Oyster Problems?

[Polux]

Originally Posted by jmaja

What makes 825 a light boat in your opinion? I find it very heavy and can't understand where they put all that weight, if the skin is only 15 mm in the keel area.

10 tonnes heavier than Swan 86 from 1988 or 15 tonnes more than the S&S 76. Current Swans and many others are clearly lighter than those two.

The Swan 86 is a narrower boat with a smaller transom and smaller LWL and has a much smaller and more "spartan" interior. The difference of weight is about 6000kg, being the Oyster heavier.

There are many modern performance cruisers of that size much lighter than the Oyster sailing for many years without any problem. when I talk about the Oyster being lighter I refer previous Oyster models. It seems they make it lighter but build it the same way they built the heavier ones, I mean same type of keel, same type of keel structure, same type of hull, same materials. That would give a lighter boat but also a less strong boat.

Have a look at this post where I compare the D/L of several Oysters with the one of the Polina Star that is a 825 lengthened to 90ft.

http://www.cruisersforum.com/forums/...ml#post1971901

[barnakiel]

If only boat builders cared to read our mumblings!

Not to say there is any wisdom here nor lack of thereof. Simply, a lot of opinions and reading thru them they could find where they went wrong?

BTW I was wondering if perhaps Pollina Star had been (post launch) dried? Perhaps the lamination schedule (as seen in pictures) was so weak that she took damage while peacefully resting on her keel in a boatyard (say while taking that extra coat of antifouling paint before a passage) ???

I know that some pure racing boats are not placed on their keels but rather hung in the slings for that.

How does all this fuss affect s/h Oyster prices?

b.

[JPA Cate]

Originally Posted by barnakiel

How does all this fuss affect s/h Oyster prices?

b.

Have to wait and see, of course, but I would think the older ones value would not be much affected.

[Dockhead]

Originally Posted by barnakiel

. . .

How does all this fuss affect s/h Oyster prices?

b.

Hoping to buy, Barn?

There's always someone looking to profit from someone else's misery

[transmitterdan]

Originally Posted by Ann T. Cate

Have to wait and see, of course, but I would think the older ones value would not be much affected.

May even increase the value of the older ones...

[Kenomac]

The only buzz and concern regarding Oyster prices and keels seems to be taking place on cruising forums. Not much of any talk on the Oyster owners forum.

[JPA Cate]

How many members does the Oyster Owners Forum have?

If I were going to be sarcastic, which I surely am not, I might guess 2, or say one less, since the sinking of the Polina Star III. But it does make me wonder if most Oyster owners are forum joiners, anyway?

Ann

[Muckle Flugga]

Originally Posted by 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.

Well perhaps you can't recall very many? The Match 42s, the Fast 42 among a fair few others of the pedestrian variety and among the super/race yachts: Rambler 100, Drum, Hugo Boss, Exide Challenger are prety famous examples, and among the many where the keel very nearly fell off unassisted, Movistar, and the ENTIRE Clipper fleet in the 2006 Clipper RTW race, among many others. How many disappearances in the Oceans are due to sudden unassited catastrophic failure is difficult to know, but I am pretty absolutely it is more than one.

[Muckle Flugga]

I would like to add a note concerning the debate regarding grounding. Grounding is not the only source of impulse to a yacht keel that can be considered to be structurally significant in weak designs. Collisions with submerged objects are at least as significant if not more so and signally occur without the slightest warning, seamanship being completely out of the equation as a factor. Further, they commonly occur far offshore where a vessel must perforce sail on hundreds or thousands of miles to ensure the safety and survival of the crew. A great deal of air has been expended elswehere on the subject of containers. I am somewhat sanguine about the true prevalence of this risk, however in such an encounter the forces would be comparable to hitting solid rock at hull speed. Whatever the true risk of container strike, whale strikes are indeed common, and the forces imparted by the tail of a startled and panic diving whale can far exceed a hull speed collision with rock. Collision with semisubmerged logs, treetrunks, or even large plastic containers at speed will impart immense forces to a keel structure, easily comparable to a hard grounding. Further, it is the case that such impacts commonly occur at maximum hulls speed, which speed is likely to be faster in the more lightly built "cruiser racer" type structures, that indeed Oyster was going for in this poorly thought out design.

Polux in particular has expended a lot of words trying to diminish the commoneness or severity of grounding incidents. What his words in fact do is underscore the danger of collisions with whales and submerged objects for boats whose structures are now admittedly by all and demonstrably severely to fatally weakened by these kinds of impulses. In such circumstances, there is a 100% certainty of hundreds or thousands of miles further strong forces being exerted on the keel before even an effective assessment of the damage such an impact has imparted to these underbuilt, difficult to examine structures.

It is even possible, perhaps even likely, that such an event was what finally wrecked the keel structure of the Cheeki Rafiki. In the MAIB report the following sequence occurs, taken from communications with the craft as the catastrophe began:

"Wednesday 14 May 2014
1014 – email, from Cheeki Rafiki
‘position update at 1000ut 37 00N 052 05W 24hour run 176miles...just hit a big
wave hard and it fixed the stereo.’ [sic]

Thursday 15 May 2014
2022 – email, from Cheeki Rafiki
‘we have been taking on a lot of water yesterday and today. today seems worse i think stbd water tank has split so that is drained checked hull and sea cocks for damage but cant see any. i will go for a swim when weather improves in about 24 hours we are currently monitoring the situation horta is 900 miles away. our position is 38 38N 048 59W any thoughts from your end i will check emails in 2 hours’ [sic]"

It seems to me more than possible that the "big wave" that was hit "hard" was not in fact a wave at all, but something rather more solid.

I know I have hit solid objects hundreds and thousands of miles out to sea in thousands of meters of water. I know many others who have too. How would you feel if you did, in the likes of a 40.7, or else in one of these "new style" Oysters? Could you even be sure that the last wave you just fell off with a bang was really a wave after all? Would you wish you were in fact in an "old style" Oyster?

I know I would!

[Muckle Flugga]

Originally Posted by Dockhead

...

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?

...

It was a fairly simple Echopilot set, repeated on to a fairly large colour tv screen visible through the companionway from the helm. These sets are not perfect, and indeed the data are not that easy to interpret, but with practise they can be invaluable in slow pilotage in just this kind of setting. The trick is to develop a way of looking at the many and differently coloured points of return plotted in advance of the vessel as if they were a graphed data set, and to draw a mean line among them, mentally. Broad structures can be fairly clearly seen, and particularly clearly is the field hockey stick like structure of a sudden shallowing. Really that is all you need to see. Sudden shallowing appears clearly and is pretty much unambiguous. In the case I described it was confirmed by the conventional sonar, though fortunately not the keel!

[minaret]

Originally Posted by Muckle Flugga

I would like to add a note concerning the debate regarding grounding. Grounding is not the only source of impulse to a yacht keel that can be considered to be structurally significant in weak designs. Collisions with submerged objects are at least as significant if not more so and signally occur without the slightest warning, seamanship being completely out of the equation as a factor. Further, they commonly occur far offshore where a vessel must perforce sail on hundreds or thousands of miles to ensure the safety and survival of the crew. A great deal of air has been expended elswehere on the subject of containers. I am somewhat sanguine about the true prevalence of this risk, however in such an encounter the forces would be comparable to hitting solid rock at hull speed. Whatever the true risk of container strike, whale strikes are indeed common, and the forces imparted by the tail of a startled and panic diving whale can far exceed a hull speed collision with rock. Collision with semisubmerged logs, treetrunks, or even large plastic containers at speed will impart immense forces to a keel structure, easily comparable to a hard grounding. Further, it is the case that such impacts commonly occur at maximum hulls speed, which speed is likely to be faster in the more lightly built "cruiser racer" type structures, that indeed Oyster was going for in this poorly thought out design.

Polux in particular has expended a lot of words trying to diminish the commoneness or severity of grounding incidents. What his words in fact do is underscore the danger of collisions with whales and submerged objects for boats whose structures are now admittedly by all and demonstrably severely to fatally weakened by these kinds of impulses. In such circumstances, there is a 100% certainty of hundreds or thousands of miles further strong forces being exerted on the keel before even an effective assessment of the damage such an impact has imparted to these underbuilt, difficult to examine structures.

It is even possible, perhaps even likely, that such an event was what finally wrecked the keel structure of the Cheeki Rafiki. In the MAIB report the following sequence occurs, taken from communications with the craft as the catastrophe began:

"Wednesday 14 May 2014
1014 – email, from Cheeki Rafiki
‘position update at 1000ut 37 00N 052 05W 24hour run 176miles...just hit a big
wave hard and it fixed the stereo.’ [sic]

Thursday 15 May 2014
2022 – email, from Cheeki Rafiki
‘we have been taking on a lot of water yesterday and today. today seems worse i think stbd water tank has split so that is drained checked hull and sea cocks for damage but cant see any. i will go for a swim when weather improves in about 24 hours we are currently monitoring the situation horta is 900 miles away. our position is 38 38N 048 59W any thoughts from your end i will check emails in 2 hours’ [sic]"

It seems to me more than possible that the "big wave" that was hit "hard" was not in fact a wave at all, but something rather more solid.

I know I have hit solid objects hundreds and thousands of miles out to sea in thousands of meters of water. I know many others who have too. How would you feel if you did, in the likes of a 40.7, or else in one of these "new style" Oysters? Could you even be sure that the last wave you just fell off with a bang was really a wave after all? Would you wish you were in fact in an "old style" Oyster?

I know I would!

Excellent! Hear, hear!

[Muckle Flugga]

Originally Posted by jmaja

...
It's good question to ask how hard grounding a boat should be able to handle. I don't think there are many boats that can handle 7 knots hard groundings without damage, but also I don't think there should be any boat loosing its keel in it. By hard I mean hitting a steep rock (granite or other hard, not sand or loose small rocks) and bouncing back from it. It certainly is not at all easy to desing and make such a keel struckture without loosing performance and not making the boat very expensive.

I don't think a First 40.7 not having damaged from previous groundings would loose its keel in the hard grounding described above.

There are plenty of boats which could survive such a grounding with minimal or no damage at all. I mean, steel long keelers are an obvious example but really there are many from almost any material, even wood, if built strongly enough.

With regard to your final statement, you are simply not noticing that the "previous grounding" was in fact subject to some repair, followed by simple sailing, or possibly a collision with a submerged object. Frankly that is the whole point of what those of us who are skeptical of such designs are saying: a true oceanic cruising boat should not be suspect or critically weakened in its keel structure by hard groundings, much less light ones or collisions with submerged objects because the MUST be able to withstand such incidents and nonetheless continue the voyage in order to ensure the safety of the crew
. Further, your idea that a 40.7 would survive a hard grounding provided it hadn't had "previous groundings" is strictly illogical. The hard grounding referred to by Polux in this thread (not the CR incidents, which were light) involved violent and repeated bashings against rock! Which means it was a whole series of hard groundings in one incident. So how are you trying to divide the cake? Your argument makes no sense at all. How many "groundings" would a 40.7 survive? One very hard one? A series of light ones? How many in the same incident? How much hard beating subsequently equates to a further grounding, in your opinion? Given that the report states that even very light groundings can cause structurally significant debonding in this design that is unnoticeable to the crew, how could you even assess that were you actually aboard?

The fatal loss of the keel of the "Hooligan" occurred after only two low speed groundings on very soft substrates, from which the vessel sailed immediately onwards, ultimately to its doom, and during the act of merely sailing.

[Kenomac]

Originally Posted by Ann T. Cate

How many members does the Oyster Owners Forum have?

If I were going to be sarcastic, which I surely am not, I might guess 2, or say one less, since the sinking of the Polina Star III. But it does make me wonder if most Oyster owners are forum joiners, anyway?

Ann

More than 600 members.

[Kenomac]

Originally Posted by sailorboy1

Maybe you need a refreshed for when I told you that the previous owner had asked about the boats keel being loose before selling it to you. It didn't suddenly come loose on you.

But you spin it however you want.

.

I don't recall you being a participant during the purchase of our previous boat six years ago?.

BUT FYI once again, the previous owner did inquire online to the Hunter owners forum following the sale and during the discovery as to the extent of the repairs needed at the KKMI shipyard. You see.... my buyers broker was smart enough to hold the seller responsible for the cost of the keel repair when it was determined by the shipyard after weeping was discovered during survey. Which turned out to be THE HUNTERS KEEL HAD COME LOOSE.

Sailorboy... You have the timeline all screwed up.

Maybe someday.... when you finally get away from your computer screen and away from your mooring can, you'll finally be able to focus your mind on things other than someone else's business... and begin enjoying your life.

Meanwhile, quit making stuff up. This has all been explained to you several times before, pictures were even provided... Let it go.

Please... Go sailing.

[jmaja]

Originally Posted by Polux

There are many modern performance cruisers of that size much lighter than the Oyster sailing for many years without any problem. when I talk about the Oyster being lighter I refer previous Oyster models. It seems they make it lighter but build it the same way they built the heavier ones, I mean same type of keel, same type of keel structure, same type of hull, same materials. That would give a lighter boat but also a less strong boat.

If you compare current Swan models and Oyster models, 825 seems to be very heavy and some other Oyster are much lighter.

Oyster 825: LWL 21.97 m, beam 6.31 m, draft 3.42 m, displacement 56 tonnes
Swan 80: LWL 22.19 m, beam 6.08, draft 4.0, displacement 36 tonnes

Oyster is almost 60% heavier.

Oyster 625: LWL 17.24 m, beam 5.44 m, draft 2.8 m, displacement 33.5 tonnes.

Swan 66: LWL 17.19 m, beam 5.39 m, draft 3.0 m, displacement 30 tonnes

Oyster is only 12% heavier.

Oyster 545: LWL 14.1 m, beam 4.75 m, draft 2.4 m, displacement 21.3 tonnes

Swan 54: LWL 14.4 m, beam 4.75 m, draft 2.44 m, displacement 22 tonnes

Oyster is 3% lighter.

So it seems that for Swans DLR decreases much more rapidly with inceasing size than for Oysters. Partly that is due to increased used of carbon (no carbon in 54, some in 66, a lot in 80).

If you see lightness as the cause of problem, then there are other Oyster models that should have the same or worse problem.