Grounding

[sailaboutvic]

being back on land for a while and With time on my hand , it been interesting reading what been written over the last two year regarding grounding,
it seems the advise given by some is to have your keel surveyed after a grounding to insure it's not going to fall off.

Does this mean boat are more liable to lose their keels now then they was twenty years ago?

It use to be quite common to sit against scrubbing post or an harbour wall to give a bottom a clean, change the odd sea cock or even antifound the bottom .

I first to admin, back in the days, it's not the first time we went aground tacking up and down the Orwell,
leaving it that bit to late to tack and ended up on the mud or sunking into the mud at pin mill while using a mooring buoy for the night.
Even getting caught out on the Dedham bar,
And other then a look into the bilge to make sure all was well we just carried on sailing just like so many have done before us.

I can understand the need to having your boat checked out after hitting an object at few kts , but really do we all now need go to the expense of an haulout and a surveyor every time we have a small miss hap.

When would you concern having a survey after a grounding?

 

[RupertW]

We grounded 3 times in the Med last year and I haven't given it a second thought as we were going slowly and each time went into gently sloping mud or soft sand. I do know the keel is still there.

 

[Sandy]

Things have changed greatly over the last 20 years. Hulls have got thinner, due to improved construction techniques, thus more likely to tear so worth checking.

There is a huge difference between hitting something at 5-7 knots and tying up against a harbour wall and drying out. One is a horizontal force and the other a vertical one.

 

[lpdsn]

The difference is Cheeki Rafiki. The cause of the loss of her keel was believed to be weakening of the bond between the grid and hull. There was no identified heavy grounding that caused this, so it had to be assumed that it had occurred as a result of a series of light groundings.

It is damage that an amateur would find extremely difficult to spot and a professional would quite likely miss it too, unless the keel was removed first. (The keel bolts clamp the grid to the hull making it appear it is still attached.)

The construction method is not a recent development but it appears that Cheeki rafiki was a particularly heavily used (perhaps even abused) example.

So it is really dependent upon the construction method of your boat.

 

[Tranona]

You have to keep a sense of proportion. Grounding covers a whole range of possibilities and it is up to the skipper to make a judgement as to whether there is potentially any damage following contact between the keel (and rudder) and the bottom. Speed, nature of the bit of bottom hit, design of keels and rudders, angle of attack etc all have an influence over the consequences.

An owner is perhaps more likely to not hit bottom in the first place or if (s)he does more likely to have a feeling about any potential damage. On the other hand a busy racing crew cutting corners might be more likely to dismiss it as just one of those things that happen, carry on and not bother investigating further.

So, the answer to Vic's question is that nothing has really changed. The bottom is still there, varying from soft and gentle to hard and unforgiving; there is still the possibility you may hit it if you venture into shallow water or areas with below surface rocky outcrops; the onus is on the skipper to try to avoid hitting things, but if it happens the onus is then on same skipper, knowing his boat and the nature of the "hit" to assess the potential damage and take the necessary action.

No excuses accepted.

 

[NormanS]

I think a lot depends on the design of the keel. Older yachts tended to have long keels, usually with a good slope forward. With a keel like that, if you hit something, even rock, you tended to ride up on it and if stopped by grounding, it was more gentle.
Many modern yachts have fin keels, some with a very short and narrow attachment to the hull. On many of them, the leading edge is effectively vertical, so if you hit something, the boat wants to stop dead. That's when the damage is done.

 

[newtothis]

The difference is Cheeki Rafiki. The cause of the loss of her keel was believed to be weakening of the bond between the grid and hull. There was no identified heavy grounding that caused this, so it had to be assumed that it had occurred as a result of a series of light groundings.

I was on board when CR was taken on to Bramble Bank at quite a lick. Admittedly, it was able to motor off but it made a noticeable thud.

 

[Tranona]

I think a lot depends on the design of the keel. Older yachts tended to have long keels, usually with a good slope forward. With a keel like that, if you hit something, even rock, you tended to ride up on it and if stopped by grounding, it was more gentle.
Many modern yachts have fin keels, some with a very short and narrow attachment to the hull. On many of them, the leading edge is effectively vertical, so if you hit something, the boat wants to stop dead. That's when the damage is done.

That illustrates exactly the point I am making. Owners of boats with different types of keel should operate their boats in the knowledge of the potential effects of grounding. So owners with boats where keels are more vulnerable should avoid situations that might lead to hitting the bottom. As post#7 shows, not all do this! Bit rich to whack something so well marked and hard and expect to get away with no damage.

So, with my old long keel boat with just 1m draft I would venture just about anywhere in Poole harbour in the knowledge that if I did stray out of the channel I just get stuck in the mud for a while. Now with 1.5m and a fin (of the more robust type) I am more careful and accept the limitations.

 

[lpdsn]

I was on board when CR was taken on to Bramble Bank at quite a lick. Admittedly, it was able to motor off but it made a noticeable thud.

That's very interesting. Have you been able to compare your experiences with what's in the MAIB report?

 

[PaulJ]

A stress that could easily be overlooked in the event of a sudden grounding is the stress on the backstay when you just stop dead...... I once hit an uncharted rock. It was quite traumatic, a big bang and we got thrown forward as we stopped dead from about 4Kts. Damarri is a very strong steel boat with a long keel (see my avatar), the sides of the keel are 6mm, the sloping front is 12mm and the keel plate is 75mm so I was fairly confident that any damage to the keel wouldn't sink us and on later inspection the only damage was a few scratches in the epoxy coating! However in the second or two as it was happening, my main concern was for the rig coming down. The whole boat rocked forward and the strain on the rig must have been horrendous as it shook and shuddered. Fortunately there are twin backstays so the strain on each was halved but I am convinced that a lighter, more conventional rig would have come down......... So if you are unlucky enough to have it happen to you, do get the rig checked too!

 

[rotrax]

Met a Belgian couple on a sailing sabatical in the early 90's in Cabo Bopina, near Marbella. They had a very strong home built steel 40 footer, and, as you did, hit a rock at sailing speed.

It put a 2 foot vertical crack in the mast, just below the spreaders.

I helped them rivet a SS plate over the crack, after drilling each end of the crack to perhaps stop it spreading.

The helm, the guys wife, broke a couple of ribs against the wheel as they hit.

I was not a sailor then, but was on holiday with the family. I assisted because their was no local help available and the owner/builder did not know how to repair the mast.

We found a S/S trolley discarded in a Yacht Clubs skip and made the plate from the top, panelbeating it to shape around the mast. We pulled it into place with rope-Spanish windlass style, drilled the holes and riveted it with alloy rivets-5mm ones. They were to be changed for monel later. The plate was bedded on some sika type stuff he had on board.

It seemed to work-when tightening the backstay no movement around the mast/plate/rivets could be felt by hand. They sailed off one morning, never to be seen again.

They treated the family to lunch at the beach resturant-that was nice.

 

[Sybarite]

In a recent thread somebody referred to Webb Chiles who had done two circumnavigations in a She 36 which he had bought from a forum member.

He recounted that he was sailing nicely along in light conditions - one foot waves - when the bow dipped into the water and just went down. All he could do was step off the deck into the water.

He swam for 26 hours and was carried 85nm by the current from where the boat sank - just off Fort Lauderdale.

He had previously had a glancing collision with a ship but apparently there had been no structural damage.

He surmised that the bottom just fell out of the boat.

 

[Joker]

Some years ago, my boat suffered from severe delamination [foam sandwich construction]. The builders claimed it was my fault, since I'd gone aground and had to be towed off a sandbank.

 

[lpdsn]

The builders claimed it was my fault, since I'd gone aground and had to be towed off a sandbank.

Had you?

By the way, was that the Polish-built cruiser?

 

[Joker]

Yes, I had, and it was.

 

[lpdsn]

Yes, I had, and it was.

I hope you eventually either got it repaired or got another boat that you're happy with.

I've also heard similar stories about a Polish-built Corby that had very serious de-lamination. It ended up being sold cheaply to a new owner who was going to build a brand new hull and transfer all the gear. Sounds like there may have been a generic issue at some builder or other. Not sure if they were built at the same yard.

Not heard any stories about it suffering a grounding.

 

[Joker]

I got it repaired - at my own expense.

I think it was a 'one off' - someone took a shortcut. And it it wasn't mass production. From what I can gather, they were all built in a large shed somewhere.