[Rhodes22-list] Navigation 101 -- Chapter 1 -- Compasses
Hank
hnw555 at gmail.com
Tue Sep 16 12:29:42 EDT 2008
Bill,
I'm not talking about the difference between true and apparent wind. I'm
talking about compass headings as you go from one tack to another.
Hank
On 9/16/08, Bill Effros <bill at effros.com> wrote:
>
> Hank,
>
> When you are standing in the cockpit of a moving sailboat, how do you
> determine the constant true angle of the wind vs. the relative angle
> your boat is pointing as your boat swings from one tack to the other?
>
> Bill Effros
>
>
>
> Hank wrote:
> > Bill,
> >
> > 110 is the measurement of the arc from a port tack to a starboard
> tack. 45
> > would be half of that for an arc of 90. All of this is assumed that the
> > desired course is dead into the wind and these courses are the best
> possible
> > course that can be made as plotted on a map.
> >
> > Hank
> >
> >
> > On 9/16/08, Bill Effros <bill at effros.com> wrote:
> >
> >> Todd,
> >>
> >> Navigation is still one of my favorite topics.
> >>
> >> OK, let's start while most of us are still on the water.
> >>
> >> There is discussion today about pointing and 45 degrees and 110 degrees.
> >>
> >> These are compass directions.
> >>
> >> How are these numbers derived by the writers?
> >>
> >> (Serious question -- want answers.)
> >>
> >> Throw out your GPS. The GPS measures the direction the device has
> >> traveled, not the direction the boat is pointing.
> >>
> >> How are the writers determining true wind direction?
> >>
> >> How many compasses do you have on board. (You must have at least 2.)
> >>
> >> Fluxgate compasses don't count -- they yield very precise wrong answers.
> >>
> >> Homework Assignment:
> >>
> >> Mount 2 magnetic compasses far enough away from large metal objects and
> >> electronics so they can swing freely. (If one is hand bearing, that's
> >> fine, as long as you can read it in 5 degree increments while the
> >> compass is mounted in a stationary position.
> >>
> >> Point your boat so your main compass is at 0.
> >>
> >> Turn your other compass so it points to exactly 180.
> >>
> >> Now turn your boat so your main compass points to 90. Your other
> >> compass should point to exactly 270. Does it?
> >>
> >> Whether it does, or not, note the readings on both compasses.
> >>
> >> If, after taking a few different readings your compasses are wildly off,
> >> report your results here, and we will go to Chapter 2.
> >>
> >> If the readings remain almost 180 degrees in phase, no matter what
> >> direction you point, make a chart showing all compass readings at 5
> >> degree differences.
> >>
> >> True virgins can't be far behind.
> >>
> >> Bill Effros
> >>
> >> PS -- If anyone gets serious about this, it's a great opportunity to set
> >> and use multiple anchors. If you set 4 and move lines from cleat to
> >> cleat, you can adjust the angle of your boat to the primary compass with
> >> extreme precision, while learning a lot about the setting qualities of
> >> anchors. It doesn't matter if an anchor fails to set properly -- you
> >> are testing the compass, not the anchor.
> >>
> >>
> >>
> >>
> >>
> >> Todd Tavares wrote:
> >>
> >>> Bill, Good to see you back on the list. Didn't you make us all a
> >>> promise? I am still waiting. LOL
> >>> http://www.rhodes22.org/pipermail/rhodes22-list/2005-April/022296.html
> >>> Todd T
> >>>
> >>> ----- Original Message -----
> >>> From: "Bill Effros"
> >>> To: "The Rhodes 22 Email List"
> >>> Subject: Re: [Rhodes22-list] anchoring
> >>> Date: Mon, 15 Sep 2008 14:05:34 -0400
> >>>
> >>>
> >>> Elle,
> >>>
> >>> I was hoping Slim would weigh in on your situation. He has has to
> >>> deal
> >>> with similar problems.
> >>>
> >>> I don't use chain except on rode purchased before I stopped using
> >>> chain.
> >>>
> >>> You can't "set" chain. When it hits the bottom, it just lies there in
> >>> a
> >>> pool. It is exactly the same as dropping the chain into the R-22
> >>> anchor
> >>> locker. It forms a pyramid of chain with the unset anchor dangling
> >>> from
> >>> it on one side, or buried under it, and the rope rode dangling from
> >>> it
> >>> on the other.
> >>>
> >>> I use floating anchor rode directly attached to the anchor. If you
> >>> drop
> >>> a penny overboard it's going to sink until it hits the bottom. If you
> >>> drop a 2 1/2 lb aluminum anchor overboard, it will also sink until it
> >>> hits the bottom.
> >>>
> >>> If you tie a floating rope to that aluminum anchor, you will see no
> >>> rope
> >>> on the surface of the water until the anchor hits the bottom, and the
> >>> excess rope exceeds the straight line angle from where you are
> >>> deploying
> >>> the anchor. At that point you start pulling in excess rope off the
> >>> surface until the angle going into the water is roughly 45 degrees.
> >>> Then just hold onto the line as the wind or your motor drives your
> >>> boat,
> >>> and a good anchor will set itself properly. Cleat the line, and you
> >>> should not be able to move that anchor until you get almost directly
> >>> above it.
> >>>
> >>> I always do this from the stern. I "fish" for the bottom, and "set"
> >>> the
> >>> anchor. Because there is only floating line between me and the anchor
> >>> I
> >>> can "feel" what is going on, and I can see from floating line on the
> >>> surface whether my anchor is truly "set" or if I am just "dragging"
> >>> it.
> >>>
> >>> It's a lot like fishing.
> >>>
> >>> Once set, I walk the line to the bow and cleat it to the bow cleat.
> >>>
> >>> If leaves are truly a problem, and I don't know because I don't
> >>> experience that problem when I anchor, I would use a kellet to bring
> >>> the
> >>> sharp lightweight anchor all the way to the bottom on the all rope
> >>> rode. Then I would experiment with how far to withdraw the kellet in
> >>> order to set the tines of the anchor most reliably. Then I would
> >>> withdraw the kellet completely, and "feel" the set of the anchor in
> >>> the
> >>> way I normally do it. You don't have to "feel" the set many times
> >>> before you know exactly what it is supposed to feel like when it is
> >>> permanently set.
> >>>
> >>> I've wasted a lot of time waiting to see if it would unset, and it
> >>> never
> >>> has.
> >>>
> >>> I don't know of anyone who has tried the "floating the mushroom
> >>> anchor
> >>> into place" theory, but I think it would be fun to try. I know that
> >>> mushroom anchor won't move once properly set, and I also know how to
> >>> use
> >>> a Rhodes 22 to move the anchor if I need to do so.
> >>>
> >>> Like me, I would guess your biggest problem in storm conditions is
> >>> other
> >>> boats, not your ability to keep your boat in a place where it can
> >>> easily
> >>> withstand the elements.
> >>>
> >>> Bill Effros
> >>>
> >>>
> >>>
> >>> elle wrote:
> >>> > HI, Bill, I was hoping that you would also weigh in on this
> >>> > matter...would you give me your recommendation? Again, the bottm
> >>> > is mud IF we can get through the leaves, and the cove is
> >>> > protected; storm surge is often a factor but @20' of chain &
> >>> > @200' of 5/16 rode hopefully is sufficient overkill...
> >>> >
> >>> > Opinion?
> >>> >
> >>> > Thanks, elle
> >>> >
> >>> > We can't change the angle of the wind....but we can adjust our
> >>> sails.
> >>> >
> >>> > 1992 Rhodes 22 Recyc '06 "WaterMusic" (Lady in Red)
> >>> >
> >>> >
> >>> > --- On Mon, 9/15/08, Bill Effros wrote:
> >>> >
> >>> >
> >>> >> From: Bill Effros
> >>> >> Subject: Re: [Rhodes22-list] anchoring
> >>> >> To: "The Rhodes 22 Email List"
> >>> >> Date: Monday, September 15, 2008, 11:47 AM
> >>> >> Peter,
> >>> >>
> >>> >> What difference do think the weight of a boat implies for
> >>> >> the size of the anchor?
> >>> >>
> >>> >> I would imagine windage is the factor.
> >>> >>
> >>> >> No matter what they weigh, all boats float.
> >>> >>
> >>> >> If weight were the factor, the size of a battleship anchor
> >>> >> in proportion to it's weight would be substantially less than the
> >>> >> size anchor most people carry on their Rhodes 22s.
> >>> >>
> >>> >> Someone recently told me that if you take away wind and
> >>> >> current, a 25 lb Fortress anchor will hold an aircraft carrier.
> >>> >>
> >>> >> I've never tried it, though.
> >>> >>
> >>> >> As I've often mentioned, a 2 1/2 lb Fortress Guardian
> >>> >> is my go-to anchor. I set it from the stern, and walk it
> >>> >> forward. Once properly set, it is extremely difficult to
> >>> >> dislodge until you get
> >>> >> almost directly above it. There is never enough windage on my boat
> >>> to
> >>> >> deform the anchor, part the line, challenge the shackle.
> >>> >>
> >>> >> My boat is moored on a 300 lb mushroom anchor as are
> >>> >> virtually all of the boats in the cove where I keep my boat.
> >>> (There are
> >>> >> hundreds.)
> >>> >>
> >>> >> The cove has been hit by strong winds from time to time,
> >>> >> but few move from their moorings. The biggest fear of damage is
> >>> from
> >>> >> other boats coming loose, and debris. The entire fleet swings on
> >>> >> individual anchors. Anchoring
> >>> >> bow and stern puts you broadside to the wind with enormous stress
> >>> on the
> >>> >> anchoring system if the wind is shifting. Mushroom anchors are
> >>> just
> >>> >> as strong in 360 degrees, and you expose your boat to the least
> >>> stress.
> >>> >>
> >>> >> If I had the problem of moving my boat under storm
> >>> >> conditions I would try to rig up an air bag on a mushroom anchor
> >>> so I could
> >>> >> tow it to the place I wanted to set my boat, release the air, and
> >>> sit on
> >>> >> the single mushroom.
> >>> >>
> >>> >> When your boat is floating freely and always facing the
> >>> >> wind there is no chafing problem to speak of, and while the wind
> >>> creates
> >>> >> uncomfortable creaking in all of the boats, the mechanical stress
> >>> on the
> >>> >> components seems negligible. I put a canvas chafe guard on my bow
> >>> >> line where it goes over the edge of the boat (no chock). I have
> >>> not had
> >>> >> to replace the chafe guard in 10 years of use. Most wind damage
> >>> >> around here is done to boats on shore. The wind topples one into
> >>> >> the next. I suspect my boat is far safer
> >>> >> in the water than it is on land.
> >>> >>
> >>> >> Bill Effros
> >>> >>
> >>> >>
> >>> >>
> >>> >> Peter Thorn wrote:
> >>> >>
> >>> >>> elle,
> >>> >>>
> >>> >>> Broad Creek in New Bern, where Blackbeard is located,
> >>> >>>
> >>> >> is the best hurricane
> >>> >>
> >>> >>> hole for miles around. When a surge is expected and
> >>> >>>
> >>> >> boats must leave their
> >>> >>
> >>> >>> docks, everybody around there seems to head for Broad
> >>> >>>
> >>> >> Creek. It's about 15
> >>> >>
> >>> >>> feet of water, then 10' of mud/muck bottom river
> >>> >>>
> >>> >> bottom and then hard clay
> >>> >>
> >>> >>> underneath, according to borings made for the seawall
> >>> >>>
> >>> >> engineering design at
> >>> >>
> >>> >>> our club.
> >>> >>>
> >>> >>> If a storm passes close by, the wind direction can
> >>> >>>
> >>> >> shift greatly during the
> >>> >>
> >>> >>> storm. This adds a different challenge to anchoring.
> >>> >> Some anchors are very
> >>> >>
> >>> >>> good at setting, like Delta plow, others are very good
> >>> >>>
> >>> >> at holding in mud,
> >>> >>
> >>> >>> like the Fortress with the 45 degree fluke settings.
> >>> >> But, if broken loose
> >>> >>
> >>> >>> during a storm while the wind direction is changing, a
> >>> >>>
> >>> >> Fortress will more
> >>> >>
> >>> >>> easily drag and is more difficult to reset.
> >>> >>>
> >>> >>> Different people do different things. One popular
> >>> >>>
> >>> >> anchoring technique is
> >>> >>
> >>> >>> the Bahamian, using two anchors at 45-180 angles.
> >>> >> Other experienced storm
> >>> >>
> >>> >>> survivors here have used two anchors in series to cope
> >>> >>>
> >>> >> with our special
> >>> >>
> >>> >>> bottom conditions. Usually, coming from the direction
> >>> >>>
> >>> >> of the boat, the
> >>> >>
> >>> >>> first anchor is a Delta plow type with the usual nylon
> >>> >>>
> >>> >> rode and chain.
> >>> >>
> >>> >>> Then, they add about 30' of stainless cable and
> >>> >>>
> >>> >> attach a Fortress or
> >>> >>
> >>> >>> Danforth type. The idea is the Delta plow will
> >>> >>>
> >>> >> quickly reset if the
> >>> >>
> >>> >>> direction changes and slow down dragging long enough
> >>> >>>
> >>> >> for the Fortress to
> >>> >>
> >>> >>> also reset, dig in and hold on hard. A friend with a
> >>> >>>
> >>> >> Gulfstar 37 has used
> >>> >>
> >>> >>> this technique for ten years with great success in
> >>> >>>
> >>> >> Broad Creek. His boat is
> >>> >>
> >>> >>> heavy and I know he uses large sizes (not sure how
> >>> >>>
> >>> >> large), but I think the
> >>> >>
> >>> >>> same technique would work for a 3000# R22 with smaller
> >>> >>>
> >>> >> ground tackle.
> >>> >>> Fortunately for Raven, two days before Hannah arrived
> >>> >>>
> >>> >> I just hauled her
> >>> >>
> >>> >>> home. This is a wonderful advantage of a trailerable.
> >>> >>>
> >>> >> But it think it's
> >>> >>
> >>> >>> always a good idea to be prepared for whatever the
> >>> >>>
> >>> >> wind gods send us.
> >>> >>
> >>> >>> May all your storms go the other way,
> >>> >>>
> >>> >>> PT
> >>> >>>
> >>> >>> -----Original Message-----
> >>> >>> From: rhodes22-list-bounces at rhodes22.org
> >>> >>> [mailto:rhodes22-list-bounces at rhodes22.org] On Behalf
> >>> >>>
> >>> >> Of elle
> >>> >>
> >>> >>> Sent: Sunday, September 14, 2008 8:21 PM
> >>> >>> To: The Rhodes 22 Email List
> >>> >>> Subject: Re: [Rhodes22-list] anchoring
> >>> >>>
> >>> >>> Well; what a coincidence.....anchoring is on my mind.
> >>> >>>
> >>> >>> It seems that when Hanna was deciding where to rest
> >>> >>>
> >>> >> her head, we decided to
> >>> >>
> >>> >>> anchor the boats (mine & my neighbor's ) in
> >>> >>>
> >>> >> the creek...which is a
> >>> >>
> >>> >>> well-protected hurrricane hole.
> >>> >>>
> >>> >>> The favored anchoring scheme is two anchors each set
> >>> >>>
> >>> >> at about 45 deg off the
> >>> >>
> >>> >>> bow. I have the (way too light) Danforth-style which
> >>> >>>
> >>> >> comes with the boat &
> >>> >>
> >>> >>> another 21lb Danforth, 200' of rode & @
> >>> >>>
> >>> >> 8-10' of chain.
> >>> >>
> >>> >>> Problem 1....how to anchor from the bow as the furling
> >>> >>>
> >>> >> mechanism is in the
> >>> >>
> >>> >>> way if we go out straight from the bow cleat....or
> >>> >>>
> >>> >> have massive chafing if
> >>> >>
> >>> >>> we run the rode outside of the bow pulpit...boat will
> >>> >>>
> >>> >> then not be
> >>> >>
> >>> >>> head-to-wind.....
> >>> >>>
> >>> >>> Problem 2...this creek has a thick layer of
> >>> >>>
> >>> >> detritus..mainly
> >>> >>
> >>> >>> leaves...coating the bottom....the heavy Danforth
> >>> >>>
> >>> >> would not set w/all the
> >>> >>
> >>> >>> junk, so a new anchor is in my future.
> >>> >>>
> >>> >>> Anyone have any suggestions? I am looking at a Delta
> >>> >>>
> >>> >> as the CQR (my first
> >>> >>
> >>> >>> choice) is 'way too much $$$$$.
> >>> >>>
> >>> >>> We ended up securing one end of the boat to a forward
> >>> >>>
> >>> >> piling and the other
> >>> >>
> >>> >>> to a tree on shore.
> >>> >>>
> >>> >>>
> >>> >>> elle
> >>> >>>
> >>> >>>
> >>> >>>
> >>> >>> We can't change the angle of the wind....but we
> >>> >>>
> >>> >> can adjust our sails.
> >>> >>
> >>> >>> 1992 Rhodes 22 Recyc '06 "WaterMusic"
> >>> >>>
> >>> >> (Lady in Red)
> >>> >>
> >>> >>> --- On Sun, 9/14/08, Michael D. Weisner
> >>> >>>
> >>> >> wrote:
> >>> >>
> >>> >>>
> >>> >>>
> >>> >>>> From: Michael D. Weisner
> >>> >>>>
> >>> >>
> >>> >>
> >>> >>>> Subject: Re: [Rhodes22-list] anchoring
> >>> >>>> To: "The Rhodes 22 Email List"
> >>> >>>>
> >>> >>
> >>> >>
> >>> >>>> Date: Sunday, September 14, 2008, 6:27 PM
> >>> >>>> Paul,
> >>> >>>>
> >>> >>>> We must have beaten this topic to death several
> >>> >>>>
> >>> >> times in
> >>> >>
> >>> >>>> the past. A quick check of the nabble archives under "anchor
> >>> >>>> locker" yielded:
> >>> >>>>
> >>> >>>>
> >>> >>>>
> >>> >>>>
> >>> >>
> >>>
> >>>
> >>
> http://www.nabble.com/anchor-locker---dumb-questions-to18156518.html#a181565
> >>
> >>> >>
> >>> >>> 18
> >>> >>>
> >>> >>>
> >>> >>
> >>>
> http://www.nabble.com/Anchor-rode-spaghetti-to18071799.html#a18144554
> >>> >>
> >>> >>>>
> >>> >>
> >>>
> http://www.nabble.com/Anchor-rode-spaghetti-to18135271.html#a18135271
> >>> >>
> >>> >>>>
> >>> >> http://www.nabble.com/New-Guy-Bill-D.-tp7060395p7069009.html
> >>> >>
> >>> >>>>
> >>> >> http://www.nabble.com/Anchoring---Again-to5113633.html#a5113633
> >>> >>
> >>> >>>>
> >>> >> http://www.nabble.com/Go-To-Anchor-to2383036.html#a2383036
> >>> >>
> >>> >>>> You get the idea. Most of us seem to use a
> >>> >>>>
> >>> >> Rubbermaid
> >>> >>
> >>> >>>> basket in the laz or under a cockpit seat for the stern anchor,
> >>> >>>>
> >>> >> although I
> >>> >>
> >>> >>>> prefer a bag hung on the stern rail. I still use the forward
> >>> locker
> >>> >>>>
> >>> >> for my bow
> >>> >>
> >>> >>>> anchor rode storage. I cleat it to the central foredeck cleat
> >>> >>>>
> >>> >> and pass
> >>> >>
> >>> >>>> it through my bow chocks.
> >>> >>>>
> >>> >>>> Mike
> >>> >>>> s/v Shanghaid'd Summer ('81)
> >>> >>>> Nissequogue River, NY
> >>> >>>>
> >>> >>>> From: "Paul Krawitz"
> >>> >>>> Sent:
> >>> >>>>
> >>> >> Sunday,
> >>> >>
> >>> >>>> September 14, 2008 5:53 PM
> >>> >>>>
> >>> >>>>
> >>> >>>>> How do you guys anchor?
> >>> >>>>>
> >>> >>>>> The forepeak (tiny bow storage area) is an
> >>> >>>> impractical way to store
> >>> >>>>
> >>> >>>>
> >>> >>>>> rode and the opening is to small for my big
> >>> >>>>>
> >>> >> hands to
> >>> >>
> >>> >>>>>
> >>> >>>>>
> >>> >>>> get in there.
> >>> >>>>
> >>> >>>>
> >>> >>>>> I've resorted to storing the rode below
> >>> >>>>>
> >>> >> the
> >>> >>
> >>> >>>>>
> >>> >>>>>
> >>> >>>> cockpit benches, in a
> >>> >>>>
> >>> >>>>
> >>> >>>>> Rubbermaid container, and walking it forward
> >>> >>>>>
> >>> >> and
> >>> >>
> >>> >>>>>
> >>> >>>>>
> >>> >>>> attaching it to the
> >>> >>>>
> >>> >>>>
> >>> >>>>> Danforth anchor handing from the bow pulpit
> >>> >>>>>
> >>> >> when I
> >>> >>
> >>> >>>>>
> >>> >>>>>
> >>> >>>> need to.
> >>> >>>>
> >>> >>>>
> >>> >>>>> Where do you cleat it? The central bow cleat?
> >>> >>>>>
> >>> >>>>> I'm hoping someone has a better
> >>> >>>>>
> >>> >> suggestion.
> >>> >>
> >>> >>>>> Paul K
> >>> >>>>> "Clarity"
> >>> >>>>>
> >>> >>>>>
> >>> >> __________________________________________________
> >>> >>
> >>> >>>>> To subscribe/unsubscribe or for help with
> >>> >>>>>
> >>> >> using the
> >>> >>
> >>> >>>>>
> >>> >>>>>
> >>> >>>> mailing list go to
> >>> >>>>> http://www.rhodes22.org/list
> >>> >>>>>
> >>> >>>>>
> >>> >> __________________________________________________
> >>> >>
> >>> >>>>>
> >>> >>>>>
> >>> >>>> __________________________________________________
> >>> >>>> To subscribe/unsubscribe or for help with using
> >>> >>>>
> >>> >> the mailing
> >>> >>
> >>> >>>> list go to http://www.rhodes22.org/list
> >>> >>>> __________________________________________________
> >>> >>>>
> >>> >>>>
> >>> >>>
> >>> >>> __________________________________________________
> >>> >>> To subscribe/unsubscribe or for help with using the
> >>> >>>
> >>> >> mailing list go to
> >>> >>
> >>> >>> http://www.rhodes22.org/list
> >>> >>> __________________________________________________
> >>> >>>
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> >>> >>>
> >>> >> version of virus signature
> >>> >>
> >>> >>> database 3441 (20080915) __________
> >>> >>>
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> >>> >>> __________________________________________________
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> >>> >>>
> >>> >> mailing list go to http://www.rhodes22.org/list
> >>> >>
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> >>> >>>
> >>> >>>
> >>> >>>
> >>> >> __________________________________________________
> >>> >> To subscribe/unsubscribe or for help with using the mailing
> >>> >> list go to http://www.rhodes22.org/list
> >>> >> __________________________________________________
> >>> >>
> >>> >
> >>> >
> >>> >
> >>> > __________________________________________________
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> >>> > go to http://www.rhodes22.org/list
> >>> > __________________________________________________
> >>> >
> >>> >
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> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >> __________________________________________________
> >> To subscribe/unsubscribe or for help with using the mailing list go to
> >> http://www.rhodes22.org/list
> >> __________________________________________________
> >>
> >>
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> >
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