Top Heavy Tupperware Dishes

[Merlyn]

See the 168,666 Anthem of The Seas just suffered a turn back embarrassment job, deep vee hulls versus Top Heavy Tupperware Dishes, wonder what the QE2 would have done in mid Atlantic encountering similar seas? Answer, reduce speed and keep steaming. Oh the proper ocean liner days eh? Deep V entry hulls, proper ships. Nowadays pack all the fare paying passengers into "seagoing" blocks of flats mounted on what looks to me like fuel tanks and then give them all their money back. Imagine coming up from down below to upto 4905 honkers just released from their cabins where they had been boxed up for some hours. Taxis around the Caribean jobbies.

[JK]

Imagine all the toilets to be unblocked.
A friend of mine was CE and Tech Super for NCL. He posted about hitting a storm on the Norway, she laid over 4* and they kept on at 20 knots. He made pretty well the same observation.
It always surprises me to see furnishings sliding about on the cruise ship videos. The videos I saw of the weather was about what we commonly see in the N Atlantic. It makes you wonder exactly what the stability of these ships is, even with stabilizers and probably tank stabilizers.

[Merlyn]

Maybe it will go into dry dock for " specialist modifications " ie bilge keels. What exciting new technology methinks. Dunno how to stitch bilge keels onto flat bottoms so maybe Mr Belzona may be used to glue on stabiliser extensions. Perhaps it will be transferred onto a lake in Switzerland as a floating hotel or similar. Or fitted with rapid flood up/ pump out tanks like a submarine or maybe flood it up and repaint the waterline six foot up to reduce its C G . Don't think I will be booking a trip on a honker jobby though.

[Big Pete]

It is not only the stability that is the problem, the underwater Hulls on modern Pax , ferry and Car Carriers are streamlined for efficient, relatively high speed. Immediately above the waterline the Hull flares out massively to increase cargo volume, the result is that in a head Sea they smash into the waves and incur structural damage forward.
On my own PSV, the accommodation has been moved right forward and extra Decks added to reduce the length of the accommodation and increase the length of the cargo Deck, compared to older ships. This means a great concentration of weight right forward, so there also has to be a lot of reserve buoyancy forward to stop the bows just diving into a wave and going straight down. In consequence despite massive power and a speed of over 12 knots in calm weather, in a head Sea she drops down to 4 knots and head butts every wave, making any sort of rest impossible, and risking structural damage.
Another clever touch on many modern PSVs is to move the Emergency Generator to the monkey Island, on top of the Bridge, where it is accessible by vertical steel ladders on the outside of the Bridge, so in the North Sea Winter it can only be accessed safely in Port. But, again, it increases the % of the ship's length where cargo is stowed. I can't understand why Flag States don't insist that the Emergency Generator is readily accessible, in all weather conditions. Maybe they never heard of Murphy's Law?
BP

[Merlyn]

Thinking about it further and looking at the robotic bars serving cocktails with no bar tenders in sight, full size bumper car tracks, Hyabbs 300 feet above the waterline with maybe several fat folk on board swinging about together with gravity free Perspex tubes floating passengers together with the blocks of flats effect it is perhaps small wonder that the CofG is so high up. However, spurred on by the navalarch together with Felixs writings and calculations I have thought of a solution and an alternative to the ship being sentenced to some far off landlocked lake somewhere or an oil rig accommodation ship so together with my old second/ firsts/Chiefs reference books and slide rule, ( no calculators in the early sixties ) I have worked out the total port and starboard surface areas and would consider that this does indeed present us with a very large sail capture area. However it would appear that the sail has no belly to it to retain the captured wind and reduce significantly the wind sheer effect. However if we look at the total outside balcony areas we can observe that the wind penetration affect more than offsets the windsheer factor. Indeed it would appear that it would, to some effect trap the wind into those areas and as such would " key in / lock in " the power of the wind the " fingers of the wind " effect being apparent here. Further more apon a bridge audible signal if all the relevant balcony doors were to open at the same time the wind shear effect could possibly be reduced even further. As the glass sliding doors represent approx 35 % of the total glassed in area the wind penetration would increase significantly by entering the cabins. I have seen pictures of ships, tankers and the likes fitted with huge masts and sails to " assist " the way of ships and here we have a virtual purpose built ship without the need for masts. However a further problem now presents itself, this ship appears to skid about in a bit of a blow antagonised no doubt by its very flat Tupperware dish type bottom. Several drop keels activated by maybe five stage hydraulic Rams could solve this problem, the old cable and winches system not perhaps being suitable on this design. These keels would reduce the heel of the ship in a blow and prevent the slide ways slip motion together with keeping it upright. As a bonus point the reputation of the builders/ designers/ owners might be, to some degree be salvaged and a face saving episode may be achieved. However there still exists one problem to render my super design modification possible? The only clue I can offer is to inform you that on this occasion the " one fifths rule " definitely does not apply in this case. Anyone?

[JK]

A modern take on a Flettner ship, Merlyn?

[Merlyn]

Just trying to save the ship, but what else do I need for my super saving the situation? What's missing? What's the 1/5 rule referral? Felix may have to come out of his retirement to help you on this one maybe. Get the current Lambs out?

[JK]

Evolution Strategy??

[Merlyn]

Think tiller flats

[Merlyn]

Tiller Flats= Steering gear = rudders? This ship has no rudders as its PP Propulsion. Therefore my suggestion of converting it to sail would not work without rudder additions. Although it was kept quiet and not reported straight away this ship suffered the complete loss of its Port Anzipod owing to all four skew gear motor clutches burnt out thus rendering it inoperative. It limped back to port on the Starboard engine only. Apparently they had to report this to US coastguard in order for the ship to be released for its next trip and it was only then that the loss of the Port Anzipod became known to Joe Public. Storm damage was blamed? So the turn back was weather/anzipod reasons.So maybe if you get a trip on the latest anzipod equipped ship you ought to take a set of clutch plate ferodo type inserts with you should you wish to make it back to port safely? Bet that was a stinky job changing them. And they did the other sides unit too. Wonder why the fail safe Spring default arrangement didn't work? As this model is the latest type and ABB boasts how trouble free it will be despite numerous water ingress problems etc etc in the past it would appear that there still is some way to go on this concept of trouble free seagoing propulsion . Could it be the seas were motorising and driving the clutches against the electric motors or maybe the freewheeling effect taking charge and the driver becoming the driven? As a further fail safe option perhaps a return to the old handraulic method of anchor raising several 15 foot bar extensions fitted into slots machined into the Anzipods slew gear hub and maybe six extensions with six bodies cranking it round manually in order to position the pod to steer the ship on the right course. What if both clutches burnt out in that storm? "Dead " in the water or what. Image the side slop effect with all that superstructure? Image trying to get towlines from giant sea going tugs onto it. Image trying to evacuate nearly six thousand people plus in those kind of seas. All those MW generated and no place for it to go propulsion wise.

[JK]

I completely forgot about the azipods and was thinking about rudders between thinking about fuel and coatings. Three totally unrelated topics was making my mind ache.

This is incredible. It is not unlike the QM2 and all the electrical issues she had when new. very hush hush.

[JK]

I went looking further. Nice picture included here.

http://www.maritime-executive.com/artic ... e-in-storm

[Big Pete]

My own ship has Rolls Royce Azipuls and may be slightly different to the ABB ones but we have had problems with the steering gear as well.

We have 2 steering motors driving through Torque limiting Safety clutches and a reduction gearbox onto an annular gear round each Azipul.

Each motor has an automatic electric brake on the free end, when the motor is energised so is the brake and it pulls off.
Also on the Free End is a "Digital Encoder" this has a bearing in the middle which fits over the motor shaft and a light bracket to secure it to the casing. Inside there is a laser which shines through fine lines cut into a mirrored disc, light receptors turn these into Digital Pulses. Counting pulses gives the angular displacement of the shaft, integrating with respect to time the velocity, integrating a second time gives acceleration and so on.
The feed back from these is used to control the power to the two Motors which are each driven by their own Variable Frequency Drive, but are obviously, mechanically synchronised through the gearing to the Azipul.

The first failure was the bearing on one of the encoders seized, the entire encoder started turning with the shaft and sheared off the securing bracket, then wrapped all the electrical wiring round the shaft and broke it. This triggered a feed back failure alarm, and the Chief on board at the time investigated, found the fault and completely electrically isolated that motor and carried on. When I came back from leave realised that, with the power isolated the brake on this motor was permanently engaged, so I jacked it off manually until spares arrived. The ship continued to work normally, management arguing that the ship had 2 Azipuls working and 3 steering motors so was still DP2.
When the new encoder was received we fitted it and everything worked normally.

Later we had a problem with one of the Safety Clutches on the other Azipul failing, again the ship continued in service for months, until the spares came and were fitted. After a few months the safety clutch failed again. When we fitted the new safety clutch we noticed that the currents drawn by the two motors were different and were unable to work out why, Rolls Royce suggested changing the encoders and that cured the problem, so it appeared that the encoders were giving faulty feed back signals, and effectively causing the motors to fight each other overloading the safety clutches.
I am wondering if something similar happened in this case??

BP

[Merlyn]

The one fifth rule which I quoted as not being applicable should have given the game way? Balanced rudders such as for planing craft have one fifth of the total rudder surface area ahead of the rudder stock shaft to balance the rudder and from personal experience over the years I have to say that concept really works, even when you have a lot of horse power being churned out. In fact it seems to work at its best and be really light to handle when both engines are up on the governors. Back to Pounders maybe for JK? So it would appear to me that the Tupperware dish with a block of flats mounted on it is not only handicapped by its design but also maybe it's propulsion units? Image the scenario prior to running up the Blue Peter. Which is the most important factor to be taken into consideration before singling up all lines? The Beaufort scale not only applies to all that top heavy design C of G but to the Anzipods designs and how many sets of clutch plates carried. New factors to be taken into consideration prior to setting sail? Perhaps the ships insurers together with all passengers separate insurers will load premiums for all the XO 2300 series modelled ABB pod designed vessels or send the passengers complimentary cork/ ferodo inserts with their tickets, just in case. ( for both sides, naturally ) or maybe ABB will revert to hydraulic motors instead of telling us that the new electric motors now give " total control ". Big jobs for the PR boys here perchance alround. Another interesting new concept for engineering staff might be that in order to change lower seals at sea in the pod and inflate the airbag/temp seal only split pin jobbies need apply. I. E. No big boys in the pods. They just won't fit. So if all the engineers are not split pins designed who is going to change the seals? Can you imagine,a ship like that in a rough sea, head to wind on one pod? Or worst half a pod maybe ? If I were a passenger I would constantly be sniffing the wind for that very distinctive burnt out clutch smell all of the trip. Burn out all eight sets of centre plates because of a bit of roughers and with the inserts gone and steel to steel scenario present and work out the Clinometer angle and how on earth you could get off the thing. And onto what? So we wait with baited breath for the next top secret pod failure(s) to occur, the lack of tugs big enough to cope with the huge size ships, small exit doors in the sides of the hull, excessive heights for jumping into the briny, and all that superstructure exposed to the storm and dreaded side slop factor accelerated by virtual design to ensure all present have " the trip of a lifetime " Plus six thousand plus people involved. Watch this space.

[JK]

We had issues with an AC/AC propulsion system tripping violently when working in heavy conditions. As a watchkeeper at the time, I can attest how violent the breakers used to trip, everything would go. It is when I started going grey. It turned out to be the wiring from the encoder. When the system and wiring warmed up, the impedance of the wire would change which changed the signal of the feedback.

Remember the lifeboats are an exemption to the Class Rules. They are only meant for passengers. The poor crew get to go over the stern in slides to rafts. We know how well that worked on the burning ferry.