A fellow Dane experienced a hard encounter with a rock in his H370 from 2006/2007.

I adviced him to get a professional to check the keel since it looked quite serious to me.

The boatyard and the insurance company told him that it was merely a cosmetic issue, and I suppose the damage has been repaired with some putty/mastic of a kind. The keel has not been dismounted, and to my knowledge, the nuts on the keel bolts have not been checked by first removing and then remounting them to see if the bolts still were solidly fastened in the keel.

I am not an engineer, but as I see the damage, there is a risk that either the bolts are stretched, and thereby weakened, or alternatively the thread may be deformed and weakened. Since  the damage has been in salt water for some time, the water have seeped into the keel to induce further havoc over time.

Is there a myhanse-member with knowledge about this?

A reason for the insurance company to downplay the damage could be the price of dismounting the old keel for repair, or even the price of a new keel. Check boatoon.de for prices.

:Kjeld

This compound ( also on my keel ) has also flattend the aurface on the side off the keel.

I think it is cosmatic, and you will see it if you remove the compund on the sides off the keel at that place.

The hanse is a very strong boat but beside that wenn you hit the rocks it will flex and then the compound on the side off the keel hul joint will come off.

I would like to see the result wenn the compound is taken off on this damages.

Gr Marcel

If you do not feel it give away it should be ok.

Stainless steel keel bolts when exposed to sea water in a anerobic envionment suffer corossion.

That is typical of a keel which has been moved and allowed sea water access to form a well of sea water low in oxygen.

Any responsible surveyor should advise insurance company that  only remedy for this keel is removal, inspection, and re-sealing this damaged keel with approved sealant.

Have a look at the evidence

http://coxeng.co.uk/metallurgy/crevice-corrosion/" rel="nofollow - http://coxeng.co.uk/metallurgy/crevice-corrosion/

Im not a surveyor,  but I designed equipment for North Sea Oil, and saw instances of structural failures due crevice corrosion.

I'm married to a Material Scientist. She charges too much to ask her analysis?

A friend was having increasingly serious water ingress on his boat last year and asked me for help; it was plainly though the keel bolt areas.  Turned out he too had bounced off a rock two years before and like your friend had been told at the time it was 'cosmetic'. Going with him to a dockyard that's professional enough for Navy contracts he was told that at the very least the bolts should have been withdrawn for testing and that they very strongly recommended that the keel be dropped, checked and re-attached.  The cost - a staggering £11000 for his 37 footer, although this included making good the unseen damage to the keel fixtures and attachment points.  It was pointed out that the keel would have been flexing more and more throughout the previous 2 seasons increasing the damage so timely in-depth checks are essential in such cases.  They'd seen a number of grounding-damaged keels and their only surprise was that more keels don't fail dramatically.  While such failures thankfully remain rare, the yard (after taking his money!) wondered how many are just 'hanging on' out there hidden behind putty and other gloop.    

There's no way I would go to sea in a boat with such obviously serious damage without either dropping the keel or at the least having it radiographed if feasible given the areas involved.   It may be that the yard and Insurance Company are indeed correct and my opinion is well OTT but they are literally asking your friend to bet his life on it.  It would be interesting to see if their position would change if they were warned - in writing - of their liability in law should they be wrong.  There again, your friend is still betting his life - not much satisfaction if all goes wrong! Having lived 7 fantastic years in Norway I'm well aware that prices tend to be higher in Scandinavia - but I don't think you guys value your lives any the lesser!

MVH

Iain

 

Ratbasher and Perry have made some points, which reflects my own worries about the damage.

The incident happened in the summer of 2019 in the Swedish skärgård, and the owner asked me for an advice when he discovered the damage in april 2020. I adviced to let a professional evaluate it. The shipyard and the insurance company opted for a repair. Two weeks ago, I found the old keel-drawing on my PC and sent it to the owner. He was of the opinion, that the keel bolts were penetrating the depht of the keel, and seeing that this is not the case, he again asked if I thought that there was reason for concern. I never had much confidence in the repair, so therefore I asked for other opinions in this forum. (If it was my boat, I would be worried when sailing).

There has been no water inside the boat and no visible cracks.

My concerns are:

Metal fatigue due to pendulum movement of the keel during 8 months.

Salt water inside the keel, and possibly around the bolts.

Possible stretching of the keel bolts and thereby weakening in the metal.

I do not know if the insurance guy or the shipyard are aware of the design of the keel.

Some years ago, a danish blue-water sailor (S/Y Petra) lost the keel en route to the Azores, so it can happen. It was a Bavaria with smaller keel bolts than those of the Hanse 370, but anyway.

I have asked the owner for more photos, and a fuller description of the damage and the repair that was made. I have not seen the actual damage, just photos.

To Marcel: I admit, that the connection seems to be covered with compound. This is not the case with my 400, here is just 2-3 mm of glue between the GFK bottom and the keel, and no compound is hiding the connection. I suppose, that the 370 has the same low distance between GFK and cast iron.

 are you and your friend shure the damage on the bottom and the crack on top of the keel are from the same(date) grounding case ?

looking at the pictures ( We can only relay on those ) it seems to me the damage on the bottom is

1) from a more recently date than the crack on the connection keel and the hull.

2) the damage on the bottom part (Lead?) is IMO not from that size that this will result in the crack on the top (Cast iron) of the keel.

We have the same cast-iron and lead keel and the lead part is working as a absober and to me the damage on the lead part looks like a sideway impact and not as a frontal one on a rock .

a few years ago we had a small frontal grounding on a rock near Mykonos and the damage on the lead was much significant than in this case and there was not even a small crack on the hull-keel connection our the connection upper-lower part of the keel .

Our is done the same way Marcel explain in his reply, a compound between hull and keel to make this connection more smooth and a small  epoxy fill( I was there when they put the 2 parts together) between lower and upper part of the keel.

See also my thread "Bad keel material".

The lead Hanse used is recup material and not clean from dirt and other sh*t.

We have many spots on the lead part where the dirt is breaking out.

Take attention to this.

The Picture with the lower part of the keel shows Hempel Epoxy Filler which is the most common filler in Denmark for DIY boat works. It is very expensive and RepairYards would probably use a cheaper bulk product.

Hempels Epoxy filler is a good product, but here I think it indicates that it is a DIY job or from a small Yard/Boat Shop?

Hempel Stock Photo of Epoxy filler - When mixed it has the exact same color as Cook's Friends picture:

The lead is a different story to me. That is more a shape or a cosmetic thing which you can repair or not. The issue is that the whole lead part is not really protected. normally we should all cover our keels with GRP completely but who is willing to do all the work. Than you have solved the rust issue as well if you are connection the hull and the keel with laminate. 

In the meantime we all fight against small rust spots and the very small crack rust between the lead and the iron but that is really different from the picture from the beginning. 

So take of the keel - better safe than sorry!

The max torque values depend on the strenght of the bolts, but you will need industrial tools to work with those large bolts. The normal DIY tools are too tiny.

My own torque wrench can manage up to 210 Nm.

This indicates, that to the 30 and 42 mm bolts you need large industrial tools.

It may also be wise to unfasten the bolts one at a time, and only when the keel is on a hard surface.

http://www.chapmanssfs.com/torque-tightening-values-structural-steel-bolts/" rel="nofollow - http://www.chapmanssfs.com/torque-tightening-values-structural-steel-bolts/

The steel grade is normally stamped on the end of the nut (8.8 - 10.9 - 12.9).

A M30 in grade 12.9 has a value of 1977 Nm / 1458 ft-lb.

My danish sailor friend has decided to trust the boatyard in the evaluation, that the keel is repaired to a state, where it is as good as new.

He has a report, which tells, that the insurance company will cover any damage happening in the future, which can be blamed on the old mending of the keel.

He even tells me (joking I hope?), that as a kid he sailed with retractable keel, so he expects to be able to reach a port in case his keel falls off.

:Kjeld