What they don't tell you about production boats

[geem]

Not my title but the title of the video. Worth a look at a Hanse following a grounding and the subsequent repair

 

[Fimacca]

Good vid.
Building down to a price. Mass production.
All works well if you are lucky, and there are no impacts !

Was it whilst on charter with other parties that the accident happened?

 

[Daydream believer]

I hit a rock at slightly over 6kts whilst motoring in my Hanse. 311. I was thrown forward as the boat stopped dead. When lifted out of the water the insurance surveyor could find absolutely no damage whatsoever. So Hanse yachts are quite strong in the keel area.
But it has to be said that if one is going to treat the boat like a dodgem car one is going to have to expect damage.
If one wants to see a series on the repair of a yacht that had keel damage then the one by Expedition Evans is worth a look. The work to repair the Beneteau is really extensive.

 

[pvb]

I hit a rock at slightly over 6kts whilst motoring in my Hanse. 311. I was thrown forward as the boat stopped dead. When lifted out of the water the insurance surveyor could find absolutely no damage whatsoever. So Hanse yachts are quite strong in the keel area.
But it has to be said that if one is going to treat the boat like a dodgem car one is going to have to expect damage.

Quite right. A hard grounding will inflict damage, and boats aren't designed for that. Getting run into amidships will inflict damage, and boats aren't designed for that either. Cars are designed for impact damage, but often the cost of repairing that damage is more than the car's worth. So boats are really no different, as impact damage repairs are big money.

 

[Deleted member 36384]

Interesting to see how the grid is built and bonded to the hull and good on the bloke for his show and tell.

 

[pvb]

Interesting to see how the grid is built and bonded to the hull and good on the bloke for his show and tell.

There's mention in the video of Hallberg-Rassy, with the implication that their boats are more expensive because they're built better. However, the Hallberg-Rassy website mentions their inner grid being "bonded" to the hull, and includes this photo which doesn't show a lot of lamination in evidence...

 

[ip485]

It is an interesting discussion and does highlight the extent to which "liberties" are taken in areas that cant be seen. Arguably some real cost cutting and a reasonable explanation of how the boats can be built so cheaply. On the other hand, it does occur to me that with a far stronger construction while it might well ride out more minor collisions, the costs to rectify more major collisions could be far greater because there are effectively no crumple zones. My own IP is incredibly strong and of course the whole keel is part of the structure. It would take a substantial collision to cause a problem, but the energy must go somewhere and there must be a point that severe structural damage will result. Rectifying this amount of damage could be far more work, than rectifying the relatively flimsy construction of a Bavaria.

 

[Rappey]

This is the 3rd video I've seen in the past month regarding a grid becoming detached and it's not something I've been looking for.
I now wonder with the keel putting a port and starboard force on the matrix while the boat is rocking what is the long term effect regarding fatigue on the bonding ?
Maybe a matrix unbonding will become the new keel falling off

 

[wully1]

“How thick the hull is “ 10 mil......

“Glued together with brittle putty..”

Nah....

 

[Daydream believer]

“How thick the hull is “ 10 mil......

“Glued together with brittle putty..”

Nah....

So why does the hull need to be thicker than 10 mm. My last timber boat had a hull that was 9mm planking. It was rotten in places, such that when i had the paint shot blasted off, it blew holes in the hull. Prior to that it leaked like a sieve. Can you tell me which is better.

 

[Elessar]

When I had a boat business we blasted a rassey that was on its first owner. He hadn’t specified a bow thruster.
A base thruster tube had been fitted unknown to him, and poorly blocked off and anti fouled over. The tube was full of water.
Gel coat on rasseys is also far more inconsistent than the mass boat builders. Lots of pinholes appear due to bubbles under the surface.
Rasseys sure have a perception of quality and some lovely wood. But it is, in my opinion, just perception.

 

[Zing]

Plexus. Ew!

 

[Laminar Flow]

There is absolutely no doubt that the shorter the keel root and the higher the aspect ratio, the greater the loads are during a grounding and the more the risk of catastrophic damage.

The whole point of a grid to absorb the keel and rig forces becomes rather pointless when it cannot receive and absorb the loads of an accidental grounding because it is not properly attached to the hull. As the owner pointed out, it resulted in a crack running down the centre of the hull and could have just as well ended up with the rear keel root penetrating the 10 mm hull skin.

The use of a thickened, non reinforced resin slurry to "bond" the grid to a hull strikes me as a poor engineering solution. Many boat building techniques fillets are used for optimal load transference; they are always glassed over with multiple layers of glass.
For years now, deck/hull joints have been successfully glued with something like 3M 5000 and without the use of fasteners. Perhaps this would be a better method of attachment for a grid.

The Baltic, which appears to be the owner's preferred cruising ground; is littered with thousands of unmarked rocks courtesy of the ice age glaciers. Perhaps he needs a more robust vessel for local cruising.

 

[Laminar Flow]

Quite right. A hard grounding will inflict damage, and boats aren't designed for that. Getting run into amidships will inflict damage, and boats aren't designed for that either. Cars are designed for impact damage, but often the cost of repairing that damage is more than the car's worth. So boats are really no different, as impact damage repairs are big money.

Cars are designed to absorb impact damage to protect the passengers, not to improve repair-ability.
Boats should be able to survive a grounding at hull speed, so as not to drown it's crew. Considering that grounding is a relatively common occurrence while cruising, I would expect a boat to come out of that at better than a write-off, or a two year refurbishment.

 

[Daydream believer]

The whole point of a grid to absorb the keel and rig forces becomes rather pointless when it cannot receive and absorb the loads of an accidental grounding because it is not properly attached to the hull. As the owner pointed out, it resulted in a crack running down the centre of the hull and could have just as well ended up with the rear keel root penetrating the 10 mm hull skin.

On the other hand the 10mm skin probably flexed thus partly absorbing the shock, rather than a 12mm skin that may have shattered & been holed.
One has to take account of other factors. Weight being one of them. A bit pointless building a boat, of which 1 in 30,000 owners decide to run them into a rock at warp speed, such that it rips the keel off; thus spoiling performance & increasing cost exponentially for all. Especially when, having gone to that effort, an owner will then find another way to wreck his pride & joy

 

[Deleted member 36384]

Cars are designed to absorb impact damage to protect the passengers, not to improve repair-ability.
Boats should be able to survive a grounding at hull speed, so as not to drown it's crew. Considering that grounding is a relatively common occurrence while cruising, I would expect a boat to come out of that at better than a write-off, or a two year refurbishment.

The boat did survive a significant grounding without killing it's crew as do others of this design that ground. Indeed many older designs that I am aware of that had significant groundings not only saved their crew lives but also ended up with significant repairs: Sigma 41, grounding at Kyles of Bute, Contessa 44 grounding on Inchmarnock west of Bute, Golden Apple, cold moulded design grounded at Toward Point, Sigma 362 grounded at Ghia, an X design (can't remember type) grounded on the east coast of Great Cumbrae. Recent fatalities in sailing associated with similar modern designs appear to be either poor repairs or incorrectly manufactured to the designers requirements.

I dont think the point you make stands up to scrutiny. It's fair to not like modern designs but it is not fair to criticise the design based on flawed assumptions. The designers make boats that not only meet an agreed design standard but are safe to sail and are in demand.

 

[matt1]

How surprising that this would turn into a thread about modern Vs old or fin vs long keel again

I had held off answering this post as I’ll declare an interest from the outset; having the same model as the original vlogger. I’ve been hugely impressed by the build quality of Hanse’s having got under the skin of her whilst running all sorts of wires in for accessories so I’ve had the sole boards up and been in every nook and cranny of my boat, and can affirm that bulkheads are very thick, substantially laminated to the hull (as are other webs and half bulkhead). This is my fourth boat (others were solid, well founded British brands) and I’ve been very impressed by the engineering on the Hanse.

Back to the original vlogger’s woes; this is in fact the second time this chap’s boat has ended up in contact with rocks. In the previous season it ended up on the rocks in the hands of some charterers, damaging the rudder, bottom of keel and the stem. We don’t know if there was unseen / undetected damage from the first incident; hairline cracks etc which may have contributed to more damage than expected with the second impact. (Damage inspection and routine checks seem increasingly important as evidenced by the ORC including them in offshore racing now)

Ther other point to bear in mind is that Hanse’s are relatively heavy boats (9,800kg Vs 7,900Kg equivalent sized french model). I’ve always appreciated displacement in a boat (given enough sail area!). Loaded and with full tanks my boat is probably around 12 tons. She typically cruisers at between 6-8kn. Just think of the energy of a cast iron keel hitting an immovable granite surface at 7 knots with 12 tons above it! I think most boats would need some degree of repairing after that.
It’s unrealistic imho to expect otherwise.

I know everyone “bigs up” their own boat on here but I can genuinely say I’ve sailed upwards of 50 boats, including a Beneteau across the Atlantic and the Hanse is the boat that has inspired more confidence offshore than any of the others. Much of that is her incredible balance and handling but also her construction. I’d have no hesitation in taking her anywhere and I’m confident she would cope with anything I could throw at her.

I hope the original vlogger gets his repairs finished and can find a way to avoid having to charter his boat out. What’s that expression “nothing handles like a hire car”

 

[wully1]

So why does the hull need to be thicker than 10 mm. My last timber boat had a hull that was 9mm planking. It was rotten in places, such that when i had the paint shot blasted off, it blew holes in the hull. Prior to that it leaked like a sieve. Can you tell me which is better.

Now who said the hull had to be thicker than 10 mm my dear little Mountain clone?

 

[pvb]

Rectifying this amount of damage could be far more work, than rectifying the relatively flimsy construction of a Bavaria.

How did you form the opinion that a Bavaria is "flimsy"? They're quite heavily built.

 

[davethedog]

Love the production boat bashing that is about, so what about the big Oyster that was severely damaged? Just saying....