a crew and also solo.
1 Interesting thing about boats as compared to say a car: at standstill there is no (zero) friction to overcome for a boat to get it moving - only inertia. In theory and in practice as defined by Newton, a tiny force on a boat will accelerate it it to the tiny speed at which the the acceleration force is equal to the resistance "force" of friction. The resistance for a boat increases from zero as a (geometric) function of velocity.( A car on the other hand has a large static resistance to overcome before it will start to move at all, but then the rolling resistance is almost constant so more power = more speed until air resistance becomes significant.)
What this means in practice is that the merest zephyr or a light stroke from a paddle will move your boat.
However the faster you want to move it the more power is required.
2 If rowing with single oar , then have the rowlock on the centre line of the boat and give or take the arc of the oar sweep the thrust on the boat will be linear.
What makes the boat go in circles with a single oar is not the distance from crutch to blade, but the distance from boat centre line to crutch.
3 I remember as 15 year old doing a physics experiment where the whole class took turns to weigh themselves and then run up a double flight of stairs against the stop watch.
from this we calculated kilowatts developed by the individual. As i recall the best athletes amongst us achieved something like 350- 400 watts over the 15 seconds.
4 http://www.theblurb.com.au/Issue36/LeakyBoat.htm One of the best adventure books i have read - these guys rowed an 18 ft clinker boat hundreds of kilometres.
Certainly made me feel like a wimp!
5 I have often thought about fitting crutch sockets on my 26 ft Trailer yacht so that i could row her from standing in cockpit. Now i have resolved the starting issues with my previously unreliable outboard, i have got lazy and those thoughts have receded, but i cant help thinking that one day when the engine fails and the wind doesnt blow, being equipped with suitable oars and crutches could be a "get out of jail free card."
cheers
Click to expand...
Click to expand...
 
John the kiwi said:
2 If rowing with single oar , then have the rowlock on the centre line of the boat and give or take the arc of the oar sweep the thrust on the boat will be linear.
What makes the boat go in circles with a single oar is not the distance from crutch to blade, but the distance from boat centre line to crutch.
Click to expand...

Yes, if all other things were equal, you'd put it on the centre-line, but they're not!

The disadvantage of having the rowlock to one side of the boat (on, say, the toe rail or cockpit coaming) is quite small, especially on a boat which holds it course well, and likely to be easily correctable by application of a small amount of rudder. That disadvantage is likely to be greatly outweighed by the advantage of having greater length (leverage) of sweep inboard of the rowlock, and being able to operate the sweep from the most comfortable position (likely to be the middle of the cockpit).

The distance from crutch to blade does make a difference to how much turning movement the oar/sweep makes, but in the opposite way to what many people assume. The longer the better in that regard. A longer sweep enables you to get a decent length of pull with a shallow arc virtually parallel to the boat's course. With a shorter one you will be either pulling in inefficiently short 'dabs', or generating more turning and wasted effort by describing a deep arc.
 
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Romeo said:
Heath Robinson tying oars to cleats...... unlikely to be satisfactory. You need a fixed hard verticle surface to push against. Winch drum would be a better option.
Click to expand...

Tying with rope might not be an ideal long term option, but is good for working out best positioning for comfort/advantage. You can then rig something more robust/elegant.

You will probably need to 'tie' the oar in both directions.
 
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