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Old 14-06-2018, 11:38   #1
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Affect of wind on using prop-walk to spin boat

I have a Tashiba-31, which is a full keel boat that I'm learning to sail. I've practiced using prop walk to spin the boat and can pretty much spin her in almost her own length - as long as it's calm.

I'm wondering what affect wind speed is going to have on being able to turn the boat around in a fairway and at what wind speed should I not even attempt it.

I know that only experience will give me the full answer, but until I'm able to develop that experience I would rather not put myself and the boat into a position best reserved for experts.

For example. I'm currently in my slip bow first. To leave I need to backout and proceed down the fairway to starboard. Prop walk is going to push my stern to starboard. The space between docks is narrow, so instead of trying fight the prop walk and turn out of the dock I generally will backup to the intersection, then spin the boat in order to proceed forward down the fairway.


Yes, I could use a springline to help with making the turn as I back out of the slip and I'm working on that.


What I'm asking is - in generally - what amount of wind and from what direction would be enough to make using a springline the only option as I would not be able to spin the boat otherwise.
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Old 14-06-2018, 11:54   #2
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Re: Affect of wind on using prop-walk to spin boat

Have you considered trying maneuvers outside the marina in different wind conditions so YOU can answer your own question?
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Old 14-06-2018, 12:13   #3
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Re: Affect of wind on using prop-walk to spin boat

Stu's right. Every boat is different, and even every wind is different in terms of how it funnels through a marina.

Generally speaking, the issue is getting your bow around, so at the point where the wind is off your beam or you are generally broadside you may find yourself slowly crabbing to leeward instead of being able to bring her around. But every boat is different.

One tactic to keep in mind; keep your rudder hard over to the side opposite your prop walk. Prop walk will pull your stern to the side with the rudder doing little, but when in forward your rudder is directing flow to turn the boat. I see a lot of people furiously spinning the wheel when doing this maneuver. It's not necessary on anything without a spade rudder.
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Old 14-06-2018, 13:56   #4
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Re: Affect of wind on using prop-walk to spin boat

Quote:
Originally Posted by Suijin View Post
Stu's right. Every boat is different, and even every wind is different in terms of how it funnels through a marina.

Generally speaking, the issue is getting your bow around, ...




Mine is a fin keel and the bow moves very quickly in the wind. As a full keel boat yours won't move as quickly. It is a matter of practise and getting to know the boat's response, obviously in a location where you won't cause any damage. I reverse out of my slip and down the fairway using the propwalk to make my turn - my pw and the turn is to port. The summer winds are invariably 10-20 from the NW, and I'm backing into it initially. As Suijin says, at a higher wind speed the boat crabs down the fairway and you just make a helm adjustment.


Your boat obviously handles well in reverse which is a bonus.
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Old 15-06-2018, 09:25   #5
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Re: Affect of wind on using prop-walk to spin boat

Backing up is generally not considered as quickly as it should be.

I ran a Hans Christian 43 years ago and in reverse she was a dream.

Try to swing her bow around with 10-15 blowing, not so easy.

Our current fin keel mono the same. A good breeze and the bow is not going to go through the wind easily. Backing up is again the trick.

Stu is correct, practice ;-)
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Old 15-06-2018, 09:40   #6
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Re: Affect of wind on using prop-walk to spin boat

Prop walk is something of a misnomer. Prop walk is the effect you get just from the prop turning. It can be significant on high power motor boats with large twin props that both turn the same way and will kick the stern when throttle is applied. It is usually unnoticeable on a sailboat.
What you are seeing is due to the prop being directly behind the keel. If you tie alongside, put the engine in reverse and watch over the side you will see that most of the wash is on one side. That makes her always want to turn the other way in reverse! If you then but her is ahead and turn the rudder 45deg you will also see ti deflect most of the prop wash sideways off the rudder. You can use this to turn her by giving sharp burst on the throttle to kick the stern around followed by low revs ASTERN to stop you building up speed.
To find out what the wind does find some flat water with about 10-12kn of wind. Park beam on and see what happens. Some boats turn bow to wind, most turn stern to wind. If it is really bad you can play around using a storm jib on the bow or backstay to improve the balance.
Last one is learn to use lines. If it is windy the safest way to more in a marina is to find a berth to the windward side, come up to the end of the finger and get a bow line around it then pull her into the berth using the lines. You can also use a tripping line to turn the stern when you exit.

Worth having a look at some older sailing manuals, these where standard maneuvering tools in the days when lots of boats had small engines and big keels
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