Very engaging Youtube interview with Dick Beaumont on what makes a Bluewater boat

[jordanbasset]

The Kraken 50 looks an interesting boat and if I won the lottery I would look at it, but for the vast majority of sailors the £800,000 plus price tag makes it an unrealistic option

 

[dom]

The Kraken 50 looks an interesting boat and if I won the lottery I would look at it, but for the vast majority of sailors the £800,000 plus price tag makes it an unrealistic option

Funnily enough I've been vaguely looking at similar boats, albeit a tad bigger.

Just a glance at the Kracken suggests that it wouldn't come close to the cruisy builder I'm currently most attracted to in terms of performance, looks, usability, maintainability, ease of sailing, etc., etc.

 

[Nom de plume]

Dick Beaumont made a very explicit point in the video - he specifically said that the purpose to which the vessel is to be put should first be defined in order that the best design to meet that purpose can sought.

Sales and marketing ploys, IOR, are valid points in themselves but they do miss his overall claim - namely that encapsulated / integral keels and skeg hung rudders are inherently stronger engineering structures than bolted keels and spade rudders - does anybody wish to claim that the opposite is true?

 

[dom]

Dick Beaumont made a very explicit point in the video - he specifically said that the purpose to which the vessel is to be put should first be defined in order that the best design to meet that purpose can sought.

Sales and marketing ploys, IOR, are valid points in themselves but they do miss his overall claim - namely that encapsulated / integral keels and skeg hung rudders are inherently stronger engineering structures than bolted keels and spade rudders - does anybody wish to claim that the opposite is true?

The data suggests that both routes are perfectly fine almost all of the time. Bolt-on keels such as CR's fell off after an owner failed to remedy a serious grounding, and Polina Star 3's fell off even though it was attached to a structural stub.

Also any boat can suffer catastrophic damage following either a collision with an object or structural failure. This is where survivable watertight spaces come into play, and why they are requirement on many racing yacks. The Titanic taught us that!

Kracken's failure to spec these, in my opinion, reveals its entire premise as frankly ridiculous. Worse, it forces the design down a route where sailing ability will be seriously compromised, which is why I for one wouldn't buy one.

Personally, I doubt the brand will last.

 

[Nom de plume]

The data suggests that both routes are perfectly fine almost all of the time. Bolt-on keels such as CR's fell off after an owner failed to remedy a serious grounding, and Polina Star 3's fell off even though it was attached to a structural stub.

Also any boat can suffer catastrophic damage following a collision with something or structural. This is where survivable watertight spaces come into play and why they are requirement on many racing yacks. The Titanic taught us that!

Kracken's failure to have these, in my opinion, reveals its entire premise to be frankly ridiculous. Worse, it forces the design down a route where sailing ability will be seriously compromised, which is why I wouldn't buy one. Personally, I doubt the brand will last.

As an ex submarine engineer I'm pretty familiar with the concept of watertight spaces!
But he was not talking about watertight spaces, IOR, etc. He was stating, quite simply, that for a blue water cruising vessel, an integral keel and rudder arrangement is an inherently stronger engineering solution than bolted-on arrangements - I agree with him on that.
The fact that many (most) bolt on keels do survive is not his point - he is saying that, for that particular purpose, encapsulated / integral is a better solution - it is not the only solution, just simply a better solution.
To disagree with him on that point, one would have to claim that bolted on keels and spade rudders were not just 'satisfactory in the majority of cases' - but were actually a better engineering solution. Personally, I do not think that they are a superior solution, and I've yet go see anyone on this thread demonstrate why they are.

 

[dom]

As an ex submarine engineer I'm pretty familiar with the concept of watertight spaces!
But he was not talking about watertight spaces, IOR, etc. He was stating, quite simply, that for a blue water cruising vessel, an integral keel and rudder arrangement is an inherently stronger engineering solution than bolted-on arrangements - I agree with him on that.
The fact that many (most) bolt on keels do survive is not his point - he is saying that, for that particular purpose, encapsulated / integral is a better solution - it is not the only solution, just simply a better solution.
To disagree with him on that point, one would have to claim that bolted on keels and spade rudders were not just 'satisfactory in the majority of cases' - but were actually a better engineering solution. Personally, I do not think that they are a superior solution, and I've yet go see anyone on this thread demonstrate why they are.

My point is simply that:

1. I have not seen the data to support his keel/skeg contention. The anecdotal evidence works both ways.
2. I believe his sidestepping survivable watertight compartments given his bend on safety is frankly daft.

Hence I wouldn't look at buying one. Others are perfectly free to disagree.

Time will tell how this brand gets on - we'll have to wait and see

 

[dunedin]

Dick Beaumont made a very explicit point in the video - he specifically said that the purpose to which the vessel is to be put should first be defined in order that the best design to meet that purpose can sought.

Sales and marketing ploys, IOR, are valid points in themselves but they do miss his overall claim - namely that encapsulated / integral keels and skeg hung rudders are inherently stronger engineering structures than bolted keels and spade rudders - does anybody wish to claim that the opposite is true?

OK I will bite. In pure engineering terms, steel is undoubtedly stronger than GRP. Therefore designed correctly, a bolted on keel should be stronger than one attached only by GRP.
In the almost infinitesimally few cases where a large cruising boat has had a keel failure, it has generally been the GRP that failed, not the bolts - albeit on occasion bolts pulling through inadequate or collision damaged GRP hull structure.
So perhaps the Arcona, Salona, X-Yachts etc approach of keels bolted to a steel structure, which also braces the mast foot and shroud plates would be a better engineering solution.
Or perhaps, as Brent S would suggest, the strongest engineering solution would not be a GRP boat at all but a keel bolted to a steel yacht ……….

 

[siwhi]

I believe his sidestepping survivable watertight compartments given his bend on safety is frankly daft.

I don't recall any discussion of watertight bulkheads. I may have overlooked it. Was that in the discussion, and do you know roughly when? Do you have any other detail on that aspect of the design?

 

[Chae_73]

Therefore designed correctly, a bolted on keel should be stronger than one attached only by GRP.

Not really, when the metal keel is bolted to a GRP hull as it's the strength of the GRP that is likely to become the weakest link.

It's the combination of the shape of the hull, the shape of the keel, the moment of force exerted by the keel through its attachment to the hull and the stress raisers resulting. Basically what @Laminar Flow said upthread.

Agree with the matrix type solutions as per x-yachts etc as having merit. I also agree that for 99.9% of boats and sailors, none of this will ever matter provided your boat is well made (correctly made unlike the unfortunate Oyster) and you don't go ramming it into terra firma on a regular basis.

 

[dom]

I don't recall any discussion of watertight bulkheads. I may have overlooked it. Was that in the discussion, and do you know roughly when? Do you have any other detail on that aspect of the design?

Apologies, I wasn't clear. My point is that there was no mention at all of this most important aspect of boat safety. All the Kracken has is crash forward bulkheads and a rear one, as many many modern yachts do. It's better than nothing but only creates survivable space in limited circumstances. Which is why many offshore racing and cruising yachts specify these bulkheads.

So the designer has accepted all the limitations of skegs and encapsulated keels, without even addressing the safety uplift of the survivable space afforded by watertight bulkheads.

That video -- to me -- depicted a firm more driven by obsession than reality. Hence, with an investor had on, I'd be very nervous indeed about that.

But of course, each to their own and time will tell!

 

[Laminar Flow]

And let's not forget, the only catastrophic keel failure in a large pure cruising yacht that I am aware of (the Oyster) it was not a bolt on keel that failed - it was the GRP keel and hull structure that failed.

That would be the pretty obvious point of failure, I would have thought, at the transition between materials with widely different properties.
In practically all impact damage from groundings it is the GRP structure that takes the brunt of it and is the reason Kraken uses a steel structure to absorb and disperse the loads.

A keel (attachment), regardless of shape, can absolutely be engineered to survive a grounding at hull speed and full load, as they indeed should. The stress loads for such an event are calculable and therefore a solution can be engineered/designed and built. Consequently, if a keel or its accompanying structure fails, in this or any other "normal and foreseeable" event, it was either poorly designed or poorly built.

 

[dunedin]

That would be the pretty obvious point of failure, I would have thought, at the transition between materials with widely different properties.

Actually the Oyster one was well above the transition between materials - the GRP to keel joint was lower down and looked to be fully intact, albeit sadly no longer attached.

But on your other point, not sure how easy or indeed safe it would be to engineer a keel to survive any grounding impact - without very serious injuries to crew and the rest of the boat. Like a car, which is designed to deform to protect the occupants.
Hitting granite with a solid keel at even 2 knots is a huge deceleration -throwing crew off their feet (ask me how I know !). Hitting granite at 10 knots, which most decent sized cruising boats can do, results in the crew being flung everywhere inside and outside the boat - and generally interior structures getting busted, as well as underwater stuff. Just watch a few of the Tjorn Runt videos, of boats hitting Swedish rocks with spinnakers up to get a sense of it.
Some Swedish boats have crash / crumple zones on their keels, like old Volvos, to try to reduce the damage in slow impacts. But these need repair afterwards, just cheaper repair.

But any serious rock impacts will usually need to be a lift and repair, which is fair enough. (Very different in the gentle transition between muddy water and watery mud in some softer, literally, locations.)

 

[siwhi]

Apologies, I wasn't clear. My point is that there was no mention at all of this most important aspect of boat safety. All the Kracken has is crash forward bulkheads and a rear one, as many many modern yachts do. It's better than nothing but only creates survivable space in limited circumstances. Which is why many offshore racing and cruising yachts specify these bulkheads.

So the designer has accepted all the limitations of skegs and encapsulated keels, without even addressing the safety uplift of the survivable space afforded by watertight bulkheads.

That video -- to me -- depicted a firm more driven by obsession than reality. Hence, with an investor had on, I'd be very nervous indeed about that.

But of course, each to their own and time will tell!

Thanks for the clarification.

So it doesn't seem much different in this regard (vis a vis bulkheads) to say Oyster, Discovery, HR, Contest, X Yachts, etc. I may be wrong in that respect, maybe they are significantly different. Even so, I can't ever remember being in a boat (and fortunately I've been in quite a few bluewater cruisers) where I've thought, yeah, it would be fine if I was trapped in this cabin 400 miles off Senegal with the wife and kids while the rest of the boat flooded, we'd do a Tony Bullimore for a few days and swim out when it calmed down. But there have been times when I've thought crap, I hope we don't drag onto that reef at 3am like they did, or sh*t that uncharted bommie was damn close, we'd have hit it at 8 knots and it would be instant game over.

I guess it depends on the buyers risk assessment regarding intended use. An X Yachts, Boreal or Garcia, or Skip Novak's Pelagic, or a nuclear powered ice-breaker can all go somewhere on a sliding scale in terms of their approach to risk management. To my mind the Kraken, with a GRP hull, would work well in both challenging temperate (eg rounding the Cape of Good Hope into a stiff breeze) and tropical climes (uncharted bommies in atolls), the staple of many a bluewater cruisers. If Greenland was at the heart of your cruising plans it would probably come further down the list. So I don't find much inconsistency in the design philosophy.

I found the discussion genuinely interesting and many of the points resonated with me. Some basic principles and philosophies, and clear risk and needs assessments come before discussing the pros and cons of a particular boat. The keel type is hardly new. I detect some curious malevolence to your observations.

 

[dom]

……I detect some curious malevolence to your observations.

Agree with basically all you say up until this last sentenc….

….I’m curious.

 

[Laminar Flow]

Yes, I have seen the Runt videos.

As you have correctly pointed out, the energy that has to be absorbed stands in direct relationship to the rate of deceleration upon hitting the obstruction.
The calculations I refer to are based on a deceleration from 8kts (example, hull speed) to zero in 0.25 sec with a strike near or at the forward tip of the keel. For all intents and purposes that is as near a dead stop as it gets, considering the potential deformation of a lead keel, the elasticity of the structure and the fact that the water, via the buoyancy, will absorb a deal of the rotation imparted by the hit.
The corresponding impact for a 40' boat of 8.17t is about 13.5t, with a total resulting force acting on the hull of 20t. Once you have determined the loads you can decide on the bolt/GRP strength needed at the forward end and equally the upward impact loads that need to be absorbed by the floors and structure at the aft end.

Interestingly, much is made on this forum about the supposedly superior engineering of modern sailing craft, yet it seems to be perfectly acceptable to go along with what must be seen as poor engineering and building practice for a vital part of the boat and that, without the shade of a doubt, could be improved upon. A modest impact and within the performance envelope of the boat that knocks all the floors in way of the keel area loose, is simply indicative of shoddy practice.

 

[siwhi]

Kracken's failure to spec these, in my opinion, reveals its entire premise as frankly ridiculous. Worse, it forces the design down a route where sailing ability will be seriously compromised, which is why I for one wouldn't buy one.

Personally, I doubt the brand will last.

Hence I wouldn't look at buying one. Others are perfectly free to disagree.

Time will tell how this brand gets on - we'll have to wait and see

That video -- to me -- depicted a firm more driven by obsession than reality.

OK, maybe I'm misreading your words, but you don't exactly sound like you wish them the best for the future. I'm not a fanboy type (though yes I welcome a diverse choice), but I think they have a place in the market. As I suggested I come at it from a first principles perspective and find I agree with much of the philosophy.

 

[Baggywrinkle]

This was done to death in Nov last year ...

Keel/Rudder design

... the forum might be getting a bit senile ? ? ?

 

[dom]

OK, maybe I'm misreading your words, but you don't exactly sound like you wish them the best for the future. I'm not a fanboy type (though yes I welcome a diverse choice), but I think they have a place in the market. As I suggested I come at it from a first principles perspective and find I agree with much of the philosophy.

Okay, perhaps I’m not being clear - again ! But fair point.

Every business is an expression of something personal and potentially something wonderful.

I think this one is poorly thought out with potential survivability implications. And I think that’s a valid question for prospective owners to consider. I would

 

[Laminar Flow]

This was done to death in Nov last year ...

Keel/Rudder design

... the forum might be getting a bit senile ? ? ?

Sorry, that thread wasn't by any stretch a technical discussion on the merits of different keel rudder configurations, but a rather disturbing psychological crossection of the various forms of "nautical angst" with a good deal of personal insult thrown in for good measure.

 

[Sandy]

This was done to death in Nov last year ...

Keel/Rudder design

... the forum might be getting a bit senile ? ? ?

Or the search facility on the forum total pants.