Trans RINA, Vol 152, Part A4, Intl J Maritime Eng, Oct-Dec 2010
the frightful looks and behaviour of the man who was at the helm when the vessel broached to. Although he was a very experienced seaman, he exclaimed calling on his God and Saviour -we are gone! we are gone! nothing can save us!”
The broaching-to amidst squall of a corvette that was earlier firing against his ship is described by an unknown author in the magazine “The Casket” [39]:
“The corvette, moreover, was a wreck, stripped of every
thing, and broaching to, with the waters rolling like a cataract over the weather side, and her horror struck-crew hanging in affright in the shrouds, and whenever they could clutch a rope.”
In a similar magazine about literature, philosophy and religion (“The dial”) we find the following sentence, referring to the travel of a brig from Boston to Jamaica [40]:
“...ten hours since the commencement of the gale, and
the winds and the sea were still increasing in violence. Directly there came over us a sea so very heavy as to cause the brig to “broach to” (fall into the wind) and throw her down on her side. But her cargo being solid did not shift, she therefore righted immediately.”
A life-boat’s (under sail) capsize is discussed in the earlier mentioned letter to the Times by Ward [27]. Written in defence of having sails on the life-boats of the time, in the letter is argued that the accident should be attributed to the action of the sea alone:
“She had been to a wreck at a distance of six or eight miles from the land, and was on her return in the night time, running before the wind and sea, when, on nearing the shore and getting within the broken water, a heavy breaker threw her stern up, and buried her lee gunwale under water; she then broached to, broadside on to the sea, and was turned over by the following wave. The wind had previously fallen light, so that the accident was occasioned by the action of the sea alone.”
It should example:
° In the search for a North-West passage from the Atlantic to the Pacific [41].
° 5.
In the tales of the voyages of the ship H.M.S. Samarang in the islands of the Eastern Archipelago [42].
CONCLUDING REMARKS
The motive behind the research presented in this paper was to find out whether there is anything to be learnt from what was empirically perceived in the past about
2. 3. be noted finally that, short narratives of legendary references
expressing the fear of broaching-to have appeared in several
expeditions as for
the erratic type of ship behaviour known since many years as “broaching-to”.
It came out that, phenomena such as bow diving and surf-riding have been regarded, for at least two centuries, to be closely connected with the occurrence of broaching-to. Thus, their relevance is not a recent discovery. The scientific basis of these phenomena and their dynamical contribution to broaching-to are matters considered nowadays as resolved. Yet there account in ship design is still very limited.
Broaching-to was mostly feared when approaching a steep shore. Nevertheless, several records of broaching- to incidents away from shore have also been identified.
Whilst wind was initially considered to be responsible for broaching-to, gradually a more balanced view was developed as regards the effect of wind and of waves. It seems that the controversy about the use of sails on lifeboats contributed to the better understanding of the effect of waves, at least for boats of small size. It is worthy to note however that, whilst nowadays we have a solid grasp about the role of waves, our
scientific
understanding about the role of wind in the occurrence of broaching-to of a sailing boat is not on a similar footing.
The recommended strategies for avoiding broaching-to were mainly: either to try to go ahead of the weather, or, adopt an action cycle where, by use of the oars, the boat is slowed down at waves’ down-slope and is speeded up at the up-slope. In today’s language, this would mean to work against the development of nonlinear surging behaviour; where the ship is accelerated as it passes from the wave crests and becomes prone to being captured into surf-riding at a nearby wave trough.
Ropes, and later on drogues, were used in order to increase resistance and slow-down the boat so that to avoid, what we would call in modern IMO vocabulary, the dangerous speed zone [43]. Technology and scientific knowledge have advanced; yet the essence of the recommended practice has remained.
6. 1.
REFERENCES GRIM,
O., DU CANE, Das Schiff in vor achtern
auflaufender See, Jahrbuch STG, 45, pp. 264- 287, 1951.
P. & GOODRICH, G.J., The
Following Sea, Broaching and Surging, RINA Transactions, Vol. 104, pp. 109-140, 1961.
MOTORA, S., FUJINO, M., KOYONAGI, M., ISHIDA, S., SHIMADA, K. & MAKI, T., A consideration occurrence
on the mechanism of of broaching-to phenomena.
Selected Papers in Naval Architecture and Ocean Engineering, no 150. Tokyo, Society of Naval Architects of Japan, 1981.
©2010: The Royal Institution of Naval Architects
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