JohnHuth

Yikes!! Not sure what a person can do other than stay out of the water. There's always a lot of shark activity this time of year - I suppose we were due for something like that, but ….yikes!

Congratulations Warren, good going!!

Dealing with magnetic variation

If the hyperlinks don't work for you, you can directly access the blog at the following location: http://artofwayfinding.blogspot.com Note that some of the material is non-navigational in content (although most is)

Next installment: range and back-bearing to find position

Next installment: Lines of position

Gary - I'm not a GPS user, but I do celestial navigation with a sextant and watch. All of us who do that use degrees, then minutes and decimal minutes... So… 41 deg 14.5 min is my typical format. Note that the best one can do with a sextant is 1/10th of an arc-minute, so I don't go beyond one decimal. Can't help you with GPS, however. I could never get the hang of UTM either. Best, John

Bearings to objects. Thanks to Gary for his advice.

Taking simple bearings. Link here.

Thanks for the feedback! Here is installment 2 of the "on-the-go" navigation series. I'm trying to break it out into bite-sized pieces.

I have a recent experience, maybe worth sharing. This is one of those "oh, you dumb …." for me. I assume full culpability for being an idiot, but I did learn something. Thursday evening, crowded house, I'm looking out at the rock groin in front of my porch - slightly awash at high tide. A woman walks by with three boys in tow. The boys want to go out on the rocks, but the woman forbids them. I think to myself "heck, they're kids, let them explore.". I thought to myself "hey, I'll go out on the jetty myself". Did I mention I'd had a couple of glasses of wine at that point? Might have some bearing on the matter. Anyway, I made it out to the end of the rock groin and took a selfie. I felt quite self-satisfied, and walked back. Now, there's one little spot that has some slick junk growing, and in my hubris, I forgot about that spot, stepped in it, and went ass over teakettle onto the rocks. I got up and walked to the beach, but then discovered my iPhone was missing out of my pockets. I wandered back to the rocks, and miraculously, I found it. BUT, when I tried to get it going - nothing. My wife put it in a tupperware container filled with rice, because she heard of the 'rice in a bag trick.' The next morning, with a bad bruise on my thigh and a bunch of scrapes, I got up and investigated the 'rice in a bag trick". You're supposed to put the cell phone in a ziplock bag full of rice (not enriched) and keep it there for at least 36 hours. I did this, but nada, still didn't work. I found out that it's kind of a long stretch, but for future reference, if you dunk you cell phone in salt water, and want to *try* to maximize your chances of a good outcome, do the following: 1.) Don't try to turn it on - don't push any buttons 2.) Wash it out with fresh water 3.) Clean out any garbage with Q-tips and needles if necessary 4.) Dry as thoroughly as possible 5.) Put in a ziplock baggie with a bit of air left, filled with non-enriched rice, and leave it there for at least 36 hours 6.) After 36 hours, pray, take it out and hope for the best. As it was, I had to go get a replacement. The contacts had corroded. Lesson learned, testosterone+wine+rock groin+ cell phone = bad experience.

I'm trying to write up some of the material I showed in the winter navigation workshops. Here's the first in a series. I could use some "beta testers" - i.e. guinea pigs…to see if the instructions are sensible. Here's a link: Drawing Magnetic Variation Lines

Yeah, it's kind of a crap shoot with this storm. FWIW, I can't make it in any case because of family obligations. I have two "dream" harbor trips - one is Nantasket Beach to the Brewster Islands. The other is taking the old route that sailing vessels took coming into Boston - which was between Hull and the light house, then winding its way to the NW. There's a great life-saving museum in Hull which gives you some ideas of the dangers that vessels coming into the Harbor faced. Worth a visit.

So many tradeoffs! I have a standard issue NRS towline that I've modified by putting a different carabiner on it. I still have to get around to doing the whipping/shrink wrapping thing. Every time I look at it, I think "damn…have to get on it". Mine is daisy chained, except when I unhook it and get too lazy to re-daisy chain it. One of the non-practice tows I've done was off of Little Cranberry Island. A couple in a bullseye sailboat were waving frantically at me. I paddled over - it turns out their boom was broken and they were stranded. They asked me for a tow into the Isleford Harbor. I don't know the precise number, but bullseye's have something close to 1000 pounds in the keel, which make them ideal for first time sailors, but they're quite something to tow with a kayak. In any case, the folks were happy for the tow and rewarded me with a gift certificate to the local pottery shop in Islesford. FWIW, I let out the daisy-chain for the tow, as I didn't want to be too close to the bullseye. You never know what you might need one for. Another non-practice tow was similar - I pulled in another couple across the surf line in a Sunfish, also with a broken boom. Again, I let out the daisy chain, as I didn't want to be too close to them in the surf.

Link to synopsis of MITA cleanup and circumnavigation around Isle au Haut can be found here

Yeah, I noticed the wind was picking up. You guys looked sooo serious. Must've been a slog into that wind. The stretch between Eastern and Western Heads was glorious - swells breaking on the shoals and the north wind cleaning up the wave faces. Dang!

Josko - By any chance were you paddling around the Eastern Ear of Isle au Haut on Sunday morning around 11 AM? I was paddling southbound with my friend Dan and we passed about 6 paddlers going northbound. I had to drag it out of them that they were from Boston/Cape Cod. Snotty weather on Friday, huh? I did a cleanup with MITA on Saturday AM, and then paddled out of Old Quarry on Saturday PM, camping on an island, and then swung around the southern end Sunday, camping in Duck Harbor on Sunday and Monday night, hiking around the island on Monday. John H.

Here's a link to an article on shallow wave conditions - for the expert only: http://journals.tdl.org/icce/index.php/icce/article/viewFile/1140/pdf_38 I've become interested in the tradition of wave piloting in the Marshall Islands and am slowly teaching myself a bit about this. The idea is that waves will refract and reflect on encountering shallow waters. The indigenous navigators in the Marshall Islands could read the patterns of interactions of waves with land and find distant islands. I'm only beginning my own practice of wave piloting, but it's interesting - I often find that there are very distinct wave patterns depending on where I'm paddling. A curious feature is that a sloping shore will reflect low frequency waves much more than high frequency waves. Relating one wave piloting experience - I was paddling up the Sheepscott River. At the entrance there were swells from both the SE and South. As I went up the entrance, where it starts to neck down, the SE swell was extinguished by land and the S swell was amplified a bit by estuary becoming narrower. Right now, I'm playing around with modeling wave interactions with land - there are some nice computer packages out there, but it's not clear that they get reflections right.

Attached is a set of screen shots. Top one is the tide information for Mill Point on the Sasanoa River - subordinate tide prediction. The next one down is the current prediction for Lower Hell gate, and then the next one down is the current prediction for Upper Hell Gate. All are for May 13th and should be for the same time period. For Lower Hell Gate, you can see that the max flood current is maybe just a shade later than the midpoint between low and high from the Mill Point station prediction. Ebb pretty much the same. So, if you just remember the mid-point of high-low for Mill Point station, that's probably close enough. You can see that Upper Hell gate has a funkier current pattern with max flood occurring coincident with high tide at that station - very peaky. Ebb on the other hand is of longer duration (also lower speed) but coincident with low tide at the Mill Point station. Lower Hell Gate has higher currents, clearly. On the Kennebec/Hanson interface, I've only been there on the ebb, but there was a fair amount of turbulence in the little embayment to the point to the south side of the bridge on the Kennebec side of the bridge. On the Hanson Bay side, not so much. I attribute the turbulence to the water getting diverted between the Sasanoa and the Kennebec, so having it downstream makes sense. I'd imagine that the turbulent region would shift more to the north on an incoming tide and probably wouldn't be as bad as on the ebb. I have an e-mail out to my buddy who has paddled this a gazillion times, so he probably knows better for other conditions. The turbulence wasn't too-too bad that it couldn't be managed, but it's a bit funky where it pops up - not the easiest to predict.

That plot was empirically derived. I don't know the answer offhand how to optimize the angle to the wind, but I think that being too close hauled is not optimal. For that vessel, I'm guessing that 70 degrees would be the best you could do. Modern yachts can do maybe 35 degrees - mainly because the keel is so deep. There *must* be a polar diagram for a sunfish somewhere, but I couldn't find one with a cursory inspection. Yes, the AC-72 (Oracle America's cup entry) is a beast!! Check it out on some YouTube videos.

Attached is a file showing wind performance of a replica Poynesian Voyaging Canoe/sailboat as a function of degrees into the wind. You can see it goes faster on a reach than running downwind.

Hi, Dave - Welcome - there are a good group of folks here - always ready to help. Nothing wrong with river paddling at all. If you feel up to getting onto the ocean, there are plenty of people here who can suggest good spots. You can always start out in relatively sheltered areas and work your way up. Best, John Huth

Great, thanks, Cathy, Scott, I've ordered the large scale chart of French Polynesia, now need to see if I can get some more detailed charts of individual islands.

I'm actually contemplating two trips - one sailing out of Bora Bora and because of my ...cough cough...."navigational background" I'm getting a free cruise from Tahiti to the Marquesas to Puka-puka to Mangareva to Pitcairn to Easter Island as an "expert". Go figure, but I'm not turning it down. Speaking of that, did any of you see Ken Finks talk at the MITA 25th anniversary. He set out to do a kind of kayak catamaran trip from the Marquesas through the Tuamotu's to Tahiti. The rig looked awfully rickety to my eyes, and sure enough, two days of swell from the Southern Ocean was enough to start breaking it apart. One of the guys on the trip with him got a real nasty salt water infection and they had to throw in the towel on the whole expedition.

Hi, All - I wonder if anyone knows how to go about getting nautical charts of non-US areas. I'm contemplating both paddles and sailing in some areas. Specifically I'm interested in Jamaica (paddles) and French Polynesia - sailing. Does anyone know of good sources? A cursory online search wasn't terribly helpful, except for the electronic variety - looking for paper-in-hand charts. John H.