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Dock-O-Matic mark II

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delliottg
Former Mainsheet C250 Tech Editor

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USA
4479 Posts

Initially Posted - 05/02/2009 : 22:01:36

We've successfully used the Nauti-dock-o-matic on our boat, but not without problems. We had a problem with the loop dropping off of the boat hook, and since we basically get exactly one chance to get it right, I've reworked the design a bit:

Basically it's the same, but I made a bowline in the bight after winding the line around itself to make it stiffer, then the loop is to hold the boat hook. We haven't tried it yet, but we went through several iterations today until Rita thought it was workable.

We moved into our new slip on Friday, and completely blew the first approach, coming uncomfortably close to our neighbor both to our port and to the stern. The wind was blowing downstream, the tide was on it's way out, and the current was heading, well, downstream. We made it into the slip the next time, but the loop dropped off the hook, and we ended up fending off of our new neighbor until we got tied up. We sat and thought about it for a while afterwards and this is what we came up with.

David
C-250 Mainsheet Editor

Sirius Lepak
1997 C-250 WK TR #271 --Seattle area Port Captain --

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Steve Blackburn
Master Marine Consultant

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Canada
1091 Posts

Response Posted - 05/02/2009 : 23:54:32

I can imagine how difficult it must be to dock with a transversal current. I bet you don`t have too many chances at getting it right.

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islander
Master Marine Consultant

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USA
3992 Posts

Response Posted - 05/03/2009 : 07:51:22

You can also try sleeving the large loop with clear vinyl hose. This will keep the loop open preventing it from collapsing.

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jerlim
Master Marine Consultant

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USA
1484 Posts

Response Posted - 05/03/2009 : 07:59:58

I think you've got a winner!

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Nautiduck
Master Marine Consultant

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USA
3704 Posts

Response Posted - 05/03/2009 : 08:09:23

Patent infringement! You'll be hearing from Nautiduck Corporation's attorneys.

We no longer use the boat hook. Pat just leans over and drops the loop on the cleat as I slowly enter the slip. Much easier. Of course we have no current or tide to deal with and have a straight shot into the slip. We use the cleat at the end of the slip.

For use of a boat hook I really like what you have done. Holding the line without that added little loop is tough, especially in a strong wind. Nice job.

We also have a snubber on the line to help absorb any impact on the line.

I suggest we avoid use of the lawyers by having you send us 10% of all profits from your adaptation.

Edited by - Nautiduck on 05/03/2009 08:18:20

islander
Master Marine Consultant

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USA
3992 Posts

Response Posted - 05/03/2009 : 08:25:02

Often when I'm alone I will use the single line method. Its very easy and works for cleats, posts, pilings etc. This 'how to' video shows how its done. Click on Docking Solo. http://www.latsandatts.tv/how-to.php

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Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 05/03/2009 : 08:44:03

I like the new "generation"--might make one for foreign docks. But it looks more like a sort of double cow-hitch than a bowline... (?)

Cross-currents are a pain. In my pot, cross-winds are even worse (pretty long wind-fetch, lotsa windage forward, and hardly any keel). Are you able to maneuver so you're heading up-current and then turn into the slip? I often do a 180 before entering the slip so I can hold the bow slightly into the current/wind, counteracting the push until I'm adequately into the slip. But every now and then you'll hear me crank up in reverse as I bail out and start over.

Also, in my own slip, I keep the "docking springline" on the dock cleat and positioned so I can pick it up and drop it on a midship cleat. It seems like there's less chance of fumbling that way.

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delliottg
Former Mainsheet C250 Tech Editor

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USA
4479 Posts

Response Posted - 05/03/2009 : 09:06:47

Randy,
I'll have my people talk to your people. It would be nice to just lean over and drop it on a cleat, but our docking situations are always dynamic, the current is always trying to carry us downstream, so once we commit to the turn, there's virtually no turning back, and the situation is in play. If we miss the cleat, we're fending off, there's no second chance. So we have to have the extra length of the pole to be able to reach the dock.

Dave,
It's a bowline on the bight, my original idea was to have two loops to double our chances of snagging the cleat, plus the loop at the top, but realized it wasn't going to be all that helpful. So after consulting with Rita for a bit about it, I tried winding the legs together before tying the knot to stiffen it. It took about three tries to get it "right", as in tight enough (I hope) to stay stiff while dangling, but spill into a loop when pulled on.

In our new slip, we have half the fairway to recover in, and I might start spinning the boat around to point upstream as you said, but without the hard/soft link (still haven't come up with a workable solution for my rudder/mount/OB situation yet), doing the 180 will be tricky, especially if the wind is piped up.

Islander,
If it doesn't stay open like we want, I'll probably do the vinyl hose bit, or maybe some small PVC pipe cut into 1" lengths like big beads to make it stay open. We have split loom on the one we've been using which I made up with nice eyes, but it simply doesn't work all that well. Anything to reduce the stress of coming in helps.

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Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 05/03/2009 : 09:52:34

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by delliottg
 ...I might start spinning the boat around to point upstream as you said, but without the hard/soft link (still haven't come up with a workable solution for my rudder/mount/OB situation yet), doing the 180 will be tricky...<hr height="1" noshade id="quote"></blockquote id="quote">Keep in mind that the boat will pivot much more tightly turning to port than to starboard (in forward gear), due to the prop-walk effect that pushes the stern to starboard. Meanwhile, remember not to push the tiller hard-over too quickly--you'll almost do better if you let it go free and just turn with the engine (except in reverse, where that doesn't work).

Conversely, sometimes I pivot the boat clockwise (bow to starboard) by veering to starboard and then going into and staying in reverse, which pulls the stern to port. I start that maneuver somewhat upwind of my slip, so I'm pivoting as I drift down and past it. When turned almost 180, I go back into forward gear and approach the slip upwind. Timed just right, it's almost like a 270-degree turn. I just find up-wind/current to be easier to control and more forgiving.

Edited by - Dave Bristle on 05/03/2009 10:02:50

Stu Jackson C34
Admiral

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844 Posts

Response Posted - 05/03/2009 : 12:56:45

Scott, that video was fine. One thing: don't use a stanchion for the midships spring line on the boat. Install a cleat amidships, either ono the deck or on the track. Boy, will he end up having a leaking stanchion. He'll learn...

See: http://c34.org/bbs/index.php/topic,4921.0.html

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islander
Master Marine Consultant

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USA
3992 Posts

Response Posted - 05/03/2009 : 13:19:24

Yes, My mistake. Actually I forgot to say that I tie to the front cleat, Run the line outside the stanchions back to the cockpit and toss the line from there. Sorry.

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dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 05/03/2009 : 14:38:44

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Dave Bristle
 Also, in my own slip, I keep the "docking springline" on the dock cleat and positioned so I can pick it up and drop it on a midship cleat. It seems like there's less chance of fumbling that way.
<hr height="1" noshade id="quote"></blockquote id="quote">

Like Dave, as a singlehanded sailor, I find it much easier to pick up (with my hand) my already affixed to the dock springline, aka brakeline, which is then simply placed over the winch.

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delliottg
Former Mainsheet C250 Tech Editor

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USA
4479 Posts

Response Posted - 05/03/2009 : 19:16:43

I agree, the problem with doing the pirouette right by my slip is the giant Bayliner on the other side of the fairway. If I wait till after he's gone astern, I have a hole in the line of pots where I can spin.

I'm not so sure there's much prop walk with an OB, my understanding of prop walk is the it's caused primarily by the angle the blade meets the water due to the shaft. With a nearly vertical shaft (and hence horizontal prop), prop walk should be about the same in either direction. In any case, having the rudder linked made a huge difference with my original OB, I really need to come up with a solution for this one.

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Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 05/03/2009 : 20:10:09

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by delliottg
 I'm not so sure there's much prop walk with an OB, my understanding of prop walk is the it's caused primarily by the angle the blade meets the water due to the shaft. With a nearly vertical shaft (and hence horizontal prop), prop walk should be about the same in either direction.<hr height="1" noshade id="quote"></blockquote id="quote">Nope. Prop walk is a complicated thing, but it's due to the greater sideways force the blades have at the bottom of the rotation than the top, due to the anticavitation plate's and lower unit's effect on the flow. It's sorta like a paddle wheel, even though the majority of the force is aft (or, in reverse, forward), some residual is sideways. You can test this anywhere--you'll find, in forward gear, you and turn more sharply to port, and in reverse, you can turn more sharply to port. The place you notice this is around a dock where the radius for tight turns can become very clear.

BTW, the way to minimize this effect, if you want to turn sharply to starboard, is to use short bursts of throttle to generate momentary thrust, and then idle back and use the rudder to steer you without having the prop-walk working against you.

Edited by - Dave Bristle on 05/03/2009 20:14:46

delliottg
Former Mainsheet C250 Tech Editor

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USA
4479 Posts

Response Posted - 05/03/2009 : 21:17:52

Well, the new dock line has passed it's first test with flying colors. I met up with Steve (Piseas) and his brother Anthony today & we took a sail out to Blake Island & back. We snagged the cleat first time with no drama. So now it's time to clean it up and make it ready for use.

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JohnP
Master Marine Consultant

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1519 Posts

Response Posted - 05/04/2009 : 07:07:21

Duck can patent his device, but now you should copyright your modified bowline-on-a-bight, the "Sirius Hitch". It will no doubt go down in history as an indispensible knot for the single-handed sailor! Just send your picture in to Elbert S. Maloney, editor of Chapman's. Eventually the spelling will change, of course, like in all folklore, but we'll know the true story!

And if you want stiff dock lines, just soak your brand new green line in the briny deep a few times and let dry, and it will become as stiff as a board, and maybe 2% weaker from the salt crystals within the weave. Some of my dock lines were really stiff until I washed them last winter.

I like the Sirius Hitch.

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Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 05/04/2009 : 09:05:21

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by JohnP
 ...And if you want stiff dock lines, just soak your brand new green line in the briny deep a few times and let dry, and it will become as stiff as a board...<hr height="1" noshade id="quote"></blockquote id="quote">I dipped the tails of my docklines in the saltwater before making a Flemish coil on the dock--now the coil is like a flat rock. (Ya, ya, I know--you're not supposed to Flemish docklines... Well, a pre-emptive "baloney".

)

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