Manoeuvering Tight quaters

[copaco]

It's a single right hand prop 40' cruiser, so I'm considering WINGSAIL,TILLBURY,and HANK OW.In a marina, so no currant,just wind on stern mainly.Thanks all.

[mvweebles]

As a guy who has taught 100's of people close-quarters maneuvering in SF Bay, not everything is possible - there are tools, but no magic bullets, no special springlines. Knowledge and technique only go so far - there are situations that cannot be overcome without unacceptable risk.

True Story: I used to liveaboard at a notoriously windy marina and watched a spectacularly ill conceived docking attempt by a MacGregor 65 that had lost it's engine on a daysail and decided to sail into their slip. They aborted too late and decided to bail-out into a more convenient slip that happened to be open. They hit the landing with such force that their bow rode-up over the end and tangled with the pulpit of the boat on the other side of the dock doing $20k in damage between the two boats. Further, when the boat who's slip they now occupied returned from their day sail and found their slip occupied, they tried to turn around and ended up running aground. If you ask me, it was pretty selfish and inconsiderate of the MacGregor to do what they did, which I'm sure they would agree with 100% having seen the consequences of trying to force a docking.

Here are the simple facts: until tethered to earth, a single engine boat has two tools: prop-walk and rudder wash. Sounds like the OP's boat has a right-hand prop which 'walks' to port in reverse. Landing to starboard means not just relinquishing one of your two tools, but it's fighting you. I'm a pretty good helmsman and have the same problem with my boat - not everything is possible. Unfortunately, some helmsmen get a bit nervous and grab the throttle thinking more RPMs will help (rudder wash), but often make the situation - and potential for damage - much worse.

I can think of some springline maneuvers, but these would take a lot of practice and crew choreography well before needed (thought: consider backing-in and getting a line from an aft quarter cleat vs the bow). But from a practical approach, if you're boat is like mine and really struggles to complete the turn, you have two options:

#1 Land to port, your preferred side. On exit you will be making a starboard turn, your preferred direction on your boat. It is safer coming in, safer going out. I cannot think of why you might need to land to port, but unless there is a very strong reason, this would be my go-to. If you must be stbd-to, then turn the boat by hand using long lines ('warping') just as every boatyard does to align boats prior to hauling.

#2. Don't dock.

Some boats do not maneuver well, especially cruising sailboats that often have long keels vs fin keels. Techniques and practice will help, but discretion is key.

Good luck!

Peter

[wingssail]

Originally Posted by chrisr

...full rudder, then full ahead to full astern repeatedly...

Yep, you hear it throughout the marina when one of these guys is using this technique: roaring engines, louder engine as the seemed solution when it is not working is more power on the next application, people running as momentum builds...

We all watch to see how it turns out. I'm just happy his back and forth surges are well away from my parked boat. Too often there is a cracking of fiberglass at the end.

The answer to maneuvering in tight quarters is thinking ahead and gentle application of power

[mvweebles]

Originally Posted by chrisr

i was also shown once how to turn a single prop boat is own length, but you need a hydraulic gearbox...full rudder, then full ahead to full astern repeatedly. never work with a mechanical g/box...

This technique is called "Back & Fill" and for a single engine boat, really only works when a boat is turning in it's preferred direction. The OP's boat has a RH prop (meaning when viewed from behind, the prop turns 'right,' or clockwise in forward). When the prop is placed in reverse, the bottom of the prop drags the boat to port/left - imagine a car tire on pavement. There are a several theories on why prop walk exists, but suffice to say it does - it also exists in forward but is overwhelmed by prop wash. Prop wash has almost no effect in reverse until some sternway is gained so you can leave the helm hard-over while going from forward to reverse. It does not need to be rapid - a brief pause in neutral is fine, and RPMs need only be brought up a few hundred. Important is to build rotational momentum.

Bottom line is the OP's boat can probably make a very tight turn to starboard, but only a wide/lazy turn to port. It is possible to build rotational momentum in the anti-prop-walk direction but substantially more difficult and subject to environmental vagaries such as wind or current that will quickly defeat even well timed and executed turns.

BTW - for those new to Cats, principle of prop-walk is equally useful with twins, though they are ambidextrous. With rare exceptions, the starboard engine has a RH prop, port a LH prop. That means that when the stbd engine is in reverse, the stern will 'walk' left, and vice versa. The first thing most twin-drivers learn is to split the gears - one in forward, the other in reverse, which is great but when docking along a side-tie, often leaves you a couple feet off the dock because the bow rotates away from the dock. Instead of splitting the gears, just place the engine furthest from the dock in reverse, leaving the near-engine in neutral. Gently use throttle/RPMs to feather your speed - your stern will rotate towards the dock without causing the bow to rotate away from the dock. If you develop too much rotational momentum and risk bouncing off your fenders, putting the near-dock engine in reverse will cause opposite prop-walk and slow/reverse your rotation towards the dock. If you need to advance up the dock a bit, putting the near-dock engine in forward will gently move you forward and move your bow off the dock giving you clearance to advance forward.

Peter

[valhalla360]

When looking from above, if the boat doesn't like to turn counter clockwise...don't turn counter clockwise.

Instead as you pull up turn to stb then reverse to port. Prop walk should help you continue to turn the boat clockwise. It might take more than one gear transition to get it all the way turned around. Once turned around, it should be straight forward.

Not always possible but it's usually better to look for a way of doing what the boat wants to do.