User Contributed Dictionary
Extensive Definition
In ship design the Tumblehome is the narrowing of
a ship's hull with greater distance above the water-line. Expressed
more technically, it is present when the beam at
the uppermost deck is less than the maximum beam of the
vessel.
A small amount of tumblehome is normal in many
designs in order to allow any small projections at deck level to
clear wharves
(Pursey p. 218).
Tumblehome was common on wooden warships for
centuries. In the era of oared combat ships it was quite common,
placing the oar ports as far abeam as possible. This also made it
more difficult to board
by force, as the ships would come to contact at their widest
points, with the decks some distance apart. The narrowing of the
deck above this point made the boat more stable by lowering the
weight above the waterline, which is one of the reasons it remained
common during the age of cannon-armed ships.
It can be seen well in steel constructed warships
of the early 1880's when the United
States and most European navies
began building steel warships. France was
predominately strong in promoting the tumblehome design in their
warships, and sold their newly constructed pre-dreadnought
battleship
Tsesarevich to the Russian
Imperial Navy in time for it to fight as Admiral Wilgelm
Vitgeft's flagship at the
Battle of the Yellow Sea on 10 August
1904. However,
the five follow-on Tumblehome designed s, which had been built in
Russian yards to Tsesarevich's basic design, fought the only
decisive steel battleship fleet action in naval history on
27 May
1905 at
Tsushima.
The fact that three of the four (the fifth battleship, the Slava
was not completed in time) 'tumblehome' Borodino class battleships
were lost in this battle, resulted in the discontinuing of the
tumblehome design in future warships for nearly all navies.
A degree of tumblehome also facilitates paddling
in a canoe or kayak (Mather, 1885), while a greater degree of flare
(its opposite) accommodates more cargo (Vaillancourt).
Modern warship design
tumblehome in French:
Frégatage