So i Guess from the brief outline, Lee attacks Washington with Royal Navy support? Any one care to outline the defenses of DC against both Land and sea attack at that time?
At sea it's essentially
Fort Washington, a rather weak third system fort, and a few earthwork batteries.
The defences were characterised by British observers as very weak, and one observer showed one of the garrisons that the forts weren't even secure against cavalry.
He
was remarkably civil and gave me passes and
a letter to take me over the fortification[s},
{and] camp around Washington. The city is
surrounded at a radius of some 3 to 5 miles
with a series of detached forts and earth
works making in all about 35 to 40 miles.
These works are not particularly well placed
nor is the design of much good. Many are
too small to be of any real service, and although
manned by some 80,000 men, I believe
good troops would very shortly force
them. The Confederates are not, however,
good enough for this, and consequently the
works render Washington impregnable for
the time, which is all that is required of them.
Even if the Confederates did take the Forts
on the south side of the river, Washington
itself being on the North would still be safe
from everything except shelling, at moderately
long range-Cincinnati is fortified in a
similar manner but the general plan considerably
worse, indeed several positions of their
lines could be taken not only by good infan-
try, but by a sudden dash of well mounted
cavalry. However, there is good excuse for
this for a great portion of the works were
hurriedly thrown up by civilians-I could
not help pointing this out to the chief of the
staff, and at last he acknowledged I was right
especially after I had ridden one of his own
cavalry man's horses (I think the worst saddle
for any real riding) 'clear over the ditch,
and parapet charged in amongst his men
who were absolutely aghast at the idea of
cavalry charging even the slightest obstacle.
The Southern cavalry are the better than the
Northern but still as cavalry they are poor
enough. The cavalry on both sides, but more
especially the Northerns, are merely mounted
infantry. They are not taught to use the
sword at all, and indeed several regiments can
muster but few swords anyway. They are
armed with rifles and revolvers, the consequence
is that they never charge or get well
amongst the infantry, (the only chance for
cavalry) but dismount and skirmish, and of
course get beaten as all cavalry must, in that
sort of work against Infantry. Now and
then a regiment may charge upon a sleeping
picquet or a solitary company when they can
come upon them unawares and un-supported,
or on the march. This is then set down as a
billiards {sic) charge, although really not a
shot has been fired on either side or a man
killed.?
(R. A. Preston, A Letter from a British Military Observer of the American Civil War, Military Affairs, Vol. 16, No. 2. (Summer, 1952), pp. 49-60.)