[Rhodes22-list] Prop Walk Questions From MJM

Tue Jul 27 09:18:35 EDT 2004

Michael,

While I was getting ready for school this morning, it occurred to me the
article I wrote a couple of years ago for the FAQ page about single line
docking might be helpful in your situation.  The link is:
http://www.geocities.com/blew_skies/docking.html

For your convenience, here's a copy of the article:

____________________________________________________________________________
______________
All boats have a point along both sides, usually just aft of amidships,
wherein a single dock line will cause the boat to stop parallel to a dock.
To find this point, pick a place along the side. It's helpful to use the
sliding cars on the genoa tracks for this purpose. Attach a mooring line to
this point & pull on it from behind. If the bow pulls towards you faster
than the stern, then slide the attachment point aft. If the stern is
favored, then move the attachment point forward. When the boat crabs
sideways towards you, then you have found the approximate sweet spot. The
actual sweet spot will shift slightly when the boat has forward momentum.
However, this approximate location will be sufficiently close to allow you
to go out & try to pull up to a dock with a single line. Try to stop the
boat with a single mooring line using your approximate sweet spot. If the
bow or stern tend to crab towards the dock faster, then adjust the position
of the line fore or aft as before & try again. When you have found the
correct location, you should at least mark it. You may even wish to install
permanent mooring cleats there port & starboard.

With a single mooring line, simply motor up to the dock, slip your loop over
the piling near the end of the dock, & shift into neutral. The mooring line
attached to the sweet spot will snub the boat's forward momentum & the boat
will almost magically "crab" sideways up against the dock. This sideways
crabbing involves a tremendous amount of drag, which uses up the boat's
forward momentum in a matter of inches, thus making it almost impossible to
hit the dock. The boat will stop at a convenient distance away from the dock
for you to go around attaching your bow & stern lines at your leisure. Try
this technique. I guarantee it will make you look like a boat handling
genius!

Roger Pihlaja
S/V Dynamic Equilibrium
08 JUl 2002

____________________________________________________________________________
________________

You might have to slightly modify the above "sweet spot" single mooring line
position to compensate for your boat's tendency to prop walk.  The "sweet
spot" on your boat might also be slightly different on the port vs. the
starboard sides.  But, I guarantee your boat has a "sweet spot" on each
side.

Try this technique.  I bet it will help in your situation!

Good luck!

Roger Pihlaja

S/V Dynamic Equilibrium

----- Original Message -----
From: "Roger Pihlaja" <cen09402 at centurytel.net>
To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
Sent: Tuesday, July 27, 2004 7:30 AM
Subject: [Rhodes22-list] Prop Walk Questions From MJM

> Michael,
>
> I apologize if this subject was covered; but, I'm afraid I haven't been
> paying very close attention.  Who the heck is Sheldon Green & why are you
so
> angry with him?
>
> I don't think building a nozzle around your prop will stop the prop walk
> phenomena.  About the only way to eliminate prop walk is to use
> counterrotating props like on the Volvo-Penta I/O's.
>
> A folding prop will help with the lobster pots while sailing; but, not
under
> power.
>
> A bow thruster will give you the control you want around the dock to
counter
> the prop walk.  This option might cost lest than a skeg or nozzle at the
> stern of the boat + result in more manuevering capability.
>
> You may have to learn to live with the prop walk.  Skippers of single
screw
> boats have lived with this phenomena ever since power boats were invented.
> Remember, there are some docking situations wherein the prop walk can be
> used to advantage to squeeze into & out of a tight space.  Once you get us
ed
> to the prop walk & gain confidence in your understanding of the magnitude
&
> direction of its effects, you may learn to "like it".  Often times,
dealing
> with prop walk is really a matter of avoiding docking situations where it
> makes life difficult.  Learn to plan ahead skipper!
>
> By the way, how does the boat behave while backing up?  Is it hard to
> control?  How does it stop under power?
>
> As far as the lobster pots hanging up on the prop, you might be able to do
> something with stainless steel tubing.  I would think a welded
"guard/skeg"
> could be designed that would keep the lobster pots & lines away from the
> prop without causing too much drag under sail.
>
> Even if you built a skeg to protect the prop & shaft, I would think the
boat
> would still have a very hard time being beached on a tidal mud flat.  The
> mud will get into your cutlass bearing & prop shaft packing gland, causing
> all sorts of premature wear.
>
> Boy inboard diesel engine, wheel steering, standing headroom in the main
> cabin...you have really graduated into an entirely different league in
> boating haven't you?
>
> I'm glad Karin likes the boat.  You two will surely have a lot of good
times
> with it.
>
> Roger Pihlaja
> S/V Dynamic Equilibrium
>
> ----- Original Message -----
> From: "Michael Meltzer" <mjm at michaelmeltzer.com>
> To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
> Sent: Monday, July 26, 2004 9:26 PM
> Subject: Re: [Rhodes22-list] well here is my lack of photo skill
>
>
> > I have to watch out, it to easily to pack rat :-) The boat pretty good
> about storage, room under all the seat, the boat pretty
> > loaded at this point with the "cluttered" feel(yet).
> > Very stiff boat, more beam, 1200 pounds 6 feet down, light weight decks
> from vacuumed bagging, and less sail area than the Rhodes.
> > added in the 300+ pound for the diesel takes allot to knock her down.
Had
> her out 10-12 knots gusting to 15, could not get more than
> > 15 digress and was doing haul speed on all points. She points high. For
> light air I going to have to use the cursing spinnaker.
> > Getting their. Karin Likes it. I still need more time to know
her(docking
> has been a laugh, or is that people laughing at me, And I
> > do not let people to close to see the sail shape :-)
> >
> > I got a question if you are in the mood.
> > 1)The prop walk is killing me.
> > 2)both the keel and rudder come up, so my prop and prop shaft are even
> with if not lower that the rest, boat might reset on it dried
> > out
> > 3)Lines from lobster pots are all over the place.
> > 4)the prop is just "hanging out" like egg beater, not skeg of than 3
foot
> shadow from the keel
> >
> > I been thinking about a ring around the prop, like a "kort nozzle", thin
> head on profile and basically round for low water
> > resistances.   The idea: it would be able hold the weight of the boat,
> overbuild for impact, kill the prop walk and act as a gaur.
> > Might even be able to use a vertical shaft slaved to the wheel rotate
for
> some low speed vector thrust.
> >
> > Any thoughts?, I have about 2-3 inch of clearance to the underside from
> the prop. Do I risks blowing out the bottom of the boat in a
> > impact? The area in play is a compound curve, any thoughts front and
> backing plates cover area(1 inch vacuumed bag hull). bonding
> > problems? to keep the vertical shaft packing above the waterline would
an
> 18 inch tube in tube work? Any ideas how to get it made?,
> > Not asking for details, I not "commented" to the idea, but some "back of
> the envelope" would be appraised. Thier seem alot of plues
> > here, the fact no one is doing it might mean I missing somethimg.
> >
> > MJM
> >
> >
> >
> >
> >
> >
> > ----- Original Message -----
> > From: "Roger Pihlaja" <cen09402 at centurytel.net>
> > To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
> > Sent: Monday, July 26, 2004 7:48 AM
> > Subject: Re: [Rhodes22-list] well here is my lack of photo skill
> >
> >
> > > Michael,
> > >
> > > Thank-you for posting my Crystal Mountain pictures.
> > >
> > > Your photos aren't bad.  How did you manage to get photos from about
10
> > > months in the future, 5/16/2005? :)  Do you really own this boat or is
> this
> > > the future?
> > >
> > > Your boat has very classic lines.  She's a real beauty!  You should
have
> a
> > > lot of fun with this one.
> > >
> > > Boy, you could seriously lose something in that cavernous quarter
> > > berth/storage space under the cockpit, couldn't you?
> > >
> > > So, how does she sail?
> > >
> > > Roger Pihlaja
> > > S/V Dynamic Equilibrium
> > >
> > > ----- Original Message -----
> > > From: "Michael Meltzer" <mjm at michaelmeltzer.com>
> > > To: <rhodes22-list at rhodes22.org>
> > > Sent: Monday, July 26, 2004 12:02 AM
> > > Subject: [Rhodes22-list] well here is my lack of photo skill
> > >
> > >
> > > >
> > > > Your files are attached and ready to send with this message.
> > > >
> > >
> > >
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> > > > __________________________________________________
> > > > Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
> > >
> > >
> > > __________________________________________________
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> > >
> >
> > __________________________________________________
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> >
> >
>
>
> __________________________________________________
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>
>