Showing posts with label Some. Show all posts
Showing posts with label Some. Show all posts
Wednesday, 22 June 2016
Discovering some limits Island Head Creek to Great Keppel Island
November 28, 2015
We followed our previous day’s track on the chart plotter downstream in the pre-dawn light to clear the mouth of Island Head Creek before the lowest of the tide. We were surrounded by four other boats including our friends on Seabreeze and Howzat clearly with the same idea in mind. Sticking very close to our track made exiting the creek much less stressful than the entry had been. The theory being, if we didn’t hit the bottom anywhere we went yesterday we shouldn’t hit it there today either. We did see some readings in the two metre levels again inside the mouth but successfully cleared Island Head without bouncing off anything. We love a theory that works.
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| The sun rising as we depart Island Head Creek |
Again the seas just outside were quite rough and confused and we were very happy that our Leisurefurl in boom mainsail is so easy to raise from the safety of the cockpit. The mizzen can also be reached from the back of the cockpit so with those both raised we soon had the genoa unfurled and set course for Great Keppel Island 60 nautical miles to the south.
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| Rick and Howzat disappeared into the distance again in the downwind conditions |
The coastline here is all part of the Australian Defence Force’s Shoalwater Bay Exercise Area and as such is completely uninhabited, unless the Army, Navy or Air Force are there blowing the place up again in which case we cruisers are forced to sail by well offshore. The geology is quite dramatic with many small, rocky islands rising vertically out of the water to quite significant heights. As soon as the sails had been trimmed and the boat was settled on course, Karen had her sketch pad our recreating a number of the more dramatic looking scenes along the way.
The modest wind blowing around ten knots from the Nor Nor East through the morning saw us edge away from the coast to maintain a workable sail angle so progress was comparatively slow. We gybed back and forwards a couple of times but eventually settled on a long run further offshore in attempt to keep the boat speed somewhere near respectable. The breeze was forecast to strengthen later in the day so we were hoping to pick up the pace in the afternoon or we may be arriving at Keppel in the dark.
Well offshore from Cape Manifold we gybed again back towards the coast. The wind was picking up at last but also swinging around for a while before finally settling in the mid to high teens from almost due North. With our destination now almost due South we poled out the genoa on the opposite side to the main and mizzen and began sailing wing on wing directly downwind consistently making better than seven knots.
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| Our Dreamtime charging downwind wing on wing approaching North Keppel Island. |
With our sails well filled and Our Dreamtimecharging along nicely as ever bigger swells rolled under our hull it was far from the perfect time to hear the ratchet on our game rod suddenly start screaming . We had hooked a large fish that was reeling line off at a scary rate while it was impossible to even slow down the boat let alone stop and back it up on the fish the way you would on a game boat.
Rob grabbed the rod and progressively increased the drag until the speed at which the line was disappearing slowed to a trickle. The fish managed another couple of decent runs but each time Rob was able to manage and then finally stop the loss of line. Eventually he was able to start retrieving line but whatever it was, this fish was not going to give up easily and would try to run again. The battle ebbed and flowed for a few minutes before the stern of the boat was picked up by a good sized swell which we surfed down the face of at nine knots or so putting too much strain on the line. Goodbye fish and goodbye favourite lure. Bugger. Fresh fish for dinner at Great Keppel Island would have been nice.
Mid afternoon the wind began to strengthen further and by the time we were approaching North Keppel Island we were seeing regular gusts over 20 knots. These conditions began to test Ben & Gerry. (The nick name for our new B&G Autopilot) The big swells often swung the stern which presented much more of the mizzen and main to the wind overpowering the genoa. This pushed us off our dead downwind course. The Autopilot was then overwhelmed a number of times as it tried to correct finding the weather helm too strong to overcome.
Reducing sail or even dropping the mizzen completely would have balanced the boat up more but that would mean turning around into the wind and seas to reef and or drop. With the shelter of Great Keppel Island in sight just across the waters we decided to leave things as they were but with Rob taking over the helm from Ben & Gerry.
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| David on Seabreeze got this photo of Our Dreamtime wing on wing as we sailed side by side towards Great Keppel Island. |
By the time we approached the passage between Middle and Miall Islands about an hour and a half later he was questioning the wisdom that decision. The wind was now a steady 25 knots and gusting above that quite regularly. The swells were also standing up steeper and higher in the shallower water. This combination made hand steering physically hard work.
As he constantly worked the wheel back and forward countering the best efforts of wind and wave to send us off course, Karen had the camera out snapping photos of our friends David and Nerida having their own fun and games aboard Seabreeze in the spirited conditions. Marc meanwhile was sitting back engrossed in solving the cryptic crossword in that day’s London Times he’d just downloaded when we regained Wifi service after our days in black hole territory since we reached Digby Island. Rob’s comments about it being hard to get good crew seemed to fall on deaf ears all around.
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| Our friends on Seabreeze hull down between swells near North Keppel Island |
Once in the lee of Middle Island, we were able to turn to wind in reasonably flat water and drop all sails with Rob letting out a huge sigh of relief as the helm resumed its normal feather light feel. We were then left with just a short motor around into the well protected bay at Long Beach on the southern side of Great Keppel.
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| Island Head Creek to Great Keppel Island - 62.7 Nautical Miles – 11 Hours 25 Minutes Average Speed 5.5 Knots – Highest Speed 9.6 knots |
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| The run from North Keppel Island through to the passage between Middle and Miall Islands was spirited to say the least. |
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| Nice and calm in the anchorage off Long Beach on the southern side of Great Keppel Island |
This was always intended to be a shakedown cruise to learn our boat and we had definitely discovered some new limits. Our autopilot problems and experience hand steering in the strongish, downwind conditions convinced us that in future we would probably be better off leaving the mizzen sail in the bag when we sailed wing on wing if the wind was likely to get up.
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| Sundowner drinks on Long Beach after our spirited passage. |
Later that afternoon we hit the beach for sundowner drinks with David, Nerida and Rick where we compared tales of the days passage and told other tall stories. That’s what cruising is about isn’t it.
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Sunday, 5 October 2014
Another Tub Boat and Some Corrections
G.R.G. Worcester's monumental The Junks and Sampans of the Yangtze
is full of some many fascinating boats, this blog could devote itself to that book for years and not run out of material. But since we've been on a jag about tub boats, we'll quote old GRG at length on the Wuhu Tub, drawings of which are shown above from the same source:Floods, droughts, famines, civil wars, and other disasters carrying widespread poverty and distress in their train have brought begging to a fine art in certain parts of the Yangtze Valley.
Normally this is by no means a highly skilled profession, but at Wuhu its followers require to have a knowledge of nautical matters quite out of the ordinary. Here swarms of beggars in tubs cluster round ships made fast to the pontoons and occasionally venture to those at anchor some distance out.
This economical and ingenious custom originated as a practice with two old ladies some 30 or more years ago [i.e., around 1937]. Noting that sampanmen were often fortunate in begging from the passengers of ships making a call at the port, and not having the necessary capital to own or even to hire a sampan, they, nothing daunted, took to the water in the one available craft they did possess, a large wash-tub.
Instant success attended the introduction of this novel form of craft, a success dependent largely on human nature, for the idle passengers on deck are only too ready to be amused by the vociferous and heated competition between the rival crews as they scramble for coins or morsels of food, with all the attendant risks of colliding or capsizing.
As soon as one of the Yangtze passenger-steamers has made fast, several of these elliptical tubs, ranging from 3 to 4 feet across the major axis and sometimes as large as 8 by 6 feet, will appear as from nowhere off the outer side of the ship, varying from the "single seater" variety, paddled with the hands over the side, to one holding a complete family progressing in a style with home-made paddles.
The crew in this case usually consists of a woman who, with the inevitable child lashed to her back, acts as navigator and helmsman, and as many children as the craft will accommodate to paddle. There may be a supercargo in the shape of a baby in a cradle. All the children of an age to do so are trained to hold out their hands in whining supplication.
Does this sound a bit racist? Perhaps it is, and if so I sincerely apologize if it gives offense. It is, nonetheless, interesting from the point of view of our interest in indigenous boats -- in this case, a relatively modern creation (or adaptation) of a boat type outside the western tradition.
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Corrections: Doug Brooks, American builder of Japanese boats, helped correct a few errors of fact or interpretation in my two prior posts on Japanese boats and boatbuilding (this one and this one). Rather than itemize corrections here, I have revised the posts themselves, so if anyone plans to rely on information in either of those posts, please take another look. Of particular interest is that Doug has a new book in the works covering all four of his Japanese apprenticeships.
Wednesday, 6 November 2013
Answers to some physics questions
I start most days early. A cup of coffee is made, and with bed head, and in bathrobe I settle down in front of the computer, and read Google news. I'm not yet mentally ready to write, and this is my way of cranking the mental engine until it starts. It's also quiet. The canine rugs with organs we call the greyhound girls are still asleep, and are not demanding attention. I have several custom news sections including one called boating. Mostly reading this is an exercise in futility. Drunken boaters in boat crashes, the obligatory pedantic stories about how to boat safely, USCG rescues, and the occasional misplaced "Swift Boating", but this morning two items caught my eye.
The first story is about the sinking of a Moose M2 37' catamaran with diesel powered jet drives. It appears one of the drives seemed to be vibrating, and an on board theory developed that the jet drive impeller may have ingested some foreign material such as a rope or the ilk. There were several choices that could have been made here. One was to go back to port on a single engine. The second was to continue on with the vibrating drive, or the third, and least likely in my mind was to attempt a repair.
So as the story goes a civilian on board suggested the impeller access cover could be removed (the round red circle in the photo), and the offending material could then be extracted. The problem started with the belatedly discovered fact that the access cover was indeed below the water line. The end result was as a port authority official told the New York Post, "It was like opening a window during a car wash." This was not quite a nautical description, but once you pull the cork on the "Water Genie's" bottle, it will almost always be difficult, if not impossible to put it back in. The boat's crew very quickly realized this.
Just for conversations sake, let's look at the actual dynamics of the event. A 2" hole in your boat that is one foot below sea level will let in about 80 gallons of water a minute, or 4800 gallons in an hour. Your Rule 1500 gallon per hour bilge pump ain't gonna to do the trick here.
In looking at the access cover I would guess it is about 6 inches in diameter. This gives it an area of 28 sq inches, or about 9 times the area of a 2" opening. So instead of the 80 gallons per minute, it is now about 750 gallons per minute. These are pretty scary numbers. No one was physically hurt, but there had to be some terminal ego damage as $500,000 worth of boat and gear disappeared into the briny. Since the boat was carrying enough life rafts to float 600 people in the event of an airplane crash there was plenty of gear on board to get the 10 crew members safely to the 900' away shore. So if there is a moral to the story, don't open anything below the water line, that you can't stick your finger into to stem the flow, and you should think twice about even that small of a hole. Mother nature never cares what you think or want, so check your below water line fittings and hoses often.
Governor Romney's wife Ann was involved in a unfortunate incident on a Challenger 600 jet. An electrical fire started in the cockpit, filling the cabin with smoke. The crew did a successful emergency landing in Denver, and all ended well. A little later Governor Romney made some comments at a fund raiser as follows.
"I appreciate the fact that she is on the ground, safe and sound. And I don't think she knows just how worried some of us were," Romney said. "When you have a fire in an aircraft, there's no place to go, exactly, there's no — and you can't find any oxygen from outside the aircraft to get in the aircraft, because the windows don't open. I don't know why they don't do that. It's a real problem."
Since it's the silly season, Governor Romney, was humorously pilloried in the press. I thought that was a little unfair, and I suspect a lot of people thought the same. He's not an aeronautical engineer, he's a venture capitalist, so basic physics are not his milieu.
Fortunately I have an inkling about why aircraft windows are designed not to open, and even better I have a my friend George Flavell who is an expert on the subject. George flew large commercial aircraft all of his life, and at one point in his career he was a DC-10 production test pilot for McDonnell Douglas.
So George, what really does happen if a window opens on a jet, let's say at 30,000 ft? George pauses for a second and says, "Well the first thing is all of the air inside the aircraft want's to get out, and badly. Anything that isn't tied down well in the cabin wants out also, and if it's your window, most of the stuff wants to go through you on it's way out. If your seat belt isn't on, you might also find yourself outside the aircraft with along with all of your stuff with a surprised look on your face." Okay George, so it's not good to open aircraft windows in flight, but if you do will the airplane fall apart?" No that's not likely to happen, but if the pilots don't get oxygen quickly, the plane will definitely have some technical issues when it hits the ground with the unconscious pilots in the cockpit."
I might add I think there are a couple of other things to note. I think at first things will be really noisy, but after your eardrums blow out from the rapid decompression, there would just be silence. This is a plus because you won't hear all of the screaming passengers, as they flay around trying to breath air that isn't thick enough to use. So this is why aircraft windows don't open. It's very important they stay closed, smoke or no smoke.
With many thanks to Workboat.com for the use of their annotated photo of the jet drive access hatch.
Fortunately I have an inkling about why aircraft windows are designed not to open, and even better I have a my friend George Flavell who is an expert on the subject. George flew large commercial aircraft all of his life, and at one point in his career he was a DC-10 production test pilot for McDonnell Douglas.
So George, what really does happen if a window opens on a jet, let's say at 30,000 ft? George pauses for a second and says, "Well the first thing is all of the air inside the aircraft want's to get out, and badly. Anything that isn't tied down well in the cabin wants out also, and if it's your window, most of the stuff wants to go through you on it's way out. If your seat belt isn't on, you might also find yourself outside the aircraft with along with all of your stuff with a surprised look on your face." Okay George, so it's not good to open aircraft windows in flight, but if you do will the airplane fall apart?" No that's not likely to happen, but if the pilots don't get oxygen quickly, the plane will definitely have some technical issues when it hits the ground with the unconscious pilots in the cockpit."
I might add I think there are a couple of other things to note. I think at first things will be really noisy, but after your eardrums blow out from the rapid decompression, there would just be silence. This is a plus because you won't hear all of the screaming passengers, as they flay around trying to breath air that isn't thick enough to use. So this is why aircraft windows don't open. It's very important they stay closed, smoke or no smoke.
With many thanks to Workboat.com for the use of their annotated photo of the jet drive access hatch.
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