I did the calcs on my boat if the mast were made airtight. It adds significantly to the AVS, but of course only helps once a lot of the mast is immersed which is like > 140 deg. So the result is likely not preventing an inversion, but limiting the time spent there.
Desirable and Undesirable Characteristics of Offshore Yachts
- Thread starter Jud - s/v Sputnik
- Start date
That's never been a requirement unless you weren't fully cleared in for some reason. It would have been good to know at the time as the department should have been taken to account over that.
ProaSailor
dreaming my life away...
With added RM at the top from a NACA foil windvane float, the Gougeon-32:
P.S. from G-Wiz! Russell Brown’s New Toy, April 25, 2018
https://www.epoxyworks.com/index.php/g-32-catamaran-g-wiz/
P.P.S. Great place to mount a camera or two!
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olaf hart
Super Anarchist
Yep, the thing to remember about Tasmanian public servants is that they have all reached their level of incompetence and there is nowhere left to go…
Panope
Super Anarchist
Panope's mast is water tight except for 3 bolts (in tight holes) near the partners.
Submerged, the mast would have about 210 lbs. buoyancy.
Flooded with water, it would have a submerged weight of about 110 lbs.
I have no AVS calcs, but I can sure see how a difference of 320 lbs., 18 feet above deck (mid point of mast) could sure make significant difference.
Her tall wheel house, on the other hand, has the potential of providing an even larger righting force...........as long as the water can be kept out.
Nice looking boat, and great little voyager. Looks like you could strap an outboard on that transom too. :lol:So I just put down a deposit on a boat with free standing, water tight spars.
Not sure it puts me in the club though.
https://www.ghboats.com/our-boats/17-salish-voyager/
h34r: IMO mast flotation is of dubious advantage except for quite small boats with low stability and in wind gust knockdown rather than wave knockdown.
Usually in a wave induced capsize you can count on the rig being lost, and always in anything performance oriented.
Keel stepped masts often retain the lower section and break at the first spreaders. Deck stepped, unless in a husky well supported tabernacle then the lot usually goes.
Inversion is about dynamics not statics. These are dynamic events that happen quite quickly.
Usually in a wave induced capsize you can count on the rig being lost, and always in anything performance oriented.
Keel stepped masts often retain the lower section and break at the first spreaders. Deck stepped, unless in a husky well supported tabernacle then the lot usually goes.
Inversion is about dynamics not statics. These are dynamic events that happen quite quickly.
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I think you can count on a Marconi rig being lost in a capsize, they are a brittle structure and experience seems to confirm this. Much less experience with free standing rigs, but at least some examples of them not being lost, and the structure is not as brittle. A free standing rig is the ultimate in a keel stepped rig after all. But I'd agree that in a wave induced capsize static stability or AVS may have little influence. The difference may be in how long you stay inverted.
Interesting that in breaking wave studies (from memory. Nomato expanding on Claughtons work) :
That when a boat model without the rig was knocked down to 120-130 degrees and recovered, another model with exactly the same roll gyradius and the rig fitted, they reported the total roll angle reduced significantly.
Not to be confused with total roll inertia. He found that case entirely due to the roll damping effect of the rig when it hit the water dissipating the remaining roll energy.
At that point the loads on the rig are not excessive ( rolls slowing down anyway ) and even with sails set most rigs do remain intact after this sort of knockdown unless stay attachments fail.
Upside down: In inverted stability it's also shown that if the vessel inverts and has a lower LPS and if the rig remained intact then it can prevent re-righting completely not because of it’s flooding the mast but because it damps and changes the phase of the inverted roll response so much that the inverted LPS is never exceeded unless the waves get much larger than the wave that inverted the vessel.
I don't know about free standing rigs. The combined shear and bending at deck may well be survivable depending on the margin allowed by the designer for composite lifespan.
That when a boat model without the rig was knocked down to 120-130 degrees and recovered, another model with exactly the same roll gyradius and the rig fitted, they reported the total roll angle reduced significantly.
Not to be confused with total roll inertia. He found that case entirely due to the roll damping effect of the rig when it hit the water dissipating the remaining roll energy.
At that point the loads on the rig are not excessive ( rolls slowing down anyway ) and even with sails set most rigs do remain intact after this sort of knockdown unless stay attachments fail.
Upside down: In inverted stability it's also shown that if the vessel inverts and has a lower LPS and if the rig remained intact then it can prevent re-righting completely not because of it’s flooding the mast but because it damps and changes the phase of the inverted roll response so much that the inverted LPS is never exceeded unless the waves get much larger than the wave that inverted the vessel.
I don't know about free standing rigs. The combined shear and bending at deck may well be survivable depending on the margin allowed by the designer for composite lifespan.
Fah Kiew Tu
Curmudgeon, First Rank
They reach it at APS 3-4 for the most part. This place could have been used as a textbook example of the Peter Principle in real life...
FKT
Jud - s/v Sputnik
Super Anarchist
- Thread starter
- #912
BTW (and somewhat randomly, but not really b/c I just happened to be reading about Chile), did you pass through the canales W-E (i.e., coming down the Chilean coast), or from the Atlantic? And what time of year was it? Apparently winter is said to be calmer?
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estarzinger
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we were in chile 3 times, came at it both ways (from the atlantic and the pacific).
To get to chile, down the atlantic is (arguably) a bit easier than the pacific. But once there are the first port it is a whole lot easier if you did the pacific, because southbound (downwind) in the chanels is way way easier than northbound (upwind).
We also did both winter and summer. In the winter the days are pretty short, and the water will freeze around your anchored boat at night. The weather is much more variable in the winter - you do get calm high pressures (very cold) and you get worse storms and you can get winds from different directions (like easterlies) which make picking safe anchorages more tricky. Coming south bound I would say summer is the very clear choice. Going North bound I could understand an argument for winter but I would disagree with it. You can sail/explore year around a bit like the pnw.
estarzinger
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a bit more regarding the atlantic and pacific approaches . . .
From the Atlantic there is basically one way to do it. You get to Uruguay and then go down the coast and turn right at the beagle. We sailed non-stop from iceland down to uruguay, but probably the easiest is a passage from the canaries/cape verde you can also do it from the Caribbean, but it is a lonish way around brazil with some contrary winds and current. It is easier (if you are a competent passage maker) to just get some ocean easting and then act like you are coming from the canaries.
Once in Uruguay, you make your way down the coast in small 2/3/4 night jumps. It starts off pretty easy - weather pretty decent with mostly favorable winds and reasonable harbours. But south of Mar del Plate (agrintine holiday town) - the winds start to get strong - 30 to 40 kts (with clear sunny sky's) blowing off the argentine Pampas is not unusual. You can often sail quite close to the beach so there is little fetch and just power reach in the big winds. Further south you can start to get lows spinning in from the west and the harbours are more tenuous (shifting sand bars and little protection from the wind). One of my lasting memories is getting into Puerto San Julian - the mouth has shifting pretty much uncharted sandbars and you often have to go in straight into +30kts with a (reversing 4kt current). I had read about it because Skip Novak had tried to get in a couple times and never made it. We got the timing right and made it in, just in time to get anchor down for a 50kt breeze. The officials said we were the first sail boat in their memory (like in 20 years). Both Cook and Magellan put down mutinies in there and there is a point called hang-mans point where they were hanged. From there, you keep plugging away south. There is a treat just before you turn right into the beagle if you are willing to bend the rules just a little - On Isla de los Estados there is one of the most marvelous harbors in the world the inner harbour of Port Hoppner - the entrance looks impassable on first glance, but once you get in it is like being anchored in an alpine lake - perfect protection and good hiking all around. We spent a christmas in there with some swedish friends. The you have a final trick bit - Estrecho de le Maire - strait with strong currents and big badly shaped waves, and you can turn right into the beagle and you can mostly day hop between decent anchorages
From the Atlantic there is basically one way to do it. You get to Uruguay and then go down the coast and turn right at the beagle. We sailed non-stop from iceland down to uruguay, but probably the easiest is a passage from the canaries/cape verde you can also do it from the Caribbean, but it is a lonish way around brazil with some contrary winds and current. It is easier (if you are a competent passage maker) to just get some ocean easting and then act like you are coming from the canaries.
Once in Uruguay, you make your way down the coast in small 2/3/4 night jumps. It starts off pretty easy - weather pretty decent with mostly favorable winds and reasonable harbours. But south of Mar del Plate (agrintine holiday town) - the winds start to get strong - 30 to 40 kts (with clear sunny sky's) blowing off the argentine Pampas is not unusual. You can often sail quite close to the beach so there is little fetch and just power reach in the big winds. Further south you can start to get lows spinning in from the west and the harbours are more tenuous (shifting sand bars and little protection from the wind). One of my lasting memories is getting into Puerto San Julian - the mouth has shifting pretty much uncharted sandbars and you often have to go in straight into +30kts with a (reversing 4kt current). I had read about it because Skip Novak had tried to get in a couple times and never made it. We got the timing right and made it in, just in time to get anchor down for a 50kt breeze. The officials said we were the first sail boat in their memory (like in 20 years). Both Cook and Magellan put down mutinies in there and there is a point called hang-mans point where they were hanged. From there, you keep plugging away south. There is a treat just before you turn right into the beagle if you are willing to bend the rules just a little - On Isla de los Estados there is one of the most marvelous harbors in the world the inner harbour of Port Hoppner - the entrance looks impassable on first glance, but once you get in it is like being anchored in an alpine lake - perfect protection and good hiking all around. We spent a christmas in there with some swedish friends. The you have a final trick bit - Estrecho de le Maire - strait with strong currents and big badly shaped waves, and you can turn right into the beagle and you can mostly day hop between decent anchorages
estarzinger
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From the Pacific - there are two options - down the coast or a big loop out to polynesia and around the big stationary high and back in at Chile. This later is quite long sea distance, but with favorable conditions and some really nice stops which most cruisers doing the pacific dont get to see. The last leg is the only potentially difficult part, several thousand miles into puerto montt in increasing difficult southern weather. This is a passage where it is useful to be good at weather routing - We did some nice clever stuff. The down the coast run has some really nasty against the current and wind sections, and the harbours and countries are not the most hospitable. We much preferred to do long ocean work, so we never did the down the coast and I cant speak to its details much except everyone we know who did it said 'never again'.
The advantage for the pacific entry are two fold. One is it is downwind down the channels from there, which is a ton easier than north bound. The second is that you start at the easer end of the channels so you can get your feet wet and feel you way into the new learning experience. When you enter from the atlantic you are thrown immediately right into the very cold deep end.
We did two south bound trips and one northbound. Patagonia is a bit of a shock if you think you are an expert experienced cruiser, because it really is a whole different level. It is difficult for most people to fit into their cruise plan, but I always suggest for people to try to make two trips in the chanels because the first one will be stressful as you are learning the ropes and the 2nd one you can relax a bit and enjoy the experience.
The advantage for the pacific entry are two fold. One is it is downwind down the channels from there, which is a ton easier than north bound. The second is that you start at the easer end of the channels so you can get your feet wet and feel you way into the new learning experience. When you enter from the atlantic you are thrown immediately right into the very cold deep end.
We did two south bound trips and one northbound. Patagonia is a bit of a shock if you think you are an expert experienced cruiser, because it really is a whole different level. It is difficult for most people to fit into their cruise plan, but I always suggest for people to try to make two trips in the chanels because the first one will be stressful as you are learning the ropes and the 2nd one you can relax a bit and enjoy the experience.
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Panoramix
Super Anarchist
Keel stepped is the last thing you want offshore as it breaks the cardinal rule of making your best to keep the water out in all conditions. I would make an exception for a freestanding mast as it becomes a tradeoff between robustness and an extra hole in the roof!
estarzinger
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I think perhaps just a tiny bit of exaggeration. -_-
Honestly either (keel or deck) is perfectly fine if they are done properly. Just some trade-offs and compromises.
You can plug (in various different ways) the inside of a keel stepped mast at the partners.
I personally lean toward keel stepped . . . but would be just fine with properly done deck step.
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KC375
Super Anarchist
Without my quite understanding it at the time our house – organized by my brothers with parental support - was the first stop/stay in Canada for a good number of draft dodgers. There were always just a lot of long haired poorly shaven young men around for a few years. At least at first I was still young enough to believe what my elder brothers explained about draft dodgers – eventually I became increasingly skeptical that American’s couldn’t chink their homes and couldn't find central heating any closer than Montreal...
By the time the next wave of Vietnam relocations arrived I understood what it meant to be boat people – and I was old enough to appreciate the more interesting food that started making to the dinner table. (We had a stupidly big house, and well my parents were just like that).
Panoramix
Super Anarchist
OK, the last thing I would want...
I know that keel stepped makes sense on a racing boat as the first spreaders can be higher up but there is a reason why deck stpped is prohibited on IMOCAs...
KC375
Super Anarchist
Initial positioning is everything.
There was no ambiguity about why I had my last prolonged delay in secondary.
The pleasant man from CBP wished us a nice Thanksgiving to which my overly woke eldest explained how genocide and occupation was nothing to be thankful for but rather an unending sign of white privilege and exploitation.
The nice man from CBP and his supervisor kindly gave my daughter and I some extended quiet time together in a windowless room so I could explain to her that she did not need to share her world views with everyone she met.
Payback came a few weeks later early on New Year’s day. My middle one does enjoy a party, whic does not combine well with an early morning car trip the next day as she gets motion sick. At the same time as I rolled down the window for the nice border lady to question my daughter – the projectile vomiting started. Fortunately the CBP officer was remarkably agile and avoided the incoming. Documents returned without review and waived through with no further dialogue.
