Thames river crossings

Is the river flow strong enough for the new ferry to be self-acting?

I very much doubt it, given the tides are much stronger than the river flow other than around slack water (the short period around high and low water when the tide is turning). I also don't know if a self-acting ferry would have the necessary manoeuvrability to avoid other river craft. Officially, no class of boat has priority over any other on the Thames, but in practice cross-river traffic almost always gives way to users heading up or down river, and everything gives way to human-powered craft and most things give way to canal boats (as they are much lower powered than river craft).

The queues for the Blackwall Tunnel are now 7 days a week for much of the day.

There will be tolls on all the tunnels which should help traffic. The north side links with the A13 near Canning Town.

This should spread things out.

Adding additional road capacity on this scale will simply generate much more traffic and any relief of the Blackwall tunnel will the short lived. You can't argue that a link will be "green" and then also say it will massively help business and redevelopment. The latter two almost always mean far more vehicle movements because there are new places to go, new businesses that need logisitical support (lorries and vans) and employees (many will drive) plus customers (if retail or leisure busnesses) implying yet more cars. Even if the crossings are tolled (Blackwall too) there will still be a flood of traffic and then there will be more pressures to raise capacity on the main connecting roads north and south - again more capacity means more traffic and more pollution. IIRC TfL's own consultation material showed considerable traffic increases over a wide area north and south of the river as a result of new generated traffic demand.

I note some campaigners said they feel "betrayed" by the Mayor but I'm not surprised by this decision at all. The strong emphasis from Mr Khan about business and redevelopment all said to me that he was very likely to proceed with building this tunnel. All Mayors like to have some bits of concrete and metal as their "legacy" and this is likely to be part of the current Mayor's legacy to London - if he can get it funded and through the planning process!! I feel these latter two aspects will prove very tricky as campaigners will bring multiple legal challenges about the environmental impact. There were problems a long while about funding and whether some form of PFI deal (linked to the tolls) could be put together. TfL certainly don't have the budget for it.

indeed you can't fit double decker buses in the current tunnel, hence why I said you'd need to think outside the box. Amphibious buses, ferries that coordinate with buses, etc.
Just building a new tunnel wont help anybody if the buses just get stuck on the A102.

For a brief moment I had visions of D-Day! 

Sorry but a few amphibious buses (small single deckers) and ferries would not help the volume of traffic needed. The latest proposals do include a ferry from North Greenwich to the Isle of Dogs. This already runs sometimes for events as Thames Clippers has a suitable pier at their base.

The volume of river traffic is such that an under or over approach is necessary.

I was intrigued by this, (and wanted to go to Amsterdam specially to go on the Floating Dutchman!) but it ceased operations in May 2015. www.simplyamsterdam.nl/Floating_Dutchman.htm
Rotterdam's Splashtours are still taking bookings though.
www.splashtours.nl/tickets/index.php?taal=en&menu=Tickets&submenu_nl=Boeken&thismonth=8&thisyear=2017

It appears that a requirement to convert to electric (whether it was tourist boats or coaches which have to meet this new rules is not clear) proved technically unfeasible. As offroaders and fans of Scrapheap Challenge will know, Diesel engines can operate when totally submerged (provided they have a snorkel attached to the air intake!). But it suggests that a hybrid amphibious bus, let alone a straight-electric, might be very difficult to engineer.

As for designing a low floor version, this would be very difficult to achieve. The reason for this is not hard to guess - Archimedes worked it out two thousand years ago, and "ye cannae beat the laws of Physics, Cap'n" Both DUKWs and the modern Dutch amphibious tourist buses get round the problem by being of very-high-floor configuration. The entrance doors of the Dutch vehicles are so high off the ground that they are boarded using gangway steps. Duck Tours solves the problem more prosaically by providing a built in ladder. (A railway-style platform would be anbother possibility, but hardly practical on a stage carriage service on London streets!)

Any low floor version would have the passengers, and the entrance, below the waterline. This would not be a very pleasant experience for the passengers, and the doors would have to be extremely watertight - they would certainly have to be more robust than a standard bus door! And, unlike the tour buses, the doors on a stage carriage service must open and close far more often and far more quickly. In any case, most of the "below decks" space is needed for the power plant - for practical purposes there is a minimum power requirement for any vessel navigating the Tideway - it has to be powerful enough to beat the current, which can be as strong as 10 knots.

The tides create another problem as well, as the slipways would have to be usable at all states of the tide (and, when the tide is falling, they would be difficult to negotiate as they would be very slippery). DUKWs have huge off-road tyres for this reason. Amsterdam's canals are not tidal so it wasn't a problem there.

Like any multi-purpose tool, an amphibious vehicle is sub-optimal for each of its individual roles. It makes for an unwieldy road vehicle, and its seaworthiness is compromised. Better to provide quick and easy bus-ferry transfer stations.

The easier way of getting a bus across a river is to piggy back on a ferry. This is done for example at both Torpoint and Sandbanks on the south coast, but as far as I am aware has never been proposed for the Woolwich ferry, despite numerous bus services serving both piers. (Incidentally, was it ever used to transfer trolleybuses between the main network at North Woolwich and the isolated Woolwich/Dartford network? I would imagine their battery power would have been up to the job). The Torpoint ferry buses appear to have higher platforms than normal, in order to negotiate the ramps. This is obviously a hindrance to low-floor access.
www.showbus.com/gallery/sw/wntamar2.htm

Where services are frequent, it makes more sense for the "sentient cargo" to transfer bus/ferry/bus on foot - quicker as well, as pedestrians can jump the queue of vehicles waiting for the ferry. Taking a bus on a ferry is a better option if there is nowhere to park buses at the ferry terminals, or where the service is so infrequent that it would not be economic to leave a bus standing idle at the far side for most of the time.
It seems better suited to low frequency bus services where it would be inefficient to keep a second bus on the far side waiting for the ferry.

AFAIK the Woolwich Ferry has never conveyed buses or trolleybuses in service. Presently, the ferry service is too infrequent and loading and unloading times too long for a cross-river bus route to be at all reliable. Neither problem is solvable using the current infrastructure, but if designed with bus carrying in mind from the start, they are not at all insurmountable I'd have thought.

As for the design of amphibious buses - yes they would need significant development work to be practical, but given some time, money and expertise I have little doubt that the problems could be overcome. I can't give you answers now as I don't have the time, money or expertise, but my point is that the problems caused by the Blackwall Tunnel need to be addressed with a wholistic approach and outside the box thinking, not just building a new road tunnel whose main impact will be to significantly worsen air quality and, at best, move traffic congestion slightly.

Not saying it's impossible, but I am intrigued by what such an amphibious double decker would look like. Archimedes cannot be gainsaid. If the lower deck is anywhere near street level on land it would inevitably be below the waterline when afloat, and keeping any doors watertight would be a serious engineering challenge. It might be possible to design a bus that was boarded from the upper deck (some double deck trains are like this), but it would be an interesting exercise to design suitable bus stops for them!

Indeed both the DUKWs and the Dutch tour buses are effectively boarded at (and driven from) upper deck level - but they have no lower deck!)

Easier to fit the bus with a flotation device to make the crossing, (a "Fitted External Roll-on Roll-off Yoke for Bus Operation Across the Thames"). Even easier to let the sentient cargo transfer to and from such a floating device on foot.

And how exactly are London's small businesses and service industries expected to cope? The plumber, the builder, the delivery driver are not going to find PT or cycle links useful are they. The whole point about additional river crossings is nothing to do with enabling car use - is to enable business to not have to rely on the congested / restricted crossing points of Tower Bridge or the Rotherhite / Blackwall Tunnel or go all the way out to the congested Dartford crossing.

Previously suggested ideas of bridges at Becton - Plumpstead and Rainham - Thamesmead would meet this requirement, unlike cycle / rail options. By all means make them single carriageway with dedicated bus / DLR / Overground options to prevent swamping of roads on either side but don't be delusional in that they are not required if you want developments along the river to thrive. West London has lots of bridges - mostly small single carriageway affairs giving lots of connectivity to each side, why cannot East London have the same rather than being reliant of massive and congested detours

IIRC one of the sightseeing operators (Culture Bus? Ensign?) tried out a Docklands tour including a Woolwich ferry crossing in the late'80s or early '90s.

I doubt if it would be possible to design a double-deck amphibious bus able to run through the streets of London and stable enough to operate in a tidal river.

Hardly bigger than an SUV.

The logic for the possible Overground extension should be a road crossing as well. Joined up thinking is needed. Local traffic could have lower tolls.