About those keels...

[andy_wilson]

I tend to share this view...

"In my opinion any yacht keel should be so strongly attatched to the yacht that it is the last thing to come off.

"If the rest of the hull is smashed into matchwood or ground up into tiny bits of GRP the keel should still be attatched to the last bit left."

I also like the idea of the Scandanavian boats, that are likely to hit something hard in the Baltic, and can take it.

My question is; Is a boat with a sacrificial keel fit for it's purpose, especially when by sacrifice, we mean the entire yacht?

I would suggest that fit for the purpose should allow a yacht propelled at up to hull speed, under sail or motor, when hitting something solid like a rock, wreck or container f'rinstance, may perhaps sustain damage that needs repairing, but not to lose the keel completely, or lose the yacht completely.

Part 2 of the Consumer Protection Act 1987 (as amended by the General Product Safety Regulations 1994) imposes a duty on all producers and distributors of goods to ensure that their products are safe. It is a criminal offence for a company (or it's directors) not to do so. On the basis that this is enshrined in EU directives in countries like Germany where some yachts are built, and in the UK where some are sold, aren't some manufacturers and distributors 'sailing a little close to the wind' on this one?

I confess an interest. I like to explore upstream a bit, and I will readily take a drying berth. I would be a fool to buy a boat that couldn't take a nudge into the mud without me having a panic attack, let alone sail straight over a shallow section of river dramatically slowing and physically lifting the boat as we pass.

I think all cruising yachts should be able to do that!

 

[npf1]

Someone once told me that in Sweden there is a regulation that stipulates yachts must be able to take hitting a rock at 6 knots. Don't know if it's fact or fiction but it does sounds rather sensible to me.

 

[john_morris_uk]

[ QUOTE ]
I would suggest that fit for the purpose should allow a yacht propelled at up to hull speed, under sail or motor, when hitting something solid like a rock, wreck or container f'rinstance

[/ QUOTE ] You lost it for me at this point. At 'up to hull speed' does not imply seamanlike behaviour. I like exploring up creeks as well, but by your own admission, we both slow down.

A car has a bumper, but there's a difference between preventing damage at parking speeds, and preventing damage at normal driving speeds.

A yacht is designed to stay afloat at sea in the category of weather and waves that it is built to (under the EU rules). I might not like some German built yachts, and I might not ever buy one, but to say that yachts have to be able to hit things at full speed without sustaining huge damage is what 'Yes Minister' would have said was a 'brave statement'.

 

[AlienP2]

Your comment about nudging the mud is a very valid point.

If the keel falls off at 5 kts when hitting a rock, what happens at 2 knots when hitting mud or a gravel bank? What happens at half a knot but repeated 20 or 30 times?

What happens if you drop off a wave or are beating into a steep sea, well heeled over? All these things exert significant forces on the keel / hull joint hundreds of times a day.

As a structural engineer I am naturally very concerned by anything that fails catastrophically under what must in all honest be considered a service load.

With regards the view that there are hundreds of these boats out there so statistically a measurable number must be defective doesn't add up. How come its these ones that are hitting the rocks? I think we are talking about more than a few being at fault.

 

[Sans Bateau]

But shurely it not unreasonable to expect that if a yacht hits a partly submerged solid object at hull spead, that its keel should stay in place?

 

[Vagabond]

The Keel should stay on full stop.

Bit different if you have a racing yacht though and you should know that you have a lightweight machine after all you don't get airbags in an F1 car.

 

[andy_wilson]

seamanlike behaviour

Rock or (marked) wreck OK, not seamanlike but it happens - a lot, just like bouncing across the (sand)bar in a bit of a swell. That's why I included submerged container, which by it's nature has a bit more give.

I didn't exactly say (or mean to say) yachts have to be able to hit things at full speed without sustaining huge damage, but my thrust was certainly that they shouldn't be sinking, but may need repairs.

I'm interested in other peoples take on what a 'cruising' yacht skippered by occasionally fallible humans, should be built to withstand with no damage / some damage / heavy damage / keel torn off and sinks.

One big whack?

Occasional gentle bounces?

Drying alongside?

None of the above?

 

[capt_courageous]

You do not get air bags. What you do get is a superbly designed survival pod.

 

[Vagabond]

[ QUOTE ]
What you do get is a superbly designed survival pod.[ QUOTE ]


Very true!

Of a keel I would demand:

One big whack

Occasional gentle bounces ... bit hard to avoid really.

Drying alongside.

The yachts that hit the wreck off the needled on the RTI race kept on sailing I think so they did very well.

 

[john_morris_uk]

Re: seamanlike behaviour

Perhaps I was over reacting to the implication that I thought I had read.

I would be very unhappy if my boat couldn't:

1. Take the ground without groaning or altering shape too much.

2. Have its keel be able to hit things at a fairly gentle pace and only lose a bit of antifouling. (This is a bit contentious, but the forces on a yacht in a storm are huge, so my argument is that hitting something fairly solid at less than full pace out to be ok.

I do nudge to bottom from time to time. I don't even think about looking for damage... I expect the boat to be OK with the gentle slowing down that we experience sometimes as we wonder off the charted bits!

 

[sighmoon]

Re: seamanlike behaviour

I'm sure a better design job could be done within the price: perhaps all that is needed is a foot or so of GRP crumple zone down the leading edge of the keel.

 

[AlienP2]

Re: seamanlike behaviour

I don't think a container is that forgiving. It has corners for a start that tend to be near the surface. I would expect the keel to stay on, but wouldn't be surptised if the container took a gash out of the hull in a glancing blow. It then comes down to how the yacht performs when holed.

By the way - any more news on that yacht that lost its keel whilst racing off SA? Stingo posted a photo a couple of months ago. It was found with a very neat hole where the keel used to be.

 

[Spicemariner]

Re: seamanlike behaviour

Well I own a Bav, sailed her across the Atlantic, hit a floating railway sleeper at speed, she was knocked over in Hurricane Ivan but oddly the keel was still firmly attached. She was brought back to UK fixed up and new owner delighted with her. I bought another Bav just about to sail off again a bit further this time. Give it a rest guys.

 

[fireball]

Re: seamanlike behaviour

No one mentioned a Bav ....

 

[Mirelle]

Well, this is probably the wrong answer

My boat was built to be sailed out of a river (the Deben) which has a shingle bar at the entrance, and generally sailed around the southern North Sea, which has some quite thin bits (don't ask me how I know that... /forums/images/graemlins/wink.gif)

So, we have a lump of iron weighting three and a half tons, held on by ten inch and an eigth wrought iron bolts each of which passes through the teak keel and then the three quarter inch wrought iron floors. The iron keel runs the full length of the wood keel and extends to protect the heel of the rudder.

It is obviously designed to take an impact, and I should be very surprised indeed if it came off!

 

[jonathankent]

Re: seamanlike behaviour

[ QUOTE ]
No one mentioned a Bav ....

[/ QUOTE ]

but we all know that with the other recent post about a bav losing its keel and the mention of some german boatbuilders, we all know eactly what was being insinuated... don't we?

I quite agree that people should just leave the bavs alone...

 

[Mike21]

Re: seamanlike behaviour

Did some trawling on the net re Bavarias.
Seems with the exception of the match 42 which seems to be a bit of passing the buck between Bavaria and the charter co as to what really happened and who's at fault, most other links to keel problems on Bavarias seem to lead back to YBW forums.
Either I'm looking in the wrong place for info or most of the problems with keels seem to be either heresay or possible people being economical with the facts since I would expect if it was such a big problem as being suggested, it would be far more widely publicised

 

[mikejames]

Re: seamanlike behaviour

I think that there are several classes of problem here .

The boats from a certain manufacturer are 'new' when the keel falls off. Perhaps the laminate is not fully cured when the first impact happens owing to an efficient delivery pipeline.

I heard of one losing its keel on the Brambles on its maiden voyage some time before more serious problems began to appear.

OTOH I have also read a write up of a Westerly where the keel started falling off 15 years after build and it was found to be held on by gelcoat and thick mostly uncured laminate.

Boats with keels bolted onto flat bottom sections seem to have more trouble keeping them than those which have moulded stubs on the hull.

Some boat designers are more optimal with their designs than others. There were initial problems with a certain 24 foot sportsboat where they would lose their keels on a run and the designer insisted his initial calculations were correct and that adding about 50% to the diameter of the bolts on subsequent boats was only to stop customers worrying.

 

[jenku]

I doubt it's a regulation. After all, Bavarias are sold in Sweden as well. Still it's not a bad rule.

 

[Sailfree]

There are many charter companies in the Solent that have Bavarias. Have a look at them in the winter lift out and their keels show they have hit or scrapped the bottom many times but the keel is still intact.

Yes inevitably there must be a limit to the force of the impact but what limit would you specify.

It appears to me that may criticising are the ones that would never buy a Bavaria and would still not buy one costing 10% more due to heavier keel hull layup and connections.