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Thread: Sooty Tern Capsize, but Not Serious

  1. #1
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    Default Sooty Tern Capsize, but Not Serious

    Here is another capsize story, this one not so serious.

    Since launching our Sooty Tern, Trondra, we have had her out on the Otago Harbour here and on a small lake not far away, several times, and then away for three weeks on Lakes Wanaka and Benmore. At Wanaka we were staying in the town and doing day-sails. Benmore was our first cruise, with our club, the Otago Trailer Yacht Squadron, over Easter. Lake Benmore is a hydro-lake about three hours' drive north and west of Dunedin.

    On Lake Wanaka, in front of the town, I did a capsize drill, in calm conditions, after the examples of Max, Bruce, and others. (Thanks for the videos.) I had 48kg sand ballast in her, but no other gear. She floated on her side, half out of the water. I released the halyard and was able to right her quite easily by standing on the centreboard. The yard came down as the mast came up, and she did not roll over the other way. I bailed her out sufficiently and rowed ashore. Alison took photos but I was a bit far away.

    My second capsize was a week later, accidentally, on our second day on Lake Benmore. Both of us were on board with all our camping gear, but I had purposely left the sand ballast behind. We sailed north up the lake with a nice following breeze, for about an hour, then passed through a narrow channel between the mainland and an island, instead of going around the island. Most boats do the same. The northern (lee) side of the island was flat calm. Then the wind came around from the north-east, and other yachts near us started beating into it. We started doing that too, but a stronger gust hit us and pushed the boat rail-under. I released the main sheet, of course, but Alison was on the lower side and could not move across quickly because of the oars along the centre of the boat, and I could not lean any further out.

    Once started, the boat went over onto its side very quickly and smoothly. Neither of us got our heads wet and we still had our hats on. From the water, I released the main halyard and worked my way around the mizzen to the other side where I climbed up onto the centreboard and pulled her upright easily enough, but this time the main yard only came down halfway because the halyard got a kink in it, which caught in the hole in the cleat. I slid in and was going to help Alison out of the water but by this time two power boats and two of the yachts of our party had arrived, so Alison got onto one of the yachts as we were all going to the same place for the night. They immediately lent her some dry clothes to change into. One of the power boaters had a wash-down pump which he used to pump water out of our boat while his son bailed with my big bucket and I used our built-in hand bilge pump, which was not really intended for that amount of water. When the water was bailed out sufficiently, I tried the motor but it had been under water and did not start, so I was invited onto the yacht and given dry clothes, and Trondra was towed to where we were to camp for the night. Another friend let us sleep on his yacht, instead of pitching our tent, while he slept on the one that had towed us.

    Everything was tied in, so nothing was lost. Our clothes and sleeping bags were in dry-bags in the end compartments. Nothing got wet that mattered. With help and advice from our friends I dried out the motor's spark plug, drained the carburettor, and removed water from the petrol. When all this was done we put the motor back in the well and it started immediately.

    We were both glad I had done the drill on Lake Wanaka, so we knew how to right the boat and bail her out. Now I had also learned how to deal with a wet motor. The water temperature was relatively mild at 15 degrees C (59F). We were suitably dressed and did not get cold, in the time we were in our wet clothes. If we had just been on our own, we would probably have been able to bail her out and row or sail to the nearest beach, but it could have been more serious. We were thankful for the help at hand. I will take the ballast another time. Making lead pigs might be on the agenda. Perhaps the boat is more suitable for just one person on a camping trip, which is what I really built it for anyway, but we wanted to try it with two, in company. The weather was mild and sunny. Since we have come home, winter has arrived.

    Cheers,
    Ian

  2. #2
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    Default Re: Sooty Tern Capsize, but Not Serious

    Yep, that Sooty Tern is a real deathtrap, all right. Glad you're okay though, Ian!

  3. #3
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    Default Re: Sooty Tern Capsize, but Not Serious

    Thanks, James. Glad you're OK, too. Sad about those kayakers off Sequim. I hope the third one recovered OK.
    Ian

  4. #4
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    Default Re: Sooty Tern Capsize, but Not Serious



    A boat that has a high sail area to displacement ratio is susceptible to down flooding if it has low form stability, is compromised further by a low freeboard, compromised further by no side decking, compromised further by inadaquate side buoyancy and compromised further by a rig and sail planform with a higher center of effort, when sailing in gusting blustery conditions. Without changing those factors, in these conditions open boat forms tend away from sail and oar comproimise to higher freeboard, displacement and form stability.



    One person standing on a centreboard of about a fixed length has a given righting moment that can right so much boat/ submerse so much buoyancy. Compared to a smaller boat this compromises the ability of a larger boat to be self rescued to sailing away under control as quickly.

    Ian to optimise your current arrangement, go back out and repeat the buoyancy test. This time take various size fenders/ rollers and lash it under the thwart seat intersection. Find out what the volume is of the biggest fender that when strapped under side benches still enables you to sufficiently easily:-

    A. Reach up and climb onto the centreboard at 90
    B. When standing on the centreboard still right the boat from 180.

    Beyond a certain volume you won't be able to reach up enough and get onto the centreboard (although this is a bit easier in narrower beam boats) or submerge the buoynacy suffciently easily: just below this is your optimum side tank volume. Go back and build it in plywood into your boat. If you can't, build a box/ buoyancy pod and secure it under the seats. If you do this you will:-

    A. Have less water in total in the boat after you right it.
    B. Have some water in the boat to temporarily increase its displacement and form stability while you sort it out. With a big boat pushing 20ft you will have to accept there will be more than ideal amounts of water in the boat after recovery compared to a 12ft boat like Scamp for example. One benefit comes from that low freeboard is easier re boarding up out of the water without any assistance.

    Fore/ Aft and side bulkheads hold this central but this conflicts with sleeping in it according to James. A step forward optimisation would be to arrange two side tanks holding two assymetric canted foils in each tank side face for the predicted heal angle leaving the central area centreboard free to sleep on with two plywood frames at the case ends to reinforce the structure.

    In these shallow boats, lead doesn't get the weight much lower than sand or water unless its at the foil tips. Neither is it adjustable on the fly per the conditions. On a re design incorporating twin offset assymetric foilks, a flat sealed cockpit floor might allow for a sub floor water ballast tank of equivalent weight that is emptyable under oar to reduce displacement and resistance and a removable thwart for front to back walking. Ballast to the designed displacement waterline will mainly improve the upright waterline beam form stablity and inertia but it's action as keel stability occurs later than rail crew weight which is gives both form stability through displacement and earlier and greater sail carrying power.

    Thus the AT/NY/ST has a great many virtues but they are not optimised for windy blustery conditions short handed without the weight of 3 people on the rail with an eye to weather to reduce healing when the speed related wave trough isn't there to leeward.

    Ed
    Last edited by keyhavenpotterer; 04-20-2015 at 09:00 AM.

  5. #5
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    Default Re: Sooty Tern Capsize, but Not Serious

    The group of Sail & Oar™ folks from Humboldt that I do a lot of events with tend to carry oars either on top of the gunwale or outside it -- what the Aussies call "torpedo style" I believe. It makes sitting on the rail impossible, but does keep the interior of the boat free. Up there when someone swamps their sailboat, we usually swim it to shore and bail it out there -- or dump it out if really full. Simply amazing how little water a folding bucket or bailer will move when the boat is full of the stuff...

    Glad you didn't lose any gear and learned all about recovery.
    "The enemies of reason have a certain blind look."
    Doctor Jacquin to Lieutenant D'Hubert, in Ridley Scott's first major film _The Duellists_.

  6. #6
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    Default Re: Sooty Tern Capsize, but Not Serious

    Redesigning the boat makes no sense. This is bringing an unnecessary solution to something that isn't a problem. The first capsize was on purpose. It was a test. All went well. The second capsize was the skipper's error, and I'd venture it was due to several choices made before the boat even left the beach. First, he left his ballast at the dock. Second, his moveable ballast (his crew) was sitting on the lee rail (forward of the thwart perhaps?) when a gust hit and pushed the rail under. It's up to the skipper to keep his moveable ballast in the proper locations while sailing. This is a conversation you have to have with your crew before you leave the beach. If they don't know the right place to be you'll have to put them there.

    I'd also avoid "torpeedo style" storage of your oars for general sail & oar work. Find a safe, more or less out of the way place to lightly lash them down. But don't take away your railspace. That's where your moveable ballast goes when things get peppy out there.
    Quote Originally Posted by James McMullen View Post
    Yeadon is right, of course.

  7. #7
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    Default Re: Sooty Tern Capsize, but Not Serious

    I've done a fair bit of sailing on Benmore, the water is cold enough to be a hazard to health but the worst thing is that wind direction and strength can be very changeable. It can be a very challenging place to sail, even in what appears to be very nice, stable weather. No warning, just big gusts from completely different directions to the prevailing winds so boats sailing in that area need to be such that they can cope with rail under situations.
    There are a couple of trailer sailers at the bottom not far up from the dam, and quite a few others have needed help.

    This is a mountainous area, cold air pools up in the valleys and when heavy enough can come roaring down and across the water at speed, I've seen 50 knots out of nowhere on a flat calm warm day when my wife was sunbathing on the cabin top.
    Be vigilant, continually watch the water all around for signs of gusts.

    The advice from Ed and Yeadon is as good as you'll get, I'd add to that a suggestion that you might get four 600 mm inflatable fenders, and strap them inside the gunwales forward and aft of your crew positions. You dont want so much bouyancy there that it makes the boat impossible to roll back from an inverted position, but enough to support the crew rolling in over the side once righted and before bailed out.

    Those fenders make very useful rollers should you want to haul the boat up the beach.

    John Welsford
    An expert is but a beginner with experience.

  8. #8
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    Default Re: Sooty Tern Capsize, but Not Serious

    Thanks for all your helpful comments and advice.

    I acknowledge that my decision to leave the ballast behind was not the right one. I thought that the weight of us and our gear would compensate, and perhaps it was something to do with knowing that we would be with other boats the whole time. My conclusions are to swap my sand bags for long tubes of gravel and lash them in securely at all times along the inner floor boards against the sides of the c/case, and lash the fenders under the side benches. There are six spaces so I'll get two more fenders. And yes, the fenders will make good rollers.

    I made the oars to fit into the length of the cockpit area along the bilges, to keep the weight low, but they wouldn't go there with the big buckets we had some of our gear in, so I'll do something about that too. I'm not concerned about sleeping in the boat. The Shetland-style oars are a bit clunky at 3kg each, but they work well. They are probably heavier than they need to be.

    And vigilance, remembering that we are not quite as agile as we once were....... I'm not sure when the next outing will be, though.

    I can say that I did quite a few camping trips on Lakes Te Anau and Manapouri here in the 1990s, by myself in my sail and oar Swampscott (Dion) dory Clarsach, without capsizing, except on purpose. I like your boat too, Thorne.

    Alison did a fine job on our Eun na Mara Islesburgh (the red one). She was very good at backing the jib. Our longest trip was for six weeks.

    Good to meet you at PT 2013, James, Tim and John, and Bruce of Row Bird too. We'll be there this year too.

    I have other threads at "Greetings " on People and Places, and "Southern Sooty Tern" at Building/Repair.

    Cheers,
    Ian
    Last edited by IanMilne; 04-21-2015 at 08:59 PM.

  9. #9
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    Default Re: Sooty Tern Capsize, but Not Serious

    Hmmm, you know, I'd never really thought about the outboard getting flooded in a capsize. My Honda instructions say to do just what you did, but that seems like something better done on shore. I wonder if there is a good and easy way to seal the carburetor and exhaust so that it doesn't take on water but is easy to remove the seals and use. Any ideas?

  10. #10
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    Default Re: Sooty Tern Capsize, but Not Serious

    I don't understand all the fuss and anxiety about small open buoyant boats tipping over occasionally. They do that. Just go watch a sailing race off the beach any weekend. Seems to me that all went exceptionally, and unremarkably (if I may use both words in the same sentence) well. The help that was there was kindly offered and gratefully accepted, but was not really required. If the moveable ballast had moved faster, the capsize may not have happened, but I'd stay away from that. Kind of like "Does my bum look big in this?" Was the capsize your wife's fault? NO WAY! It's just part of sailing a small open boat in blustery conditions. Get back out there ASAP and enjoy before winter sets in!

  11. #11
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    Default Re: Sooty Tern Capsize, but Not Serious

    Hi Scott. I will try to remember to close the tank vent and the fuel line when I stop the motor and start sailing. I think that's all I can do. I will have to do that anyway if I take the motor out of the well and put it in the stern locker, and put the box in the well to fair the hull.
    Ian
    “Old Joke: ‘A bench fitter works to the nearest thousandth of an inch. A loco fitter (steam) works to the nearest inch. A shipwright works to the nearest ship’.”
    Alan Byde, Canoe Design and Construction, Pelham Books, 1978

    “...old maxim, 'A fair line supersedes any given measurement'.”
    Allan H. Vaitses, Lofting, International Marine, 1980

  12. #12
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    Default Re: Sooty Tern Capsize, but Not Serious

    Hello Phil,

    Thanks for that. I didn't mean to create a lot of fuss and anxiety, or to imply that our capsize was my wife's fault, which it absolutely was not! There was no great drama. We were happy to be helped and the others were happy to help. It was a good learning experience, in a sheltered situation. I was never a dinghy racer but I know capsizes are routine for them. I did the drill to show myself that the ST could be righted the same way, and it worked. It's all good here.

    Cheers, Ian
    Last edited by IanMilne; 07-09-2017 at 07:00 PM.
    “Old Joke: ‘A bench fitter works to the nearest thousandth of an inch. A loco fitter (steam) works to the nearest inch. A shipwright works to the nearest ship’.”
    Alan Byde, Canoe Design and Construction, Pelham Books, 1978

    “...old maxim, 'A fair line supersedes any given measurement'.”
    Allan H. Vaitses, Lofting, International Marine, 1980

  13. #13
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    Default Re: Sooty Tern Capsize, but Not Serious

    Just to complete the story, Sooty Tern Trondra now has 60kg of lead ballast permanently bolted into the bilges. See page 2 of my thread, "Southern Sooty Tern". The effect is good.
    Ian
    “Old Joke: ‘A bench fitter works to the nearest thousandth of an inch. A loco fitter (steam) works to the nearest inch. A shipwright works to the nearest ship’.”
    Alan Byde, Canoe Design and Construction, Pelham Books, 1978

    “...old maxim, 'A fair line supersedes any given measurement'.”
    Allan H. Vaitses, Lofting, International Marine, 1980

  14. #14
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    Default Re: Sooty Tern Capsize, but Not Serious

    I bet that helped a lot. I have about 40kg of lead ballast in the Hvalsoe 18. She'd be pretty lively under sail without it.
    Quote Originally Posted by James McMullen View Post
    Yeadon is right, of course.

  15. #15
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    Default Re: Sooty Tern Capsize, but Not Serious

    I do like to have my oars lashed in to the bowsprit position. I have a couple of webbing straps set up for this. I do the same with the masts when they are down and in the boat, one forward one aft. Just borrowed that from the Norse faering sailors who have been pushing these oar and sail boats around for a bit. That way you can have the oar length that you need and they are out of the way sailing.
    Ben Fuller
    Ran Tan, Liten Kuhling, Vernon Langille, Josef W., Merry Mouth, Imp, Macavity and a quiver of unamed 'yaks.
    "Bound fast is boatless man."

  16. #16
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    Default Re: Sooty Tern Capsize, but Not Serious



    This photo of a I think ,a Caledonian Yawl provides another possible solution, one I'm interested in pursuing, especially for extended along shore passages. Lot's of buoyancy, protected sleeping and storage.

    What do people think?
    '' You ain't gonna learn what you don't want to know. ''
    Grateful Dead

  17. #17
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    Default Re: Sooty Tern Capsize, but Not Serious

    Thanks, Tim. Good to hear from you. See you in September!
    Thanks for those suggestions, Ben and Peter. When anybody else is in the boat with me now, I carry the oars in the bottom of the boat, where they are completely out of the way, and do not restrict the movement of the "forward hand". The open area of the boat is 10ft long, so I made the oars 9'8".
    Regards,
    Ian
    “Old Joke: ‘A bench fitter works to the nearest thousandth of an inch. A loco fitter (steam) works to the nearest inch. A shipwright works to the nearest ship’.”
    Alan Byde, Canoe Design and Construction, Pelham Books, 1978

    “...old maxim, 'A fair line supersedes any given measurement'.”
    Allan H. Vaitses, Lofting, International Marine, 1980

  18. #18
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    Default Re: Sooty Tern Capsize, but Not Serious

    I tried for 9'6" oars on Ran Tan and they were too short. Not sure I would have carried them in the cockpit anyway as Ran Tan is a little lively, has a hiking strap etc, and sometimes needs a quick shift across the cockpit. My trim ballast is a couple of 25 pound bags of shotgun shot in plastic bags that it comes in, then into canvas bags. Useful to carry to windward or to trim the boat fore and aft when rowing. A flexible plastic or canvas water bag is also handy, 5 gal gives 42 lbs. 19 liter= approx 19 kg.
    Ben Fuller
    Ran Tan, Liten Kuhling, Vernon Langille, Josef W., Merry Mouth, Imp, Macavity and a quiver of unamed 'yaks.
    "Bound fast is boatless man."

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