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Boats hit rocks all the time, often snapping off deep keels.

Feb 11, 2017
387
C&C 27 MkII Ottawa
Jackdaw, I made a bold statement, you called me out on it. I explained myself, you and others pointed to errors in my knowledge-base, I argued back, corrected an assumption based on your information and elaborated on my idea. I remain sceptical about the impossibilities of my thoughts, but I respect your position. If we have the technology to measure a 5mm change in a distant planet's orbit, I can't imagine we can't put instruments on a boat that can find its position within feet of a dangerous and known rock without satellite help.
There is, of course, a point at which this discussion needs to wind down and I think you are wise to be sensitive to it at this time. Another of my many failing is my inability to recognise those times before it is too late.
I hope you know I hold your opinions in high regard. I just don't agree with you on this. :meh:

- Will (Dragonfly)
Will, this is an interesting discussion and as Jackdaw says, the devil is in the details. Your idea of using electronically assisted celestial navigation is not new. Satellites, Space Shuttles and even long range missiles have used star trackers for years. I worked for a company that developed them (search CALTRAC Star Tracker). You need a decent view of the sky and a good timing reference and then the proper celestial tables. The trouble with doing that on earth is a lot of stuff gets in the way. Pitching and rolling in a seaway would add challenges but the real problem would be getting a clear view of the sky 24/7. You're making the assumption you can use sensors to detect the very faint radiation emanating from distant stars through overcast or in daylight. The problem with that is mostly to do with antenna gain. The interactions of the RF spectrum through the earth's atmosphere changes quite a bit over the range from DC to light as do the characteristics of the receiving antennas. Star Trackers use radiation near to the visible spectrum. The receiving sensors for these are reasonably small with fairly high gain. When you extrapolate that down to the part of the spectrum that can make it through cloud cover the frequency drops and the wavelength gets longer but the amplitude is quite small meaning you need massive antennas to pick it up. You also need very high gain to pinpoint the source which also means large. As mentioned above, this kind of kit needs to be VERY stable, bolted to bedrock. Even then, trying to discern the radiation from one star to the next would be a challenge and would take some time, scanning some area of the sky with your high gain (narrow field of view) antenna.
GPS was designed to get around these limitations by providing a known pseudo-random code that the receiver can pick out of the noise. This means you can use a cheap, small, portable, low gain antenna to pick up the signal. In addition, there are some GPS satellites which transmit WAAS which includes ephimeric and ionospheric delay corrections to improve accuracy which stars will never be able to do. The GPS satellites even provides the timing reference for you!
In essence, it is possible to do what you are proposing (in fact it is already being done) but not with the reliability and accuracy of GPS for the given cost and portability using technology available today.
 
Oct 19, 2017
4,908
O'Day 19 Littleton, NH
I worked for a company that developed them (search CALTRAC Star Tracker). You need a decent view of the sky and a good timing reference and then the proper celestial tables. ...
Thank you DArcy, Those are some facts I can understand. I did not mean to derail this discussion like I did. The flurry of posts around a statement I put out casually, though I felt had merit, got out of hand. Thank you everyone for your patience:pray:
And now, back to our regularly scheduled program.

-Will (Dragonfly)
 
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Oct 22, 2014
9,890
CAL 35 Cruiser Portland OR, moored EVERETT WA
Took two years to plan and all gone in 2 days of cruising. Bad plan.
 
Oct 19, 2017
4,908
O'Day 19 Littleton, NH
So tragic.

Shows the value of a good boat survey.
Probably hit another boat that was bought without a survey because there's nothing but sand on that coast.

Now their life is much simpler.

But really, what a sad story.

- Will (Dragonfly)
 
Nov 8, 2010
10,550
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
The keel of that boat did not break off. They ran aground on a sandbar and were swamped because they did not know how to prevent that. They lost everything because they spent their time gathering the dogs favorite toys. Now they are going to gofundme to raise cash to recover the 48 year old boat.

AF5C3BAA-B036-46C6-90E9-45F902983C19.jpeg


People that know me know I believe that any sussessful voyage requires some combination of three things; skill, preparation and luck. They are way heavy on the last one.
 
Oct 19, 2017
4,908
O'Day 19 Littleton, NH
any sussessful voyage requires some combination of three things; skill, preparation and luck. They are way heavy on the last one.
Are you saying there are a limited number of points we get and if we use them all in one category we don't have them to use in the others? Sounds a little like AD&D. I like it:thumbup:

- Will (Dragonfly)
 

TomY

Alden Forum Moderator
Jun 22, 2004
1,810
Alden 38' Challenger yawl Rockport Harbor
the anti fowling paint sure looks nice
It does, curiously.

It's inevitable new sailors (non sailors), especially without a CP for a fighting chance, will run aground down there in no time (I'm surprised they got that far).

Currents are pretty fierce down south and will sweep you out of channels quickly. Not the easiest navigation to start your sailing life.

Usually new sailors with small boats, especially young people (and adrenaline), get off. After a few groundings, they start to get the hang of it, as long as the boat is stout enough to hold up (I doubt they lost that keel).
 
Oct 19, 2017
4,908
O'Day 19 Littleton, NH
the anti fowling paint sure looks nice
I don't think it looks that good. It looks new, but it doesn't look well applied, even or thick enough. Are there perhaps craftsmanship issues to consider?
That picture is not of a sailboat trying to right itself. What model was their boat?

- Will (Dragonfly)
 

TomY

Alden Forum Moderator
Jun 22, 2004
1,810
Alden 38' Challenger yawl Rockport Harbor
Maybe I’m misinterpreting this image, but it looks as though the lower part of the keel is gone and only the stub remains.
Yep, it does. :) Looking at Saildata, the Columbia 28 has a fin keel. But it's long at the hull attachment. They don't usually come off too easily. Sandbars are pretty forgiving on impact.
 
Oct 19, 2017
4,908
O'Day 19 Littleton, NH
I think you can actually see the keel laying on the bottom under the boat, not attached.

- Will (Dragonfly)
 

Tod

Dec 30, 2010
82
Montgomery 17 trailered
The anti fouling paint looks good because they had just refit the boat (no doubt including having just painted the bottom) two days prior.
 
Feb 11, 2017
387
C&C 27 MkII Ottawa
People that know me know I believe that any sussessful voyage requires some combination of three things; skill, preparation and luck. They are way heavy on the last one.
I don't usually like to be an armchair quarter back but this one is screaming for it. These guys were sorely lacking in skill, probably not well prepared and it seems like their luck was a little thin as well.
Here is a link to another article where they say "It was about 8:45 p.m. when they sailed into a new port, navigating a channel they had never sailed before, in the dark, fog rolling in."
http://www.tampabay.com/news/Sunken-dreams-Everything-they-own-is-at-the-bottom-of-John-s-Pass_165308644
So they were approaching a tricky, unknown entrance in the dark, with enough boat speed to shear the keel off. Perhaps a basic learn to cruise/navigate course would have been a good idea before investing all their money in a boat and casting off.
Another quote from the article "They had no sailing experience. His father helped them sail along the Gulf Coast, from Alabama to Panama City. That’s how the couple learned how to sail." I hope the father feels at least a little guilty for helping them with this without proper preparation. I'm all for people following their dreams, and I admire this couple for getting out there and doing it, I just hope they now realize how little they know before trying something like this again.
 
Jun 3, 2004
234
Hunter 336 Pensacola
Looking at this image, and compare it to the charts for John’s pass... something is missing... where is green can 3? I believe that nun is #2, as #4 is only 350’ from green can 5, and if it’s #4 they are aground in the dead center of the channel. I know pictures can be misleading, but if green can 3 is missing is easy to see how anyone could mistake 5 for 3 and run hard into the shoal.
 

Attachments

Jun 3, 2004
234
Hunter 336 Pensacola
Well, after studying the image a bit more, I think it is red nun #4... but then they are mid channel in 3’...
 
Mar 26, 2017
32
Irwin 38 Palacios
Our first trip across Matagora bay in our then newly purchased Irwin 37 was a disaster. We Ran late leaving port, took longer tacking that we thought, ended up pulling into an unfamiliar port after dark. chart plotter bit the dust 30 minutes from port. our Fin keel Hit a underwater concrete obstruction motoring in at about six knots. Boat bounced over the obstruction and rudder struck and stopped boat dead. go off with a big dent and scrape on the keel, a broken rudder and a badly bruised nephew. My nephew and I laugh now but when we hit rocks that night it was a tossup whether we would ever sail again. We decided to consider it a wake up call, showing us just how much we had to learn...