Tacet

Looks like he tried two leads and power supplies.

You would be making a soggy mess, Anything that leaks through an intermediate gate will end up, for a while at least in the lock below. So if you are following a boat up a Bingley-style staircase after a mid-reasonable interval the top lock will be a bit down and the intermediate locks full as leaks-in will largely equally leaks out. So draining the second from bottom lock into the bottom lock will over fill it. Assuming it is not overtopped, the level between the two will be on the high-side and increasingly so as you ascend. If the top lock was well down from full, you might get away with it at the final point but the chances are you would have wet feet before then A fast way to ascend a Bingley-style staircase (when no-one important is watching) and all chambers are at the low level (i.e. the previous boat has descended) is to draw all the intermediate and the top paddles at then drop each set (working uphill) when the relevant chamber has made the correct level. It's very easy to become confused at to the correct level or not be in the right place at the right time When filling a drained pound, Mrs Tacet's conscience is such that he will not draw paddles at both ends on the next lock; water has to be let down, one lockful at a time.

I was tempted to suggest the narrow staircase at Stourport - but it is the upper chamber that has the side weir, presumably to regulate the basin. The first lock on the Wey, with the additional gates sometimes used to lift boats over the cill is an example - but not a conventional one Putting aside 1st Ade point about differing lengths/widths, the use of a staircase will tend to move the two rises towards each other. I.e. if the top lock has an ostensibly greater rise, when its contents are discharged into the lower chamber it will leave the level higher than the bottom of the coping stones - and the top chamber will not be as low as otherwise. There shouldn't be an issue on draft over the lower cill. But if the masonry is insufficient to accept half the total rise, it will be overtopped. So the hydraulic rise will always be the same for each chamber (assuming other factors remain constant) - and the masonry etc needs to allow for it, and a little bit more for canal level changes etc. Incidentally the same applies to a canal which, in concept is one long staircase until the summit/sump is reached. But there are a lot more factors in play in the longer pounds - with weirs, inlets, boats changing defections, pairing up etc. The effect is more obvious on short pounds which rise and fall as adjacent locks are drawn

It depends, as has been said, the manner in which it might fail. The box section will be stronger when acting as a beam (more meat in the lowest part). The angle will better resist the the bolts being torn through or the holes elongated (more meat where the screws passes through). There will not be much in it (aka I don't know) which better resist being pushed out of square by the overhanging load = 2 @ 3mm v 1 @ 5mm. D squared seems to come into calculations fairly frequently and this might favour the angle?

You did say not to over think it. But you also said it makes absolutely no difference (your bold) where along the boat you adjust the ballast port and starboard (athwartships) and it applied to any shape boat. Then it was subject to being symmetrical along its longitudinal axis - which I accept is very common. Now it is subject to (I think) the boat being symmetrical across it mid section - which is uncommon. Most narrowboats and widebeams boats are not much different front and back at the waterline - but even by design, there is usually a difference particularly if a counter stern comes into play. So, in practice no appreciable change to list consequent upon where, fore and aft, the ballast is positioned. But in theory, there is a difference unless the boat is symmetrical in plan about its central point. I shall devote the time saved in not building a triangular boat towards thinking whether being trimmed by the head (or stern) has any effect.

OK. I am not sure myself, so I will (soon) let it go but it seems to me to be a 3D issue. My theoretical concern is that by moving the force along the centreline it changes the trim and thus the boat is not effectively symmetrical about the fore-and-aft centre line. A triangular boat (in waterline plan) would be effectively wider in beam as the force is moved towards the wide end and the narrower end rises. Maybe I will make triangular boat and try it in the pond.

So here is my boat: It is a bit odd insofar as it has an asymmetric cross section - a little like a confused aircraft carrier. For the front part, the element below (nearer) the waterline is on the port side and at the stern it is on the starboard side; the other side can be taken as above the waterline at all times. When I move ballast from fore to aft, the boat goes bow or stern up, of course. It is made even-keeled by ballasting at bow with the stern end elevated - possibly even above the water. I move ballast aft along its longitudinal centre line (it is symmetric in plan - anything else would be silly!) to the stern. It is now bow-up, possibly even out of the water. Will it remain even keeled? As I say, you may be correct. I have seen Blackrose and it is not entirely like my example but it does have varying cross sections and shifting ballast fore-and-aft will change the effective cross section for displacement purposes. Not much. Not enough to notice.

Not necessarily, I think. It must relate to displacement. Assuming Blackrose is symmetrical about its longitudinal axis and forms a rigid box, it ought not to make a great deal of difference. Where it gets complicated is that in moving ballast fore-and-aft, the displacement per degree post-starboard might change. In an extreme (and impossible) example, if it became so bow-up that pretty much only the narrower swim area was below the waterline, it would require less weight to change the athwartships trim by one degree. I see Murflynn disagrees - and he may be correct! I suggest you check the list whilst standing to one side at the bow and then again at the stern. You will need a reference point. Ideally you would leave the spirit level (or automatic level) in the same, say midship, position throughout so you will need a way/someone to read it. My guess is that there will be no measurable difference.