JohnHuth

There's a possible solution, except might be difficult to read unless large enough scale. Kinkos and Staples won't print it out for you....UNLESS.... you're able to clip away the fine print, saying where it came from. I've tried to get large printouts of topos from Kinkos and Staples and they refused, but when I altered them and clipped out the USGS information, they were willing.

If we could, can we go with the chart of Boston Harbor that I indicated in my previous message? If we can get a few other people to bring them, we can go with this for any exercises. Thanks! John

I've paddled through there a couple of times. It's a beautiful area. There were a lot of moose in Fourth Machias last time I was there. I'd recommend taking a day and exploring the swamp and drainage creek in Fourth Machias - it's to the east close to the outlet - easy to find from a topo. Going down the upper stretches of the Machias from Fourth Machias and be "scratchy" (i.e. low water). There was a huge amount of beaver activity in and around Third Machias last time I was there. The activity was so large that it really altered the landscape, so that the topos were no longer accurate. Pretty amazing. The connecting creek out of Third Machias into Wabussus was almost dry as there was a giant beaver dam near there - it had flooded much of the forest upstream of it. Impressive creatures! You have to nose around to find the connecting stream and then be willing to drag. Maybe that's changed - I don't know if the beavers are still there - that was maybe 6 years ago. The portage into Fourth Machias from Sysladopsis Lake is kind of long, but doable, and definitely worth it to get to Fourth Machias.

Topics: attendance and choice of chart Excellent - we have three sets now. Can I get a rough census of people who are coming, so we can figure out the size of groups working together? I realize plans can change at the last minute, but it's good to find out who is intending to go. Here's another question - we should all have common charts to work from. My inclination is to go with a chart that most people might find handy. One is a 1:25000 of Boston Harbor - you can preview it here: http://www.charts.noaa.gov/OnLineViewer/13270.shtml It's chart 13270 Another is the approach to Southwest Harbor http://www.charts.noaa.gov/OnLineViewer/13321.shtml It's chart 13321 Charts are available typically as print-on-demand by places like Charts Online - (nautical charts.com) Here's a link to the SW Harbor chart from Charts Online: http://nauticalcharts.com/search_details.php?ID=18603&SearchField=13321 Boston Harbor http://nauticalcharts.com/search_details.php?ID=19008&SearchField=13270 If we're breaking up into teams, we don't necessarily need one chart per person. Note that there aren't any large tidal currents for these areas. I may try to choose a smaller area for printout where there are significant tidal currents.

Iceland is magnificent. I agree with Chuck that you should plan on visiting parts of the island. However, one place I personally stay away from is the so-called Blue Lagoon. It is advertised as a geothermal spa, but here's what it is: There's a geothermal power plant there - they take sea water and dump it into a volcanic fissure, creating steam to power generators. What's left over is a kind of gooey water that has a bunch of dead cyanobacteria (aka blue-green algae), which they then toss out into holding ponds. The holding ponds of the dead cyanobacteria is the Blue Lagoon. Supposedly dead cyanobacteria are good for the skin, but I could not bring myself to put the goop on my skin, which is also sold in little jars in the duty free shops in the airport. Go see the magnificent waterfalls, the huge glaciers. There's a place called Thingvaleer (trying to approximate the way it's pronounced - the "Th" in Icelandic looks like a "P") - it's where yearly councils were held at a large rift valley - very impressive.

Actually, Dava did something of a disservice to the astronomers in Longitude. The idea of using a clock for measuring longitude was first suggested by Gemma Frisius in the 16th century. He would certainly be called a scientist, I think. The idea was later picked up by Christiaan Huygens, who we could definitely call an astronomer. He developed the grandfather clock, which is quite accurate. The problem is that it could be used on shipboard, because of the jolts and accelerations - in addition to heating issues. Harrison solved the problems of acceleration and heating issues with some novel concepts, like two weights on springs that swung back and forth - but these, in part, were inspired by Huygens earlier work. Now, on the flip side of the coin, astronomers had another interest in the moon. It was the so-called "three body problem". Although Newton's laws accounted for universal gravity, the actual calculation of the lunar orbit was a real nightmare, as the motions of the earth, sun, and moon all come into play. It took many years until the proper mathematical treatment, called perturbation theory, was advanced enough to calculate the lunar orbit. In fact, the so-called lunar method also worked for finding longitude once the orbit was properly described. The calculations as developed by Nevil Maskelyne were kind of clunky, so it took Salem's own Nathaniel Bowditch to simplify them so that people on ship-board could use them. Early on, chronometers were incredibly expensive and out of the price range for normal merchant vessels, so the American whaling fleets employed lunar sightings to find longitude well until about 1850 and even beyond that. James Cook, Lewis and Clark, and many other explorers used the lunar method, not chronometers for longitude. Ultimately the price did come down for nautical chronometers to be used widely, but that wasn't until about 1850 or 1860

A couple of quick items about the Shackleton journey - it was a Norwegian whaling station. Also when they were crossing South Georgia, there was a strange experience where two of them felt like there was a fourth person walking with them, not three. TS Eliot used the idea in the Waste Land - here's the stanza: Who is the third who walks always beside you?When I count, there are only you and I togetherBut when I look ahead up the white roadThere is always another one walking beside youGliding wrapt in a brown mantle, hoodedI do not know whether a man or a woman—But who is that on the other side of you? Here was what Eliot wrote about the passage: The following lines were stimulated by the account of one of the Antarctic expeditions (I forget which, but I think one of Shackleton's): it was related that the party of explorers, at the extremity of their strength, had the constant delusion that there was one more member than could actually be counted. From Huntsford's book on Shackleton: I know that during that long and racking march of thirty-six hours over the unnamed mountains and glaciers of South Georgia, it seemed to me often that we were four, not three.

The navigational hero of that open boat voyage to South Georgia was Frank Worsley - amazing feat - here's a link to the Wikipedia article on him: http://en.wikipedia.org/wiki/Frank_Worsley The Southern Ocean is amazing - biggest fetch on the planet.

I'll bring a set, and I think Sal will, so at least we'll have two going. I'll find a local chart that we'll use for the exercise.

Perhaps, but not for this exercise - it's in preparing a chart ahead of time with lines of magnetic declination. I suppose people could try it with folded paper and compare results.

I think if we can get enough so that people can work in groups of 3, no larger, then the exercise can be done. I think more than 3 people, it starts to lose its value. So while I'm at it - we could try a navigation exercise in groups to get into the habit of group planning. What do people think? John

Hi, All - I'm trying to gauge an activity I'm thinking of doing for the navigation workshop. There is an exercise I can walk people through by actually going through it, *or* you can see it done on slides. I think it's better to do it in person, but it requires some equipment - this equipment is actually quite useful. I use it all the time in trip planning, so I actually recommend having it, but I don't want to force people to buy equipment. Here's the list: Weems and Plath marine navigational parallels - about $15 Weems and Plath marine navigational dividers - about $20 Hand-held backpacker-type compass with clear baseplate - $20 roughly Printed nautical chart - $25 print on demand Please let me know - email huth (at) physics (dot) harvard (dot) edu or respond here. If enough people who want to attend are willing to get this, I'll suggest a common chart to use - something in the area, so it will be useful. Either way, I'll show you how to prepare charts for "on-the-go" navigation - but I think the hands on exercise is more useful. John H.

I like the compasses with mirrors - just have to wash them off - I splash some of my drinking water on them at the end of a paddle My standard is the Suunto MC-2 I find that my sighting precision increases, and I can also look simultaneously at the dial and visually correct for variation - just makes my life easier. Just my preference.

That was Dana Dourdeville, student at Brown, was a track athlete at Old Rochester HS. NOAA has an archive climate data center - you need to specify the dates you want conditions for and the station location and they'll e-mail you the information. Water temp was 38 degrees F, I recall that much about it - New Year's Eve. The search was suspended when the storm started to hit. I have a query in for the weather conditions, will post when I find.

Yup, Leon has it correct. The assumption is that the course made good is perpendicular to the current direction. As you approach the speed of the current the angle heads more and more directly into the current until you're heading directly into the current and there's no solution. This revelation hit me quite practically at Woods Hole. At certain times, the current hits 3 knots and there is a huge amount of boat traffic. I was with an instructor who wanted us to do a ferry angle across when the current was running this strong. The resulting angle was so big, that I figured I'd be in the channel for way too long a time, so I just headed perpendicular to the current and paddled like crazy to cross before another boat came through. I then eddy-hopped up the far side. That was quite the lesson. I was with another paddler at the time, when we both started out with our ferrying and when I saw all the boat traffic and our exposure to it, I said "what the heck, I'm just running straight across, heck with the ferry" and my buddy followed me. I'm not sure whether the instructor took kindly to this, but it seemed prudent given the amount of traffic passing through.

The 'space' of possible paddling speeds, current speeds, and angles makes it tough to come up with any easy-to-remember way of taking care of all cases. However, what I keep in my head is the following: most folks paddle at about 3 kts. Most crossings of any consequence are at 90 degrees to the current. Using this - there's a fairly easy 10-20-30-40-50 rule that goes in increments of 0.5 kts Current speed Correction angle 0.5 kts 10 degrees 1.0 20 degrees 1.5 30 degrees 2.0 42 (40) degrees 2.5 55 (50) degrees The relation is pretty linear up to 2 kts of current, and then you can see the divergence set in. At 3 kts, there is no solution. But, the 10-20-30-40 rule works pretty well. In some busy channels, i'll shoot right across if there's a lot of boat traffic, and let the current carry me, so I'm not in the channel as long. In some cases, if the winds blowing against the current and creating waves, I'll surf the waves, so that gravity is helping me fight the current. There are all kinds of exceptions to keep in mind. OK, on the topic of channel depth - it's a tricky subject, but I'll take a whack at it. There are two figures below. The top one is just a tube that has a change in diameter. If there's a constant pressure difference between the two ends, the speed of flow in the wide diameter is lower, and when there's a constriction, the speed increases - this is how the volume of water passing through is a constant. This is called the 'continuity condition'. So, imagine a V-shaped channel like the second figure. Take two snap-shots of the tide cycle - if the depth of the channel is about the same scale as the height of the tide, then this is relevant. When the tide is low, the area of the channel available for water to pass is constricted, so you'll get a higher speed of flow, when it's at a higher part of the tide, there's more cross-sectional area available for the flow and the speed drops. It depends, of course, on the shape of the channel and the height of the tide, but you get the idea. I've seen exactly this happen at the cut on South Beach near the Monomoy's. At low tide, the current is appreciable, because the cut is pretty shallow, but at high tide, the current drops off appreciably.

Hi, Warren - I'll talk about one approach I use - it's a way of preparing charts somewhat like what I have in my posting. There are a couple of issues that can be confusing and can waste time on the water. Typically when the chart is folded up to the section you want to see, the scale is often hidden - so I draw magnetic lines spaced by 1 nm throughout the chart. This helps in two ways - one is that you have a handy scale to use - use the little lanyard in the hand-held compass to look at a course, and then stretch it perpendicular to the lines in the chart to estimate distances. The lines drawn with magnetic declination in means that you can steer magnetic and not have to hassle with a lot of addition and subtraction, trying to remember rules like "east is least". Now, this is not always advised by instructors. I was on a course led by Shawna Franklin who was a "east is least" fan, and she also took exception to my drawing magnetic declination lines on the chart saying "I don't have the time to show up in a new town, purchase a chart and draw in magnetic lines like that." Well, I'd actually done just that the night before. I've found that a simple, visual approach reduces the chances of error and provides a kind of intuitive feedback. The link below is an article about a guy who was crossing Nova Scotia and used a declination of 18 deg. east rather than west and got lost in the process: https://static.squarespace.com/static/503d2a37e4b0344ab347611e/t/50491384e4b0960a81cd4c82/1346966404307/ Anyway, I'll go over this in the course. Best, John H.

Warren - OK, I tried to do this as a paper exercise. The first thing that came up was that I saw the crossing as 1.3 nm, not 3. I'm attaching a jpeg of the chart I used, including the scale at the bottom. The solid line is my assumed course. Normally, I'd probably make a deliberate compass error to hit the other side of the strait to the north of the path indicated, just in case fog rolled in, so I don't blunder into the reaches of Jack Bay and wonder what happened. But in this case, I just eye-balled the most direct route. I'm attaching my spreadsheet for current calculations. Comments - although the speed doesn't change a lot, even 0.5 its causes some change in heading - something like 9 degrees - not a huge amount, but something to be aware of. I got a magnetic heading of 98 degrees. On the jpeg, I drew in magnetic lines spaced by 1 nm. I got a crossing time of 25 min at a speed of 3.1 kts, so arrival at 8:55. Biggest issue is the difference between my estimate of distance and yours. I used chart 16707, not 16708. John H. Ferry angle.xlsx

Not to be a party pooper with the secrecy - Cohasset, Little Harbor on the South Shore both have nice standing waves develop. Going up north, there's this connecting river between the Sheepscott and the Kenebec called the Sasanoa (I think) there's an "Upper Hell Gate" and "Lower Hell Gate", which have nice standing waves, depending on what part of the tide cycle you're on. "Hell Gate" is Dutch for what is basically a reversing rapids in a tidal estuary. I'm sure there are plenty of others.

If you folks do find some recommended outfitters, would it be possible to post the information here as well? If not, can some of us sign up to get info? I've been wanting to paddle in the Northwest Fiords for some time now.

Good read, for sure. Thanks. This guy, Dana Dourdeville - well, it's sad: http://www.boston.com/news/local/massachusetts/2014/01/02/kayak-missing-brown-student-found-mass/XXOZIDKJzPEyv0OQ9V9V7O/story.html Water temps were 38 degrees, and then that storm

A lot of marine shops carry flares - for example there's a place about a quarter of a mile from my place on the Cape that carries Pains Wessex flares. For the reasons Peter mentioned, I carry them. It's advisable to rotate them out of circulation on a regular basis, as they do degrade over time. It seems like a waste, but you don't want to be in a position where they fail you when you most need it. As far as people seeing them - since flares from guns have a distinct coloration and the way they're shot is distinctive, I suspect/hope that anyone who is in a position to spot them wouldn't mistake them for something else. It's good to keep in mind the likely viewing range for a flare. E.g. call for help on the VHF, and when you think they're within spotting range, then set off the flare. If people are on the lookout for one, it'll help them locate you quickly, but if they aren't on the lookout they might not think too much about it. My "kit" is VHF, flare gun, and strobe if I think I'll need it. If I'm going to be out at a remote location, I also pack a parachute flare, smoke and also water dye, although I've never used these. These are more of nervous "what-ifs". Parachute flares go higher and stay up longer than normal flare guns - so the spotting distance is larger.

In case you're curious about what a flare gun can do:

I had one suggestion on tides and tidal currents. As many of you know this can be a tricky business, but I'll try to tackle this.

What would people like to see in this workshop? E-mail me at huth (at) physics (dot) harvard (dot) edu