In some cases, the ship was merely aground and not sinking or breaking up, the weather was tolerable, and a safe haven was close by. In that case, the lifeboats merely served to ferry people to the shore or rescue ships, and could make multiple trips, so their limited capacity was merely an inconvenience.
But a shortage of lifeboat capacity meant that if the ship was sinking fast, some would be in the water, not the boats. Sometimes the crew controlled who got to go into the lifeboats, and other times it was every person for himself (or herself). On the Titanic, class (and hence berth deck) made a difference—61% of first class, 42% standard class, and 24% third class (and crew) survived. Gender, too; 20% of male passengers and 75% of female passengers survived (titanicfacts.net).
On the other hand, on the William Brown (1841), thirty-one passengers were left on the foundering ship. Another thirty-two made it onto the longboat, but when that began to leak, and it started raining, the nine crew members in the longboat decided to toss out fourteen of the seventeen male passengers, and two of the female passengers. In United States v. Holmes (1842), one of the longboat crew was subsequently tried for homicide, and the court declared that the sailors had the obligation to make their safety secondary to the safety of the passengers and hence, provided there be left enough sailors to manage the boat, "the supernumerary sailors have no right, for their safety, to sacrifice the passengers."
The 1912 Titanic disaster prompted the adoption of the 1914 SOLAS. The chapter on life-saving appliances was applicable to passenger ships on international voyages. While the details of the 1914 SOLAS, and subsequent revisions, are probably not in Grantville literature, I think it helpful to mention some of their requirements as I am sure some up-timers will think along similar lines when it comes to proposing ways to reduce loss of life in maritime disasters.
The 1914 SOLAS provides that "at no moment of its voyage may a ship have on board a total number of persons greater than that for whom accommodation is provided in the lifeboats and the pontoon life-rafts on board" (Art. 40, but see regulation XLII). The boats and rafts had to be stowed so they could be launched "in the shortest possible time," and so a large number of people could be embarked on them "even under unfavorable conditions of list and trim." In particular, the davits (or equivalent) had to be capable of lowering boats with their full complement of persons and equipment, despite the ship listing 15 degrees (Art 49).
Several different types of lifeboats and liferafts ("pontoon boats") were contemplated (XXVII-XXXIII). Class 1 boats had entirely rigid sides, while class 2 were partially collapsible and thus easier to stow. The boats were required to have internal buoyancy (provided by water-tight air-cases, and these were preferably at the sides of the boat or raft). Those of class 1A relied solely on internal buoyancy (with one cubic feet buoyancy for ten cubic feet capacity), while class 1B and 2A could rely in part on external buoyancy (cork or any other equally efficient material, but not "rushes, cork shavings, loose granulated cork or any other loose granulated substance, or by any means dependent upon inflation of air").
Rafts (classes 1C, 2B, 2C) had to be fitted with one-way valves for quickly clearing the deck of water.. They also had to be reversible, fitted with bulwarks to provide at least six inches freeboard when fully loaded, equipped with air-cases or equivalent buoyancy (3 cubic feet per person) and to be capable of being "thrown from the vessel's deck."
The 1914 SOLAS regulations (XXXIV-XXXV) assessed passenger capacity based on either the cubic volume (one person per 9-10 cubic feet) and deck surface area (one person per 3.35-3.5 square feet), whichever yielded the higher (!) passenger capacity. Cubic volume was determined by "exact measurement" (at three sections, then applying Stirling's rule, or any alternative method of the same accuracy, rather than by a coefficient formula such as 0.6 * length * breadth * depth. There was also a penalty to the volume calculation if the boat were too deep.)
The registered length of the ship determined the minimum number of sets of davits, of open boats of the first class, and the minimum capacity of lifeboats in cubic feet (XLIII).
All of the lifeboat types set forth in the 1914 SOLAS were of the open type. The 1974 SOLAS required lifeboats to be partially or totally enclosed. Obviously, this was to provide more protection from the elements. The reason for allowing partially enclosed lifeboats was that those are easier to board. The totally enclosed lifeboats were required to be self-righting.
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As I mentioned earlier, several up-timers served in the US Navy. Typically, late twentieth-century USN vessels were equipped with inflatable liferafts rather than rigid-hulled lifeboats. (The larger ships did carry auxiliary craft that could serve in a pinch.) The kind used in the Vietnam War era were inflated by carbon dioxide and had a drop-down floor (NAVSHIPS).
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There are a few survival craft requirements of the 1999 CG regulations that I want to mention.
--Liferafts must be arranged so they can be dropped into the water from the deck on which they are stowed [199.03].
--Each liferaft must have a capacity of six persons or more [199.201 and 199.261].
--For passenger vessels, with some exceptions, the total survival craft capacity must cover at least 125% of the total people on board, and the lifeboat capacity on each side must be at least 37.5% [199.201]. There must also be at least one lifeboat (or rescue boat) for every six liferafts (nine for a short international voyage), for marshalling purposes [199.203]. It must be possible to launch enough survival craft to disembark all people on board "within a period of 30 minutes from the time the abandon-ship signal is given" [199.245].
--Lifeboats must be open boats with rigid sides having internal buoyancy (typically from polystyrene or polyurethane) only. They may be made of steel, aluminum, fibrous glass reinforced plastic or other approved material (no mention of wood!). One cannot carry more than 150 people and usually those carrying more than 100 are motor-propelled. For lifeboats of normal proportions, the cubic capacity is determined as 0.64* length * beam * depth. The number of cubic feet required per person depends on the length and ranges from ten to fourteen [160.035].
--For cargo vessels, lifeboats must be totally enclosed! For cargo vessels at least 85 meters in length, there must be enough lifeboats on each side to carry off everyone on board. Additionally, either there are enough liferafts for everyone on board and they are stowed in a position providing for easy side-to-side transfer at a single open deck level, or each side has enough lifeboats for everyone on board. Shorter cargo vessels are not required to carry lifeboats, but must carry enough liferafts on each side for everyone on board [199.261].
--It must be possible to launch enough survival craft to disembark all people on board within a period of 30 minutes for passenger vessels, and 10 minutes for cargo vessels, from the time the abandon-ship signal is given [199.245, 199.280]. Also, they must be stowed as near the waterline as is safe and practicable (although at least two meters above), and sufficiently ready for use so that two crew members can complete preparations for embarkation and launching in less than five minutes. Lifeboats must be stowed as far forward of the propeller as practicable and protected from heavy seas. Liferafts are stowed so they can drop into the water, i.e., either outboard of the rail or bulwark, or there is an opening allowing them to be pushed directly overboard [199.130].
--There must be enough survival craft capacity so that if the largest one on either side is lost or unserviceable, everyone on board can still be disembarked on that side.
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Survival Craft Equipment
Per 1914 SOLAS, both boats and rafts were required to be equipped with oars and related items, one kilogram of food and one quart of fresh water, in watertight receptacles, for each person on board (seems low to me, but this was written at a time when rescuers could be summoned by radio!), a vessel containing five liters of vegetable or animal oil (for quieting the surrounding water), a watertight box of matches, a number of self-igniting "red lights," a
sea anchor, a tow rope, and a lifeline becketted around the outside. Boats were also required to have a compass, two hatchets, an oil lamp, and, if they didn't have a motor, a mast and sail (XL).
The 1999CG regulations have additional requirements, notably a bailer, bilge pump, boathook, can opener, dipper, fire extinguisher, fishing kit, flashlight, heaving line, knife, boarding ladder, signaling mirror, manually operated pump, radar reflector, rainwater collection device, repair kit (if an inflatable), sea anchor, searchlight, seasickness kit, smoke signal, sponge, thermal protective aid, tool kit, and whistle. One unit (2390 calories) of food and three liters of water (fifteen for liferaft) are required per person [199.175].
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Launching and Loading Boats
Launching appliances transfer the boat from the stowed position to the water. The most common sort of launching appliance uses tackles, falls, and a pair of davits. The davit is a crane that suspends the tackle over the water.
Pictures of twentieth and even late nineteenth-century ships may provide insights as to how davits are constructed.
Davits were first used to hold whaleboats on ships engaged in the Greenland whaling trade, possibly from the early 1600s, although they weren't migrated to warships until much later (Harland 284). On the HMS Victory, the davits were simple baulks (wooden beams), hinged at the deck end and held by lines (topping lifts) at the outboard, tackle-holding end. The latter were steadied by fore and aft stays, and a jackstay between the two outboard ends."Lifelines" were suspended from the jackstay; the boat crew could grab these to transfer their weight temporarily from the boat to the davits (285).
The radial davit was a metal bar in the shape of a hanging post with a rounded corner, with the horizontal limb holding the tackle. The fore davit was pivoted around its vertical axis, by means of turning-out gear, to bring the bow of the lifeboat outboard between the davits and then the aft davit was pivoted to move out the stern. It typically took six men to work a radial davit and it was intended for relatively light boats.
The quadrantal davit (Welin, 1909) is pivoted near the foot, with the pivot held above the deck by a sturdy, heavy frame. The foot acts as a counterbalance as the davit is inclined to bring the tackle end of the arm outboard. In addition, the pivot bar itself moves outward on a worm drive built into the frame. This davit was designed for use on warships in which the lifeboats were stowed on superstructures some distance inboard.
Gravity-type davits have a gooseneck profile, and are spanned together. The curve part of the arm parallels the curve of the boat side, cradling it. The base of each davit has two rollers riding on a track. When the davits are released, they roll down the tracks, which carry them first obliquely and then directly downward. At the end of the track, the lead rollers act as hinges, and the hook end pivots outward. Gravity davits can be operated by a single crewman. See generally USBNP 52ff; ArmyHCCH 227ff.
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The "falls" (lines) running over the tackle were originally manila rope but this was replaced with wire. They were stowed on reels, or flaked (loosely coiled). While they can be eased or drawn by men holding the fall, the lowering or hoisting motion is smoother and safer if the falls are winched.
With independent falls, lowering a boat could be a five man job—two on each fall, and a fifth to watch the descent (Schat452). It was also easy for one fall to be paid out faster than the other, inclining the boat. So common drives were developed. Also, with hand-operated falls, there was the chance that the operator could lose his grip, and so some sort of automatic brake is desirable.
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When a lifeboat is launched down the side, there is the danger of it running afoul of protuberances on the hull, or of being stove in against the side of a rolling ship. "Schat Skates" (late 1920s)—curved iron tracks with wood lines that follow the line of the lifeboat from its gunwale to its keel, placed on the inboard side of the boat—may be used to protect against these problems (Richards).
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1999CG requires a launching appliance when the embarkation station is on a deck more than 4.5 meters above the waterline [180.150]. Launching appliances had to be "arranged that the fully equipped survival craft or rescue boat it serves can be safely launched against unfavorable conditions of trim of up 10 degrees and list of up to 20 degrees" either with just its operating crew or with its full complement. They must also be capable of recovering the lifeboat with its crew. They must not depend "on any means other than gravity or stored mechanical power which is independent of the ship's power supplies to launch. . . ." They are designed to require minimum maintenance, and that on readily accessible elements. There are structural strength requirements with a high safety factor.
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There are basically two choices for getting people onto the survival craft, load-launch or launch-load. If the latter, then you have to get the people down from the ship to the boat, probably under rough sea conditions. The simplest means is an embarkation ladder, and modern ones use manila side ropes and hardwood steps. It is essentially a traditional Jacob's ladder. Ideally, there would be spreaders to keep the ladder from twisting and trapping the user against the ship's side.
"Marine evacuation systems" are a lot fancier, e.g., an inflatable slide and floating platform. We aren't likely to see those anytime soon.
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Prepositioned Floating Shelters
During WWII, the Luftwaffe dropped Rettungsboje (rescue buoys) in fixed locations within the English Channel for use by downed flyers. The improved version (1940) had a signal mast (with a light, flags, and radio antenna), a cabin equipped with storage batteries, medical supplies, clothing, fresh water, food, a stove, signalling equipment, and double-deck beds (for four occupants), and a "tubular" lifeboat for transferring the airmen to a rescue vessel. The British deployed a similar contrivance, the "Air-Sea Rescue Float," along bombing routes (Wikipedia).
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Personal Flotation Devices (PFDs)
There are basically two types of PFDs, those that are worn or carried by the seafarer before immersion (life jackets, vests and belts), and those tossed to one already in the water (life buoys).
While it is possible to float in water without a PFD, the PFD provides extra buoyancy to help keep your head above water. Modern Type I (offshore) adult lifejackets are required to provide at least 22 pounds buoyancy, and type II (near shore), 15.5.
PFDs may be inherently buoyant (i.e., containing cork, balsa wood, kapok, or plastic foam), inflatable (with air or other gas), or a hybrid of the two.
PFD Flotation Materials
Inflated skins. A gypsum wall panel relief found at Nimrud, and dated to about 860 BC, shows the Assyrian army of Ashurnasirapal II crossing a river, some using inflated skins (British Museum). Other ancient soldiers resorted to similar expedients for water travel, and the inflated skins could be the goatskins used normally to carry water, or oxhides used as tents. Sometimes several skins were used together to provide additional buoyancy to a wooden raft, as can be seen on Trajan's column (105 AD), depicting Romans crossing the Danube (Vaucher).
Cork. Cork has a density of about 20-25% that of water (CITE) and consequently is substantially more buoyant than the woods used in ship construction. In 1538, Wynmann wrote a Latin treatise, Colymbetes, on how to teach swimming. The reason for mentioning it here is that Wynmann said that if a student wanted to practice without a teacher, they could go into water no deeper than midchest and use a flotation device, which could be "crafted from reeds, cork or two inflated leather bladders" (McManamon; Tabaczek-Bejster 263). However, Wynmann said nothing about the possible utility of such devices for saving seamen from drowning.
In 1758, John Wilkinson proposed to the Royal Society that seamen be furnished with cork jackets, which he had first made in 1757. He considered these to be superior to the simple cork floats used by those learning to swim, since there had been fatal accidents when the water had wrested these away from the learner (20).
He took this
proposal to the general public in The Seaman's Preservation (1759). In 1765, John Wilkinson reported experiments to determine the buoyancy of cork in fresh and salt water, and "the specific quantity of cork necessary to sustain a man in the water." He found that it required a little more than 12 ounces of cork to keep above water a man that was 5'2" and 104 pounds. The same year, he also received an English patent on cork jackets or waistcoats. His concept was that cork would be cut into pieces and sewn in. He recommend that the pieces be somewhat rounded for greater comfort, and noted that the "greater their number is the smaller they will of course severally be, and of consequence the more complyable to the motions of the body of the wearer." Several versions of the jacket are depicted in his book (WilkinsonSP 22-27, 38). One proposed feature was tapes on the hip of the jacket that could be tied around the thighs so that the jacket not ride up against the armpit because the jacket was more buoyant than its user.
Wilkinson mentions two objections made to providing cork jackets. First, that seamen would be encouraged to abandon ship in time of danger sooner than they should. Second, that the cork jacket would make it easier for impressed men to desert, at least when the ship was near land (WilkinsonSP xiii).
A sailor reported to Wilkinson that in 1760, the frigate he was on deliberately ran aground on a sandy beach to avoid a worse calamity, and he "leapt off the weather fore-chains with my cork-jacket on." The sea was so rough that he was rendered insensible, but the cork jacket kept him buoyed up, and the sea and wind drove him onto the shore. He noted that eighteen of the crew drowned, including the best swimmers, these being unable to cope with the mountainous seas experienced (xvii). The jacket in question weighed three pounds, of which the cork contributed one pound. Wilkinson commented that a jacket for a middle-sized man, made of old canvas, would cost no more than five shillings (xix). In 1763, the Royal Society recommended to the Admiralty the adoption of cork jackets.
Grantville Gazette Volume 93 Page 12