3.2.2 The minimum freeboard at any point along the freeboard deck (Hmin) should be not less than: Hmin = LBP/40 (where LBP is length between perpendiculars)
If we employ this calculation for the Waratah:
Hmin = 465/40 = 11.6 ft. (aft Hmin = 12.64)
The Waratah had a freeboard of just over 8 ft. almost 4 ft. less than the above. This would have made the flagship more prone to seas washing over her main deck, increasing the risk of flooding either of her main hatches.
Miscellaneous Provisions for furthering Safety of Life at Sea.
22. The rules set out in the Third Schedule to this Act with respect to watertight doors and other contrivances shall be complied with in every British passenger steamer registered in the United Kingdom, and if any of the said rules is contravened in the case of any such steamer, the master thereof shall for each offence be liable to a fine not exceeding one hundred pounds.
(a) a British passenger steamer registered in the United Kingdom has been marked with subdivision load lines, that is to say, load lines indicating the depth to which the steamer may be loaded having regard to the extent to which she is subdivided and to the space for the time being allotted to passengers; and
(b) the appropriate subdivision load line, that is to say, the subdivision load line appropriate to the space for the time being allotted to passengers on the steamer, is lower than the load line indicating the maximum depth to which the steamer is for the time.being entitled under Part II of this Act to be loaded; the steamer shall not be so loaded as to submerge the appropriate subdivision load line on each side of the steamer when the steamer has no list.
One can assume that it was important the Waratah departed Durban without a list, which was the case after Captain Ilbery made adjustments. If not, the subdivision load lines on either side would have shown a discrepancy, one of which would not have met approval.
... of this Act by virtue of the last foregoing section are hereafter in this Act referred to as " load line ships," and for the purposes of this Part of this Act are divided into the following classes, namely-
(a) international load line ships, that is to say, ships of one hundred and fifty tons gross tonnage or upwards which carry cargo or passengers ;
...the load lines are in the position required by the tables used by the Board of Trade on the thirty-first day of December, nineteen hundred and six, for fixing the position of load lines.
On the 21st October, 1908, a loadline certificate was issued by Lloyd's for the Waratah.
" (5) In this section the expression 'freeboard ' means, in the case of any ship which is marked with a deck-line, the height from the water to the upper edge of the deck-line, and, in the case of any other ship, the height amidships from the water to the upper edge of the deck from which the depth of hold as stated in the register is measured."
4. In order that the required degree of subdivision shall be maintained, a loadline corresponding to the approved subdivision draft shall be assigned and marked on the ship's sides. A ship having spaces which are specially adapted for the accommodation of passengers and the carriage of cargo alternatively may, if the owners desire, have one or more additional loadlines assigned and marked to correspond with the subdivision drafts which the Administration may approve for the alternative service conditions (this strikes me as room for 'liberties'). The freeboard corresponding to each approved subdivision loadline, and the conditions of service for which it is approved, shall be clearly indicated on the Safety Certificate. Subdivision loadlines shall be marked and recorded in the manner provided in Regulation VII.
(1) The subdivision loadlines assigned and marked under the provisions of Article 5 of the Convention shall be recorded in the Safety Certificate, and shall be distinguished by the notation C.1 for the principal passenger condition, and C.2, C.3, &c., for the alternative conditions.
(2) The freeboard corresponding to each of these loadlines inserted in the Safety Certificate shall be measured at the same position and from the same deck line as the freeboards determined by recognised National Freeboard Regulations.
(3) In no case shall any subdivision loadline mark be placed above the deepest loadline in salt water as determined by the strength of the ship and/or recognised National Freeboard Regulations.
(4) Whatever may be the position of the subdivision loadline marks, a ship shall in no case be loaded so as to submerge the loadline mark appropriate to the season and locality as determined by the recognised National Freeboard Regulations.
Winter Load Line.-The Winter load line is indicated by the upper edge of a line marked W.
This loadline would differ from that for summer. Colder winter waters provide more buoyancy than warmer, summer waters:
The waterline is the line where the hull of a ship meets the surface of the water, in concept or reality. Specifically, it is also the name of a special marking, also known as the International Load Line, Plimsoll line or water line (positioned amidships), that indicates the draft of the ship and the legal limit to which a ship may be loaded for specific water types and temperatures in order to safely maintain buoyancy, particularly with regard to the hazard of waves that may arise. Temperature affects the level, because warm water provides less buoyancy, being less dense than cold water, as does salinity, because fresh water is less dense than seawater. (Wikipedia)
The Merchant Shipping Act of 1876 made load lines compulsory. However, the position of the line was not fixed by law until 1894. In 1906, foreign ships were also required to carry a load line if they visited British ports.
All of that being said, the following article reveals that all was not well with loadlines approved for commercial vessels at the turn of the previous century:
This powerful piece draws attention to the 'relaxing of loadlines' circa 1906, despite the draconian-sounding legislation. The description of the vessel 'there was no life in her movement' reminds me of observations made by Claude Sawyer on the voyage from Australia to Durban:
"It was about 10 days before we arrived at Durban that I decided to leave the ship, because I was not quite satisfied with her and the way in which she behaved; she pitched and rolled, as the case might be, so dead; she was anything but lively. She recovered herself very slowly, and stayed in the position in which she was when rolling or pitching for a long while before recovering."
"I spoke to him (John Ebsworth) about the rolling. We decided one day, accordingly, to watch the Waratah's behaviour. It was a calm, fine day, with big rollers coming straight towards us, going fore and aft. Whenever a particularly big roller came the ship did not take it as she should have done, but put her nose right into it and remained there, apparently without any life in her. Mr. Ebsworth was, I thought, rather upset, and said that it was the first time in the whole of his experience that he had seen a ship do this."
Aside from Claude Sawyer's visions, he made astute observations on board the Waratah, confirmed by another experienced seaman, John Ebsworth. The description of the Waratah's performance in calm waters is highly suggestive of a vessel which had reduced buoyancy (overloading). 'Officially' the Waratah may have passed the regulatory specifications of the time, but in reality she was too heavy. Unfortunately, in order to compensate for the GM instability created by her three superstructure decks, there was no other option but to keep her deeply loaded and 'stable' in GM terms. Lead concentrates were also employed for this specific and crucial purpose.
But perhaps more disturbing were the freeboard shortcomings. A vessel such as this, in trouble in winter seas, would be very vulnerable indeed. There had to be good reason for the 'large steamer' astern of the Harlow disappearing in such a short period of time.