STEAM-SHIPS FOR THE CHANNEL PASSAGE. 
11 
Another proposal, which has been much before the public, is 
that of Mr. S. J. Mackie, C.E. This is a double-ended and 
flat-bottomed boat, 400 feet long, 90 feet broad, and drawing 
6 feet 6 inches of water. A section of it is given in Fig. 3. 
B and B' are rectangular waterways going right fore and aft, 
differing from that in Captain Dicey’s plan by having a bottom 
as well as a top and sides, and in there being two of them, in- 
stead of one central canal. Mr. Mackie’s mode of propulsion 
is by two or three pairs of paddle-wheels working in the rectan- 
gular waterways. He claims, as the advantage of his design, 
great steadiness at sea, ample and well-distributed space for 
the accommodation of passengers, great longitudinal and 
transverse strength, and the absence of any projections which 
could receive injmy from waves or piers. He also expects to 
attain high speed. I believe his vessel would realise all that he 
claims, except speed, but that no steam power whatever could 
give her speed with such propellers. A paddle-wheel working 
in a closed tube would do more churning than propulsion ; and 
as to placing two or more paddle-wheels behind the first, I 
think they are more likely to impede it than to do any useful 
work of their own. I have the highest personal respect for Mr. 
Mackie, and I have come to this judgment regarding his scheme 
with much regret ; but I am sure he would be the last person 
to wish that I should suppress my opinion, advisedly formed. 
At the annual general meeting of the Institution of Naval 
Architects in March, 1871, Mr. Michael Scott, C.E., brought 
forward a plan for controlling the motion of vessels for the 
channel passage, by the judicious use of water ballast. He 
proposed that the vessels should leave and enter the ports in 
light trim ; but that, as soon as they got into deep water, their 
displacement should be altered by the admission of sea-water 
into closed compartments, in such measure as to make the 
ship’s behaviour as easy as possible. This plan may seem rather 
bold, on the face of it ; but there is very little doubt that it 
could be successfully worked, with a little attention and expe- 
rience. The quantity of water required could all be pumped 
out in a few minutes, on approaching the harbour. It must be 
confessed that it is rather an artificial way of meeting the dif- 
ficulty, and that it falls under the suspicion of being “too 
clever by half.” Still the plan is theoretically right, apart 
from the somewhat ticklish character of the adjustment. I 
do not think I should have recourse to such a plan, for myself, 
until the more direct method of Mr. Bessemer had been found 
to fail ; but, failing that, it may be worth reverting to. 
At the same meeting, Mr. Evan Leigh, of Manchester, 
brought forward a proposal for a channel steam-ship, which 
may be said to bear a rough likeness to Mr. Mackie’s proposal. 
