Lbeale Posted October 2, 2005 Share Posted October 2, 2005 Deb D. and I planned this trip with high expectations yet on a cautionary note. A sunny, warm October day brought light S winds of 5knots on the morning with a forcast of maybe S winds of 10 knots for the afternoon. We, Kevin O'Malley, Sam Hollander, Deb Dempsey and myself launched latter than expected but the paddle as planned seemed realistic if we cut our time short on the islands. In preparation for this trip, Deb and I tried to talk to everyone we knew who did this trip just to make sure we could find our way back to the put-in. I called Adam B. and emailed Jed L. to get any quirky navigational tidbits. Words of wisdom were make sure you have your compass bearing and, keep looking back to get land marks when paddling out to the Islands. Okay got it--plus Sam had done this trip in the not too distant past. Things were looking good for my first navigational challenge. Made sure everyone had their own laminated chart for the crossing with inserts of the Islands and Rye Harbor, radios and cellphones just in case, we were ready to go. Paddling with a compass reading of "120 against the high tide. The winds from the South were mild so the paddle out was pleasant. Kept looking back at the landmarks-Deb was the best at this task. Got to Star Island reveled in its beauty and, had a quick but enjoyable lunch on a grassy knoll with fine friends. Okay, nice day so far-nice even as we get into the boats to paddle back at 2:30. Some people told us that the trip was not a big deal if not boring. I guess they are right. Sam was great in making sure we had the tower at our back--not the side of the tower--but the front of the tower--an important consideration. As soon as we start paddling back and out of the wind protection of the islands, the winds and the swells picked up considerably in a short time. Now the swells are 3-4 ft and getting bigger and, the winds were S 15 plus. Still keeping our compass bearing at 300 we could see the water tower and the row of white houses that look like sailboats at full sail in the distance on the mainland shore. Keeping that compass reading at 300 we figured we were directly in line if not close to our put-in-- However, as we got close to the shore line, the put-in was nowhere in sight even though we kept to our compass reading religiously. Also, our landmarks for the put-in looked different as the sun started to set and the tide was low. Now what? Luckily, we were not that far off from the put-in and got to it within a mile or two. But of course, Kevin, Deb, and I following Sam in through the surf landing, just had to go over and get dunked. Looking like three drowned rats on the shore, we laughed at each yells of "going over". So, what were the lessons learned?? This might be more obvious to the more experienced paddlers with navigation skills but, for someone who is trying to apply what I learned from my NSPN navigation teachers: 1) Compass reading might be correct but winds affect drift of boat. I know, I heard this a hundred times in leadership training but now I get what it means. Now I just got to figure out by how much winds affect drift. Any suggestions for factoring the wind in getting an accurate reading on the compass????? I seem to remember a formula for this calculation, but I forget what it is. 2) Don't wear sunglasses when taking landmarks--take them off and then note the landmarks--on the way back the sun is different and the shoreline looks different--what looked like a green shed on the way out, on the way back the shed is now a small white house with windows. 3) When people tell you to "keep the tower to your back" that means keep the face of the tower to your back--not just "the tower" -- thank you Sam for getting us to head back in the right direction-- 4) Even on beautiful sunny days--listen to the weather forecast as much as possible--within in less than two hours, the winds changed in gust for us--luckily we did not leave any later than 2:30 pm. 5) If you do lose your sightings, it is better to paddle close to and travel along the shore and get your landmark bearings that way. If people are too tired to paddle anymore, land and ask someone for directions. We did not have to land for directions, but much longer on the water we would. Recommends for an Isle of Shoals trip: Small number of paddlers experienced for this level of trip (we were four paddlers), charts for everyone not just a few, did homework before trip and ask more seasoned paddlers for guidance, have someone who did the trip with you (if possible), lots of landmark sightings for both directions, but particularly for the return trip (though landmarks were confusing off shore, as we got closer we could pick up the landmarks). Also, leave early and don't stay late because those winds change and it can be a slog back to the put-in. We did okay with our time but I would of preferred an even earlier launch. The NSPN Club has some great paddlers who are more than willing to share their wisdom with less seasoned paddlers like myself. Deb and I did the homework and then asked people for guidance. This was my first trip practicing my limited navigational skills and, the guidance I recieved was extremely helpful. The worst that happened to us was we were off by slightly more than a mile from the put-in due to unexpected strong southerly winds. So thanks to my fellow companions on yesterday's adventurous yet fun trip and, to those who guided us safely with their navigational expertise. Les Quote Link to comment Share on other sites More sharing options...
Mysticbos Posted October 2, 2005 Share Posted October 2, 2005 Les Excellent trip report of our wonderful experience. The Isle of Shoals in the fall sunlight was absolutely gorgeous ! Not to be missed by anyone. Wonderful day with wonderful company. Thanks Les, Kevin and Sam! Deb Quote Link to comment Share on other sites More sharing options...
JohnHuth Posted October 2, 2005 Share Posted October 2, 2005 Sounds like a fun trip - I'm itching to do this some time. What I recall is that about 3% of the wind velocity shows up as current (called Eckman transport). Then there's the force of the wind itself on the kayak. This has a considerable variation. Also, this force scales like the square of the wind velocity, so, you can't really give a number like "5%" of the wind velocity. Different hull shapes give different leeway under wind conditions. Probably 10% of wind velocity for winds below 20 knots is a good drift to allow for, but there can be a factor of 2 variation in this rule of thumb. I recall having to make about a 25 degree correction for a 20 knot beam wind on a crossing. Quote Link to comment Share on other sites More sharing options...
bob budd Posted October 3, 2005 Share Posted October 3, 2005 >1) Compass reading might be correct but winds affect drift >of boat. I know, I heard this a hundred times in leadership >training but now I get what it means. Now I just got to >figure out by how much winds affect drift. Any suggestions >for factoring the wind in getting an accurate reading on >the compass????? I seem to remember a formula for this >calculation, but I forget what it is. You need a "range" if you can find one. Line up two objects in front of you, one can be on land (tower, etc.). There might be lobster buoys, navigation buoys, bits of rock, etc. If you can manage to keep in line at one point in your journey, you can note the compass bearing that kept you on your intended course. You can hold this compass bearing under the assumption the current/wind continue to exhibit similar influence on your progress only in the absence of more rigorous means. The further apart the two objects are the longer you have maintained course and the better your estimate. This and other methods are approximations and require constant vigilance and adjustment. You can estimate the distance to a faraway object using your the last joint of your thumb which is roughly one inch long. As I recall the inch translated to 10 feet at a mile. For example two thumbs equal a 20-foot tower at one mile, one thumb equals a 20-foot tower at two miles, etc. By tracking your progress to the tower you get another idea if you are preceeding at your expected pace. Implicit in this is the expectation of ones forward speed and thus at least one additional approximation. Also there is the accuracy of the objects height as the seas rise and fall and obscure the horizon, provided you can even see it. Quote Link to comment Share on other sites More sharing options...
JohnHuth Posted October 3, 2005 Share Posted October 3, 2005 The Micronesian Islanders had to make long crossings between islands (100+miles). To estimate drift, they would sail some distance off the island, and then stop and watch what would happen to the vessel relative to the island under ocean conditions to estimate drift. I've experimented with this technique and found it works reasonably well. It does take a bit of patience to sit idly in the kayak for 10-15 minutes to let things move around, when there's a temptation to be active and paddle, but it does work. The story of Micronesian navigation techniques is the subject of a fascinating book called "The Last Navigator". John Quote Link to comment Share on other sites More sharing options...
Lbeale Posted October 3, 2005 Author Share Posted October 3, 2005 Thank you Bob and John for your navigational tips for dead reackoning and winds. Will try to remember your tips next time out offshore. I like the idea of just sitting in you kayak for 10 minutes just to see what the boat wants to do then navigate based on that information. John, if you are thinking of going to the Isle of Shoals now is the time. We were lucky enough to land and get permission to stay and have a picnic on Star Island. I've heard told that during the summer months it's not so easy to get permission to land on this island and explore. Les Quote Link to comment Share on other sites More sharing options...
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