Running engine in gear on swinging mooring

NormanS said:
Well, I have what you might call a motor sailer, actually a decksaloon ketch. For many years I have been in the habit of leaving the boat at anchor for periods of four weeks, in sea lochs in the Outer Hebrides. I use a Bahamian Moor, and you can bet your bottom dollar that each anchor is subjected to prolonged full revs, to give me the confidence that the anchors will be capable of withstanding whatever the weather throws our way. If your anchor cannot withstand full revs, please don't come sailing in Scotland, until you upgrade your ground tackle
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If I put my boat into full throttle astern I’m pretty sure I’d drag any correctly sized anchor. 200hp 6 pot turbo diesel. I’d be disappointed if I didn’t. And mine’s only a baby compared to many.
 
You have got me thinking. I am sure it does on my saildrive boat??

Then again there is no prop walk........?
 
Ian_Rob said:
You have got me thinking. I am sure it does on my saildrive boat??

Then again there is no prop walk........?
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No experience of saildrives but found this on Wiki

Traditional sailboat transmissions consist of a simple horizontal output shaft extended rearward from the engine, through the stern via a stuffing box. The saildrive has several advantages over the traditional sailboat transmission: smaller horizontal size, no stuffing box to maintain, and the propeller is mounted horizontally instead of at a downward angle.
Saildrive also reduces propeller walk, reduces vibration, and is more efficient.[1]
 
We have often got off a pontoon when there is very little room aft, using a warp at the bow , the engine in reverse and the rudder hard over. Is there a difference?
 
Ian_Rob said:
We have often got off a pontoon when there is very little room aft, using a warp at the bow , the engine in reverse and the rudder hard over. Is there a difference?
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I still doubt the rudder is having any effect, again no water flow over it. Next time try with the rudder in the opposite direction and see what happens.
 
In forward or reverse there is water flowing over the rudder. I think you will find it does work.

Easier with a wheel that can be locked off.
 
Ian_Rob said:
We have often got off a pontoon when there is very little room aft, using a warp at the bow , the engine in reverse and the rudder hard over. Is there a difference?
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Are you sure? Using a bow spring you motor ahead and prop wash, not walk, helps spring off. You motor astern with a stern spring and the boat's rotation is induced by the off -centre resistance to movement astern of the spring line , not by water flow over the rudder.
 
Again you get me thinking. As my boat is a saildrive, prop walk is negligible and can be ignored.

All I am saying is that with my bow held by my mooring buoy and with the prop in reverse, I can make the boat pull left or right by applying left or right rudder, effectively causing her to swing either way around the fulcrum point of the mooring.
 
WindermereColvic said:
I find that when in reverse gear on my swinging mooring , the prop walk slowly spins the boat in a circle. Has anyone found a solution to this?
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Surely if you turn the helm slightly the water flow will counter the prop walk? I used to live in Essex and back in the day the cockle boats used to go to the shelfish beds and anchor until the tide dropped, then when the cockles were exposed they would get out and scoop them into baskets. To make the job easier, as the tide was dropping they would put the engine in reverse and spin the boat round the anchor, "blowing" the cockles into a pile around the anchor.
 
If running the engine not under load caused glazed bores I dread to think what most tractor engines are like. Farmers rarely stop the engine once started, yet leave the tractor idling whilst they do all sort of stuff.
Many plant engines idle for ages between duty cycles.

It's a myth.
 
LittleSister said:
Why not just go for a spin in the boat?
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eddystone said:
Because the engine is currently inoperable;
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?
If the engine is inoperable, then you won't need to worry, as you did in your first post (quoted below), about whether it would be safe to run your engine in reverse while still on the mooring.

eddystone said:
4.4 ton displacement boat on swinging mooring with 30hp motor. I will need to run the engine in gear (reverse) to purge air from the cooling system when refilling.
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When you do get eventually get your cooling system reassembled, why not go for a spin to warm up the engine and purge air from the cooling system (and enjoy the scenery), rather than sitting with the engine on in reverse on the mooring, worrying about whether you are dragging the mooring?
 
LittleSister said:
?
If the engine is inoperable, then you won't need to worry, as you did in your first post (quoted below), about whether it would be safe to run your engine in reverse while still on the mooring.



When you do get eventually get your cooling system reassembled, why not go for a spin to warm up the engine and purge air from the cooling system (and enjoy the scenery), rather than sitting with the engine on in reverse on the mooring, worrying about whether you are dragging the mooring?
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OK sorry the current status of the engine is not relevant but I don’t want to cast off and then have to deal with an overheating engine because I haven’t got the air locks out when refilling cooling system
 
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