Oyster Problems?

[chris95040]

Originally Posted by barnakiel

I will disagree with the view that grounding is a norm in the Caribbean or in the Pacific.

Well, up here, I know of one sailor who used to make his way through Narragansett Bay like it was a pinball machine.



Earlier I think Dockhead was making a reasonable point that a good "cruising" vessel should probably be designed to not kill it's new owners if they happen to follow the same learning curve i did...

But yeah, racing/specialty/whatever boats notwithstanding.

[Muckle Flugga]

Originally Posted by barnakiel

I will disagree with the view that grounding is a norm in the Caribbean or in the Pacific.

We have visited Caribbean 2003, 2007 and 2012, we have also crossed Pacific from Panama to Australia. We have not grounded there once nor have we witnessed first hand any grounding incident.

Caribbean is nearly all deep water almost all the way to the (often tall and conspicuous) land. Charts are good too. Areas with less water (e.g. the Bahamas) ask for a special craft. And again, tidal range is relatively small. Why should one ground their boat then.

Pacific is deep water and eyeball where shallows. Why should anybody ground their boat there.

We may differ in our definitions of the word 'norm'. But to me "navigators" who take grounding as a norm are not the sort of people who should inspire the rest of the sailing crowd.

b.

I did not say grounding was the "norm" in the Caribbean or Pacific. What I did say is that it is a normal occurrence in adventure cruising, that is specifically cruising in waters with poor to nonexistent charting. It is not the case that "charts are good" in all areas of the Caribbean. There are large areas where they simply do not show details of hydrography at all, and many areas where they are several score years out of date, at the very least. I am surprised you did not notice that. Of course no one is going to go aground interisland in the EC, as it is oceanic depths, but among the very extensive reefs around Barbuda? Or the massive system to the West of Statia? Both systems have almost no correct charting of specific coral heads or zones, and indeed I have anchored dead on supposedly charted coral heads, but actually in broad stretches of lovely sand, deep within both systems. Each also has dynamic and perforce uncharted sandwaves and sand bars. There are many areas such as that. Your assertion that "the Caribbean is nearly all deep" is neither really true nor really relevant, as obviously nobody grounds a boat in more than a kilometer of water! There are many areas where it is both shallow and VERY far from correctly charted. There is an area of perhaps a quarter square kilometer off SW St. Kitts which is charted to more than 100m, that I found to be less than 20. I questioned my instruments, until I got the lead line out… It corresponds with an area noted on the charts for "discoloured water", and I suspect that it is a new volcanic peak rising, and that the hydrography there is likely more than 100 years out of date.

The only two times I touched bottom in half a decade in the Caribbean were both in harbour environments, in one case for example in Le Marin, in an area which was charted to 17 meters, but which had thoroughly silted and was in the process of being redredged. There was no indication of that process at the time, but I found out about it as I ran into the dredgeline, going from 15 to 2 meters in 1.5 seconds. The water was turbid and there was no way to determine depth ahead by "eyeball navigation". This latter is also true of many areas of the pacific. Sure there are plenty of zones where it is possible to see coral heads clearly, but many lagoons it is impossible, and less than 5% of the Tuamotu lagoons are even close to adequately charted, with the overwhelming majority of areas completely uncharted. Tonga likewise and many other similar places.

In 23,000 miles in the Indo Pacific in the past couple of years I have not grounded even lightly, but I have narrowly avoided it on a number of occasions, including having to throw her hard astern because the forward looking sonar showed sharp shallowing to 1 meter dead ahead in the Southern Vavau archipelago, despite being charted to not less than 18 meters. That was right after passing a small ISLAND which did not appear on any chart! The water was likewise turbid and impossible to see through. I have known a good few excellent sailors who went aground in the Pacific, and it is as much fortune as vigilance and good seamanship that I was not one of them. The same applies to yourself, I would warrant, unless you consider yourself perfect in some sense?

I am particularly unimpressed by your claim that "Pacific is deep water and eyeball where shallows." This is simply flatly untrue in very many locations. Ever tried to dive in the bays in Nuku Hiva? In the Pacific alone, there are THOUSANDS of anchorages and lagoons where turbidity makes your statement exactly the kind of idea which causes people to go aground through overconfidence!

Dockhead's points are the correct ones on this score: you may be the best driver in the world, but you are still foolish if you refuse to wear a seatbelt. Things happen, and if you rely on good luck in areas where charts are poor and help is beyond remote, rather than a strong boat and keel that can withstand grounding…

I attach a few photos for your amusement. My favorite is of my being anchored up a hill in the Komodo archipelago, as you can see on both CMap and Navionics charts (with radar overlay). On the former I marked it with a joke wreck and it is denoted "Event 0753". I attach a photo of the boat in its true position there as well, shot from roughly the same distance inland as the charts would have had me…

[jmaja]

Originally Posted by Polux

The standard Pogo has a swing keel and to hit a rock with a 1.2m draft one has to be a moron or to be completely devoid of any care.

If you sail in waters where grounding is more likely, you could ground quite easily with a 1.2 m draft. I know very many people who have done that here and I don't consider most of them morons. You don't see the 1 m ground until you hit it so what's the difference between a 3 m and 1.2 m draft. When you are about to sail over a rock your chances to not hit it are bigger with 1.2 m draft, but eventually you will find a shallow enough rock.

Normal sailing position is 3 m draft for that Pogo. I don't know how it would survive a grounding with the keel hitting the hull. I don't know either how well the keel swing mechanism tolerates grondings when the keel is already up.

A swing keel can be very good protection against groundings, but it needs a damping system to limit the swing of the keel like this boat has:

https://www.youtube.com/watch?v=TGWjmboWcYc

[neilpride]

The Pogo have a fuse in the swing keel mechanism to let the keel swing in a collision I guess, I'm not sure, wonder if the rudders swing to?

[Dockhead]

Originally Posted by Polux

. . . to hit a rock with a 1.2m draft one has to be a moron . . .

It's hard for me to come up with a polite comment to this -- foolish and arrogant statement. But I'll try

Most of the world's waters are not like the steep-to Mediterranean. There are rocks, coral heads, drifting sand banks, and unsurveyed bottoms, everywhere, even in civilized, populated places.

Hydrographic surveys are not primarily intended for pleasure vessels, but for normal shipping. It is EXACTLY the boat with a small draft, like this, which is MOST at risk of grounding, because waters at those depths are not surveyed thoroughly, practically anywhere, and are anyway subject to constant changes due to the action of waves and currents. A 3 meter sounding might have some substance in many places, but a 1.5 meter sounding -- if it even exists -- has little substance, because of these factors. A shallow draft allows you to get into places others can't go, but these are the very places which are the most risky. I have no doubt that if you analyzed the incidence of grounding and graphed it against the draft of the boat which was grounded, you will find a high correlation between draft and propensity to ground, with shallow draft boats being grounded far more often than deep draft boats.


I spent decades sailing in SW Florida in a boat with a draft of 1.4 meters, and we went aground constantly -- at least a couple of times every year. I guess I'm a "moron", according to Polux. Not once, as far as I can recall, in a place where there should not have been enough water according to the chart. The water is very shallow all around that very low coastline, depths constantly changing, sand banks can form as a result of one small gale, which can turn a 2 meter channel into a 1 meter one overnight. Plenty of passes had depth of only 1.5 or 1.6 meters and you just squeaked through with just the right tide, or you couldn't go there at all. That's just the nature of sailing in places like that, and it's not the only place like that in the world. According to Polux, not just me, but the entire SW Florida sailing community are "morons". It was considered a remarkable achievement among SW Florida sailors to get through a whole year without a grounding.

I've touched the bottom four times in my present boat in 6+ years and 15 or 20k miles. Once in Dartmouth Harbor, just off the town quay, where there should have been more than 3 meters of water according to the chart. The harbormaster came by in his RIB and said "so you found our sand bank, eh?". Once in Dunkirk at dead low tide, also one or two meters from the dock, at dead low tide, at night, after a long passage of two days and nights. The depth was more than one meter less than marked on the chart -- the harbor was silting up. Once in a gale and at night, leaving Bologne Sur Mare at low tide. This was the most frightening one. The only grounding I have ever had in my life due to an error in pilotage. We threw out the kedge and got off in about 10 minutes as, thank God, the tide was rising. The last time was when I hit that uncharted rock in Finland. Many, many other cases I have avoided just by pure luck, like the rock awash at the edge of the fairway near Gogland, unmarked and uncharted, and right where I wanted to leave the fairway. If that had been at night? Or the rock not barely awash, but 60cm below the surface?

I spent some time cruising the Caribbean in chartered catamarans. The shallow draft was really useful as there are many desirable bays and passes with less than 2 meters of water in them. I never touched the bottom, but I'm sure I would eventually have done so, given enough time. Variations from the charts were everywhere, especially in the Windward Islands, and most coral heads were neither charted nor marked, often in unexpected places, and being hard and sharp would rip the keel off a lightly built boat.


Charts are not infallible, and become less and less infallible, the further you get away from areas surveyed for shipping, and still less and less infallible, eventually to the point of uselessness, when you sail away from civilization. I've never known a sailor with more than a year of experience, who had never been aground. Therefore, in my opinion, the normal kind of cruising boat ought to be designed to survive most groundings, without structural damage.


There may be some superman, somewhere, whose skills are so brilliant -- maybe he has x-ray vision, to see below the surface, day or night -- that he can be completely confident that he will never go aground. I've never met such a superman, except on internet fora.

[Polux]

Originally Posted by Dockhead

Nor is crashing a car the norm, but it makes sense to be prepared for it, to the extent it is rational, in case it happens. Seat belts? Air bags? Crash-tested structure? Absolutely, even if you've driven a million+ miles without an accident, as I have.
...

This has nothing to do with what you are defending regarding keels to be able to sustain hard groundings with any sort of damage.

That would correspond to cars being able to crash without sustaining any damage.

That is not the case and quite contrary modern cars are designed to destroy themselves on an absorbing way when crashed. Modern cars will sustain a lot more damage on a crash than 40 year old cars but the passengers will have a much better possibility of not sustaining damage.

As it was already pointed out modern keels are designed not to fall out even when sustaining an heavy grounding and the interior structure is designed to absorb the shock while sustaining some damage. That makes the shock less violent, protecting better the crew and giving more possibilities of not losing the mast.

As it was already pointed out very few modern boats are lost after a hard grounding and they can be sailed to a shipyard for repairs.

[Polux]

Originally Posted by Dockhead

It's hard for me to come up with a polite comment to this -- foolish and arrogant statement. But I'll try

Most of the world's waters are not like the steep-to Mediterranean. There are rocks, coral heads, drifting sand banks, and unsurveyed bottoms, everywhere, even in civilized, populated places.

Hydrographic surveys are not primarily intended for pleasure vessels, but for normal shipping. It is EXACTLY the boat with a small draft, like this, which is MOST at risk of grounding, because waters at those depths are not surveyed thoroughly, practically anywhere, and are anyway subject to constant changes due to the action of waves and currents. A 3 meter sounding might have some substance in many places, but a 1.5 meter sounding -- if it even exists -- has little substance, because of these factors. A shallow draft allows you to get into places others can't go, but these are the very places which are the most risky. I have no doubt that if you analyzed the incidence of grounding and graphed it against the draft of the boat which was grounded, you will find a high correlation between draft and propensity to ground, with shallow draft boats being grounded far more often than deep draft boats.


I spent decades sailing in SW Florida in a boat with a draft of 1.4 meters, and we went aground constantly -- at least a couple of times every year. I guess I'm a "moron", according to Polux. Not once, as far as I can recall, in a place where there should not have been enough water according to the chart. The water is very shallow all around that very low coastline, depths constantly changing, sand banks can form as a result of one small gale, which can turn a 2 meter channel into a 1 meter one overnight. Plenty of passes had depth of only 1.5 or 1.6 meters and you just squeaked through with just the right tide, or you couldn't go there at all. That's just the nature of sailing in places like that, and it's not the only place like that in the world. According to Polux, not just me, but the entire SW Florida sailing community are "morons". It was considered a remarkable achievement among SW Florida sailors to get through a whole year without a grounding.
....

What you say is obvious regarding chats not to be accurate for depths under 2.0m. In fact in what concerns me even in well charted places I extend that natural lack of accuracy to anything under 3.0 or 4.0m.

Regarding being grounded with a 1.2m draft not be not very bright regarding sailing skills, as you know we were talking about HARD GROUNDINGS, and having a swallow draft does not mean that you use it on an irresponsible way, not taking into account that small depths are never precisely charted.

Even on well charted waters even if the chart does not indicate any rocks I always approach an anchorage very slowly, particularly when depths are under 10 m. On depths under 6m I go at about 1k and I always circle around to see if there is space for the boat to turn on the anchor without obstructions.

Now, I don't want to give you the impression that on the anchorage I am one of those boats that stay always very far away from land, quite the contrary, but I do that very carefully and if near land I always check diving, if the boat has really a good clearance and some times I had to change the boat because I was not satisfied.

So, I would say that with a boat with 1.2m draft I (or any good sailor) would not have any hard groundings. I doubt that even with mine, that has 2,3m draft, the possibility of that happen is hugely remote. It is all a question of good seamanship and care and approaching depths under 10m at small speed.

[neilpride]

Well, definitely with that logic you are kicking in the ass places like Bahamas, a wonderful place to be and enjoy, and many more where the depths are shallow,,, I will say you are a deep water chart sailor, but as you know, a big percentage of cruisers don't want to miss those places.... and 2,3 draft is not a impediment to sail those waters,,,

[Dockhead]

Originally Posted by Polux

What you say is obvious regarding chats not to be accurate for depths under 2.0m. In fact in what concerns me even in well charted places I extend that natural lack of accuracy to anything under 3.0 or 4.0m.

Regarding being grounded with a 1.2m draft not be not very bright regarding sailing skills, as you know we were talking about HARD GROUNDINGS, and having a swallow draft does not mean that you use it on an irresponsible way, not taking into account that small depths are never precisely charted.

Even on well charted waters even if the chart does not indicate any rocks I always approach an anchorage very slowly, particularly when depths are under 10 m. On depths under 6m I go at about 1k and I always circle around to see if there is space for the boat to turn on the anchor without obstructions.

Now, I don't want to give you the impression that on the anchorage I am one of those boats that stay always very far away from land, quite the contrary, but I do that very carefully and if near land I always check diving, if the boat has really a good clearance and some times I had to change the boat because I was not satisfied.

So, I would say that with a boat with 1.2m draft I (or any good sailor) would not have any hard groundings. I doubt that even with mine, that has 2,3m draft, the possibility of that happen is hugely remote. It is all a question of good seamanship and care and approaching depths under 10m at small speed.

Good seamanship and care are needed in all aspects of our sport.

Many groundings are caused by the lack of good seamanship, or lack of care, or both. But not all; possibly not even most. It is an unjustified assumption you make, which could have even fatal consequences, that your seamanship and standards of care are so superior that you will never go aground anywhere. The sea does not lightly forgive such hubris.

My guess is that you are universalizing your own experience in your own cruising grounds, and misapplying it to the rest of the world. I have never, myself, come close to grounding in the Mediterranean. The shores there are -- everywhere I have sailed -- steep-to with lots of depth right up to the edge of the shore. There are no tides to speak of. The charts are excellent, even in parts of the Med we think might be less civilized, like Turkish and Croatian waters. There are no shallow passes which require taking chances, to get through. I haven't seen much in the way of shifting sand bars.

If my primary cruising grounds were the Med, in view of all this, where light wind sailing ability is important, I think I might also want an ultra high performance keel, a very light boat, with a large SA/D. Never far anywhere from rescue services, certain risks are reasonable to take in the keel design.

Sailing in other places, especially more remote, and/or higher latitudes, the considerations may be completely different.


Strength of the keel and its attachment is relevant not just for the sake of avoiding damage. Certainly we want to avoid any damage at all, in common groundings, to the extent it's possible without being unreasonably expense or ruining the boat's performance. But keel damage in a grounding is often not just a matter of an expensive repair, it often also causes flooding, and can result in sinking and loss of life. If the keel becomes detached, as in the case which is the subject of this thread, capsizing and deaths can result.

All things concerning boat design are a compromise, but this is one area where for most sailors, the optimum design will go pretty far in making other compromises, for the sake of strength. At the risk of boring everyone by repeating it, I would never buy myself, nor recommend to any of my friends, a boat which has a keel which is not strong enough to withstand a pretty violent grounding. In my opinion, such a keel is appropriate only for hard core racers or performance nuts, sailing in very controlled conditions, or in cruising grounds where grounding is extremely unlikely.

[Dockhead]

Originally Posted by Muckle Flugga

In 23,000 miles in the Indo Pacific in the past couple of years I have not grounded even lightly, but I have narrowly avoided it on a number of occasions, including having to throw her hard astern because the forward looking sonar showed sharp shallowing to 1 meter dead ahead in the Southern Vavau archipelago, despite being charted to not less than 18 meters. That was right after passing a small ISLAND which did not appear on any chart! The water was likewise turbid and impossible to see through. I have known a good few excellent sailors who went aground in the Pacific, and it is as much fortune as vigilance and good seamanship that I was not one of them. The same applies to yourself, I would warrant, unless you consider yourself perfect in some sense?

If a rock is not shown on a chart, and not marked with a danger mark, then other than the rare case where you just happen to see it in time, the only way to avoid it is by pure luck. How often is the water clear and the sun shining? What do you do at night? What if you don't happen to be staring right over your bow at the moment? It's important to keep a sharp visual watch, but it's not a panacea, particularly not what concerns hitting uncharted rocks.


Bit of thread drift, but I am fascinated to hear that forward looking sonar has actually saved you from a grounding -- first such story I've ever heard. I have a FLS set on my boat which I have stopped even turning on, after years of no useful data from it. I wonder if your set is better, or you just know something, I don't, about interpreting the data?

Originally Posted by Muckle Flugga

I attach a few photos for your amusement. My favorite is of my being anchored up a hill in the Komodo archipelago, as you can see on both CMap and Navionics charts (with radar overlay). On the former I marked it with a joke wreck and it is denoted "Event 0753". I attach a photo of the boat in its true position there as well, shot from roughly the same distance inland as the charts would have had me…

The entire Sea of Cortez is like that. The coast is in some places up to a mile from where the chart says it is. To imagine that charts are infallible, and are a completely solution to hitting rocks, is a very grave error. In waters too shallow for regular shipping, and which have therefore not been surveyed to nearly the same extent, I daresay there are more uncharted, than charted rocks, at least once you get outside the First World.

[Polux]

Originally Posted by Exile

It seems like it's all about margins -- performance, comfort, safety. But if you're not an educated buyer, it would be difficult to make a reasoned decision, especially if you were relying merely on the bare minimum standard -- the EU/CE Classification Rating that is.

Yes I agree with you. There is talks about making another RCD category above the maximum existing one. It exists that category in what regards racing offshore or in what regards professionally charted boats in UK.

Does not mean that the one that exists will be modified in what it stands for, just as you say, a bigger safety margin.

The reason that lead me to have an interest in boat design was precisely that, to be an educated buyer but I would never guess what you have to learn to be just that

As this Oyster case shows traditional solutions are not necessarily safer solutions even if most tend to look at the past to be assured that they are "proven" and safer design solutions.

There is also a tendency to mix luxury in what regards finish and interior quality with sound quality in what regards structural solidness and seaworthiness. Again this case is a good example.

[barnakiel]

Originally Posted by Muckle Flugga

I did not say grounding was the "norm" in the Caribbean or Pacific. What I did say is that it is a normal occurrence in adventure cruising, that is specifically cruising in waters with poor to nonexistent charting.

(...)

I attach a few photos for your amusement. My favorite is of my being anchored up a hill in the Komodo archipelago, as you can see on both CMap and Navionics charts (with radar overlay). On the former I marked it with a joke wreck and it is denoted "Event 0753". I attach a photo of the boat in its true position there as well, shot from roughly the same distance inland as the charts would have had me…

Yep. I can hear you. We agree that grounding is not a norm, not here nor elsewhere. It is an unwelcome event, and boats advertised as as "go anywhere" should be designed and build to allow for this fact.

And charts ... too bad for us when we think that if something zooms in endlessly on a digital plotter it is indeed a coastal chart we have. In fact, it is not; it is just an overzoomed general chart, neither intended nor holding details required for coastwise exploration.

Should digital charting companies sell us such general charts as coastal charts, they would be liars. (But we know they are not, and the problem is not in their charts but in how we mis-/use them).

So it seems a very simple thing to enact: groundings happen, some boats are designed and built to take them, others are not. When in area with only general chart coverage, walk softly (and wear boots, not flipflops)

An oyster flip flop? (pun unintended) ;-)

b.

[Polux]

Originally Posted by Muckle Flugga

I did not say grounding was the "norm" in the Caribbean or Pacific. What I did say is that it is a normal occurrence in adventure cruising, that is specifically cruising in waters with poor to nonexistent charting.....
The only two times I touched bottom in half a decade in the Caribbean were both in harbour environments...

In 23,000 miles in the Indo Pacific in the past couple of years I have not grounded even lightly...good few excellent sailors who went aground in the Pacific, and it is as much fortune as vigilance and good seamanship that I was not one of them. The same applies to yourself, I would warrant, unless you consider yourself perfect in some sense?

....exactly the kind of idea which causes people to go aground through overconfidence!
.…

It seems to me that on the essential we agree. Hard groundings are not the norm and most hard groundings are due to overconfidence that in my book equals bad seamanship.

I also agree that in what regards adventure cruising and sailing on mostly uncharted waters it makes all sense to have a boat specially adapted to it, a steel or aluminum boat preferably with a centerboard or a swing keel but it is also true that I know of several cases of navigation on those waters, for extensive periods, with very common boats like a Bavaria 44 or a First 40.7, that circumnavigated by high latitudes, exploring very poorly charted waters without any problem in what regards hard groundings or whatsoever.

[Polux]

Originally Posted by jmaja

If you sail in waters where grounding is more likely, you could ground quite easily with a 1.2 m draft. I know very many people who have done that here and I don't consider most of them morons. You don't see the 1 m ground until you hit it so what's the difference between a 3 m and 1.2 m draft. When you are about to sail over a rock your chances to not hit it are bigger with 1.2 m draft, but eventually you will find a shallow enough rock.
....

Again, we were talking and I was talking about hard groundings.

When you have a rock at 1.2m deep, surely around you have nearby chart markings pointing to 3, 4 or 5 m deep if you really want to proceed on that course and don't want or can to look for a deeper passage, you will do so (I hope) very carefully and at slow speed so even if you touch a rock you will touch it not in a hard way, nothing that can be called a hard grounding.

As you say, 1.2m draft only decreases the likeness of hitting a rock passing over a badly charted place. It can be charted at 4 or 5m but the likeliness of having there a badly charted 1.2m rock over a 3 or 2m rock is much smaller.

Anyway in what concerns me and hard-groundings on decently charted areas, and that is where 95% of the boats sail, makes no sense. I only go fast over 10m depth and sail very carefully, at slower speeds on lesser deep waters (unless I know the place) and that practically excludes the possibilities of a hard grounding on those waters.

On those waters with less than 10m you can have badly charted waters, but over 10m I never found more than a 3 or 4m difference and just on the borderline 10m line. That is a safety margin more than enough for a medium sized sailboat, even with a deep draft.

Probably that is different for someone that races and want to take shortcuts, but the danger comes with the territory, I mean racing and accepting more risks.

[sailorboy1]

Maybe this is thread drift, but:

It is my understanding the keel that ripped off the hull of the Oyster in question never experienced any grounding. Probably the only example of a keel just falling off a boat with no "help" ever out of all the stories of lost keels I can recall.