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Old 21-03-2012, 11:43   #1
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Wind Against Propwalk

I am in a downwind slip for a month. It has two problems: 1) In order to get out I need to reverse the boat out to starboard (My prop walk goes to port) and 2) Because it is a downwind slip the wind will be trying to push me into the other boats on the dock.

The solutions that I have come up with so far are 1) If I reverse out of the slip I can then back down the fairway . . . my boat does not reverse well or straight, or 2) Tie a spring line from the aft cleat on my boat to the dock of a length such that it will allow my bow to clear the port finger before it snubs. When it snubs it will kick my stern to starboard. In the absence of wind this would work great but with a 25 knot wind I am not sure if I will be able to get forward momentum before the wind blows me into the dock.

Can anyone help me with ideas to get out of the dock and not do any damage.
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Old 21-03-2012, 12:49   #2
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Re: Wind against Propwalk

When going astern, at what speed does your rudder have more of an effect at turning your stern to starboard than does your prop wash have at turning your stern to port? There is a speed at which you will start turning to starboard when backing when you rudder is hard over to starboard, with a right hand propeller.

You might want to get underway and experiment with this outside of the marina. Then you can determine if you have enough of a safe distance at your slip for this transition to take place.

You can always try backing and filling. Keep you rudder hard over to starboard, back gently, go ahead aggressively...and just keep doing that. Practice it away from the marina.
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Old 21-03-2012, 12:57   #3
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Re: Wind against Propwalk

Bow thruster?

Would it be possible or make things easier if you backed in to the slip so you could leave bow out first?
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Old 21-03-2012, 12:58   #4
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Re: Wind against Propwalk

Another idea that might work (if you have the room to do it) is to pretend you're coming in to a med moor and go into the slip stern first, dropping your anchor from the bow directly upwind of the slip. Then use your prop, rudder and the wind to settle back into the slip. If you have a small lunch hook you could use that from either the bow or stern. I used this technique (kedging) for years when I kept my boat in an upwind slip and without any motor auxiliary at all. Worked like a champ. Just remember to slack out enough anchor rode when you're through so passing boats don't trip on it.

To get underway, cast off your dock lines and pull in on the kedge, as soon as the kedge is clear of the bottom use your engine to move you down the fairway. If you used an anchor off the bow, you'll be pointing into the wind and can take full advantage of your prop's more efficient direction.

Like I said, I did this for years with a number of boats, and it's basically the same technique I've used when driving ships.
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Old 21-03-2012, 13:20   #5
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Re: Wind against Propwalk

Quote:
Originally Posted by David M View Post
When going astern, at what speed does your rudder have more of an effect at turning your stern to starboard than does your prop wash have at turning your stern to port? There is a speed at which you will start turning to starboard when backing when you rudder is hard over to starboard, with a right hand propeller.

You might want to get underway and experiment with this outside of the marina. Then you can determine if you have enough of a safe distance at your slip for this transition to take place.

You can always try backing and filling. Keep you rudder hard over to starboard, back gently, go ahead aggressively...and just keep doing that. Practice it away from the marina.
It is just under 3 knots before the boat speed over comes the propwalk. I will need to practice some more on backing. I have this tendency to use less power then I need rather then more because I feel that a slower speed will cause less damage. I sometimes go too slow and lose steerage. It is a fine balance and the strong winds off of South San Fran compound my error.

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Originally Posted by svHannabel View Post
Bow thruster?

Would it be possible or make things easier if you backed in to the slip so you could leave bow out first?
I can't back with control until the boat is going almost 3 knots. I am looking at a technique where you steer perpindicular to your slip. Then turn the boat hard to starboard so that the stern swings into the slip. from there give the boat a big shot of reverse to stop forward motion and simultaneously attach a midship line to the furthest forward cleat on the port side. From there leave the boat to idle in reverse and it should propwalk over to the port side. I'd like to practice this a lot in no wind and have the exact right length dockline in place.

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Originally Posted by prof_mariner View Post
Another idea that might work (if you have the room to do it) is to pretend you're coming in to a med moor and go into the slip stern first, dropping your anchor from the bow directly upwind of the slip. Then use your prop, rudder and the wind to settle back into the slip. If you have a small lunch hook you could use that from either the bow or stern. I used this technique (kedging) for years when I kept my boat in an upwind slip and without any motor auxiliary at all. Worked like a champ. Just remember to slack out enough anchor rode when you're through so passing boats don't trip on it.

To get underway, cast off your dock lines and pull in on the kedge, as soon as the kedge is clear of the bottom use your engine to move you down the fairway. If you used an anchor off the bow, you'll be pointing into the wind and can take full advantage of your prop's more efficient direction.

Like I said, I did this for years with a number of boats, and it's basically the same technique I've used when driving ships.
Sounds like a pretty good technique. I may try it.
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Old 21-03-2012, 13:35   #6
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Re: Wind against Propwalk

Charlie

Our boat behaves very much like yours.

If the wind is straight from behind, it actually backs very nicely, the wind keeps the nose from swinging around. The propwalk will set to port, and with the wind holding the nose downwind, the whole boat might walk slowly to port, but by then you hopefully cleared the slip.

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Old 21-03-2012, 14:13   #7
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Re: Wind against Propwalk

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Charlie

Our boat behaves very much like yours.

If the wind is straight from behind, it actually backs very nicely, the wind keeps the nose from swinging around. The propwalk will set to port, and with the wind holding the nose downwind, the whole boat might walk slowly to port, but by then you hopefully cleared the slip.

Dirk
My boat responds the same. The wind will take the bow off if it across it.

Quote:
It is just under 3 knots before the boat speed over comes the propwalk. I will need to practice some more on backing. I have this tendency to use less power then I need rather then more because I feel that a slower speed will cause less damage. I sometimes go too slow and lose steerage. It is a fine balance and the strong winds off of South San Fran compound my error.
You might try more revs for initial motion, then go to neutral w/half right rudder at most. My rudder becomes just effective enough with the prop stopped. If your tail wind is fierce, use more revs and a bit more speed before neutralizing prop.
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Old 21-03-2012, 14:20   #8
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Re: Wind against Propwalk

Have a diagram or image of slip area so we can bet a better idea of specifics?
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Old 21-03-2012, 14:39   #9
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Re: Wind against Propwalk

It depends on a lot of things. My approach would often be: Get the boat moving in reverse at idle for a few feet (helm midships), go to neutral, back into gear for more speed, back to neutral turn helm smoothly to starboard, into gear and hopefully you are steering in reverse to stbd. Once the stern nears the row of boats behind you, Change to forward, turn hard to port and gun it swinging the boat around. etc
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Old 21-03-2012, 23:48   #10
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Re: Wind against Propwalk

great topic, I have a the same issue. This is my first downwind slip and my prop walk would have me back out down the channel (which is a poor option as my boat has a long keel and skeg hung rudder, I have a difficult time of it in reverse). When there is no wind there is no problem, I give some revs in reverse put it in nuetral and make my turn. Last weekend however the prevailing wind was blowing straight astern. I tried the same technique and it was a problem as the wind kept blowing the bow down wind. So I would slowly back up and try turning going forward but no luck, I was crab walking down the channel. Luckily there was an open slip and I pulled into it to clean my shorts before trying again. I sucked up my pride and asked a neighbor to push me off. I think the best option might be locking the wheel in the direction you want about 20% and walking it out, climbing aboard and then putting it in forward and making the turn. I am going to practice this technique with someone at the wheel before trying this alone. Good luck, let us know what works for you, I'll update the thread when I figure it out myself.

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Old 22-03-2012, 00:29   #11
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Re: Wind against Propwalk

A couple of suggestions here:

1) Warp off the dock using either a loop of line off the stern or the midships...which one depends on experimentation.

2) Depending on the size of the boat, run the engine in neutral, center the helm or lock it to favour somewhat where you want the stern to go. Walk the boat out of the slip by pushing on the shrouds or by pulling on the bow line and a midship line. If my little wife can do it with a steel 16 tonner, it can't be that hard. The point is to have the boat moving in the right direction in neutral BEFORE engaging the prop.

If you have a crew, they should be at the bow on the far side to fend off if this isn't working out and you are getting too close.

Once the midship point is nearly at the end of the slip, hop on and get to the throttle. If your helm is tight and you are co-ordinated, work from in front of the wheel. If it saves seconds and does the job, you'll have plenty of time to get behind the wheel when the boat is safely out of the slip and into the lane drifting astern.

Give the boat a short, strong burst of reverse. You are trying to encourage it to continue to curve out of the slip.

Practice backing off a seawall to get the hang of this, and fenders on the far side are your friends.
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Old 25-03-2012, 05:00   #12
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Re: Wind against Propwalk

WHILE THE MOTOR IDLES...I RELEASE ALL THE DOCK LINES WHILE HOLDIND ONTO THE BOAT. THEN I GIVE THE STERN A SHOVE TOWARDS STARBOARD ..HOP ON AND FULL REVERSE......GOOD TO GO
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Old 27-03-2012, 09:50   #13
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Re: Wind Against Propwalk

We had the same problem (except a fin keel! so maybe not exactly the same problem ) in our last slip and came up with a few different solutions.

First, we would usually simply walk the boat back out of the slip, avoiding going into reverse at all... no reverse, no prop walk! You may be a little too large for that, especially if the wind is up, but it would work for us 90% of the time.

Next, if there was just too much wind to get out without applying power, we would suck up our pride and just back the sucker all the way down the fairway. Your keel may give you more trouble in that respect, but it has the benefit of allowing you to apply full power all the way out of the slip so you can get some way on fast... we just added extra fenders and used the finger pier as a pivot point.

Finally, although we never tried this in anger, we had a neighbor who would do it regularly: run a line from the stern to a cleat at the end of the next finger pier to starboard and back. As he reversed out, he would take up on the line, hauling his stern to starboard against the prop walk, and lining himself up for a clean exit. He was thus able to apply enough power to keep himself from drifting back down onto his neighbors transoms but still able to point where he wanted. When he was pointed out, he'd just release the end of the line and haul it back aboard as he went on his merry way.

Good luck!
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Old 06-04-2012, 21:09   #14
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Re: Wind Against Propwalk

I just had the experience of going into the slip in a lot of wind. Below is a copy of the winds at the time I landed from the nearest weather station SFO Airport. I believe that because of the gap at San Bruno Mountain the wind funnels a little stronger in South San Francisco.

04 Apr 5:19 pm PDT 47 35 64 W 20G42 52 15 % 26.49

04 Apr 4:19 pm PDT 48 34 59 W 18G36 55 15 96 9% 26.49

gusts to 36. We were going into a downwind slip. I had to maintain 4 knots of boat speed down the fairway in order to keep the boat from being blown sideways by the wind. Then I needed to make a sharp turn into my slip. In order to accomplish this I turned the rudder hard to port and gave the engine a "goose" ( quick burst of RPM's that pushes water across the rudder and accelerates the turn. ) this caused the boat to accelerate. The wind caused the boat to accelerate. I was headed for the dock at 4 knots and only a boat length away. I let the boat turn about 20 degrees past aligned with the dock and then hit reverse. HARD. With the boat in reverse at full RPM's the boat slowed and squared up to the slip and slowed down. As I was in the right spot I cut the reverse and the boat started to be pused forward into the dock. I had to maintain about 1500 rpm's in order to stay still in my slip until the dock lines were tied on in the right place. I kept my cool but my legs were shaking once we were all tied up.
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Old 06-04-2012, 21:38   #15
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Re: Wind Against Propwalk

Change slips. It will get ugly and might be expensive.
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