US 3222700 A
Description (OCR text may contain errors)
Dec. 14, 1965 R. s. SMITH 3,222,700
INFLATABLE LIFERAFTS Filed June l, 1964 2 Sheets-Sheel'l 1 "Rax SrAuLsy Smm INVBNTOI.
Dec. 14, 1965 R. s. SMITH 3,222,700
INFLATABLE LIFERAFTS Filed June l, 1964 2 Sheets-Sheet 2 ,35 VTT# IMLI 542% 28) l a C21 l Ll REX STANLEy 5mm INVENF'OR.
United States Patent Olice of Man Filed .lune l, 1964, Ser. No. 371,601 3 Claims. (Cl. 9-11) This invention relates to inilatable liferzafts of the type designed to car-ry several persons and whose basic structure comprises a rflexible impermeable floor and protective canopy both marginally united to an inflatable tubular gunwale, the canopy being :adapted for erection upon tubular supporting means which may be inflated simultaneously with the gunwale.
Lifferafts of the type aforesaid are nowadays compulsory equipment on certain sea-going vessels as a supplement to conventional lifeboats, their chief advantage being that they can be stowed in an exceedingly small cornpass until required and can be launched, if necessary, in a matter of seconds even under conditions (such as the existence of a heavy list on the vessel) which would render the lowering of a conventional lifeboat difficult or impossible.
The normal method of launching such a liferaft is to throw the same overboard while packed in a protective valise or rigid container adapted to be burst open and discarded when `self-inilation of the liferaft is br-ought about through the medium of a painter line held on board the vessel and connected to gas-release mechanism associated with the raft.
Such a method has obvious disadvantages in the case of high-freeboard vessels carrying passengers (for example, elderly persons, women and children) who cannot safely be called upon to drop or climb down into the water and make their own way into a liferaft which is probably floating at some distance from the vessels side.
It has therefore been proposed to utilize a form of liferaft which, when inflated, can be loaded at deck level and thereafter lowered in much the same manner as a conventional lifeboat.
The liferafts hitherto used in this connection have had a circular lloor united to the lower of two superimposed gunwale tubes and carrying an inflatable central post which supports like a bell-tent a canopy attached to the upper gunwale tube.
Webbing bridles are secured to the central floor area at opposite sides of the post, while similar bridle-s are led beneath the canopy to diametrically-opposed external flaps on the gunwale, the bights of all these bridles projecting through an opening at the canopy apex and being engaged in a shackle which can be hooked to a single fall associated with a suitable davit or derrick.
While the raft above described has been successfully launched with a full complement in the course of harbor and sea trials, it is felt that its loading in an emergency may be hampered by its circular planform which permits it to rotate upon its axis to some extent when suspended, no matter how securely it may be bowsed to the side of the parent vessel. Experience suggests that nervous passengers about to board the suspended raft are likely to be deterred by the resultant continuous oscillation of the canopy ent-rance -opening relatively to the vessels deck, and by the fact of their being able to see the water through the gap on each side of the rafts point of contact with the vessels side.
Further drawbacks 4of the known arrangement are that the conical form of the canopy limits the entrance opening to a width capable yof `admitting only one person at la time, and that while the raft is suspended the sag of the flexible lloor causes the occupants to gravitate towards the central post BZZQM@ Patented Dec. 14, 1965 The object of the present invention is to provide an improved form of raft which while equally satisfactory for lowering by a single fall will not possess the aforesaid loading and other drawbacks of the known raft.
According to this invention, an inflatable life-raft of the type referred to and adapted for lowering by means of a single fall in inflated condition, is built to an oval planform with opposed part-s of its gunwale united by an inllatable tubular thwart and two inflatable tubular arches which are connected to longitudinal tubes at opposite sides of the rafts center-line, the said tubes dening the upper edges of closable entrance openings in the canopy supported by this inflatable superstructure, which :also assists the tubular thwart to brace the raft against the pull of suspension bridles extending to its iloor and gunwale.
Preferably there are a plurality of such bridles connecting oppositely-disposed areas at the underside of the gunwale so as to engage 4its outer periphery when the weight of the raft is taken by a central overhead shackle through which their respective bights are led, this shackle also receiving a further bridle whose limbs pass through the top of the canopy and are anchored to the raft floor at opposite sides of its minor axis.
To distribute the load, the lower part of each bridle limb may be united to, or reinforced by, mutually-divergent straps whose ends are Separately secured to the raft lloor.
In the accompanying drawings:
FIG. l is a side elevation of one form of the improved raft;
FIG. 2 is an end elevation of the same raft shown suspended from a davit;
FlG. 3 is a plan view of the raft and davit; and
FlG. 4- is a plan view, to a smaller scale, showing the davit in stowed condition.
ln the example illust-rated, the raft (as designed for a complement of 20 to 25 persons) has its gunwale 5 built up in known manner of a plurality of flexible tubular sections joined end-to-end -to -form a single annular chamber which may be subdivided by transverse baffles 6 if desired. Conveniently two such sections are connected together by two assemblies each of (say) four similar, but shorter, sections so that the complete gunwale 5, when fully inflated, outlines an elongated space with parallel sides and half-hexagonal or generally rounded ends.
This space is filled in by two superimposed panels, also of rubberized fabric or similar light impermeable material, which are marginally united to the lower periphery of the gunwale to provide an intlatable watertight floor 7, the internal dimensions of the inflated but unloaded raft being (say) 14 feet long by 8 feet wide.
The basic structure of the raft also includes a central tubular thwart 8 spanning the inner periphery of the gunwale 5 and two vertical tubular arches 9 arranged transversely of the latter adjacent the ends of its side sections. These arches, somewhat smaller in inflated cross-section than the gunwale tube, are built up of adjoined `sections in a similar manner, the lowermost sections of each arch being mutually divergent (at, say, 65 degrees) to meet the gunwale tube somewhat tangentially. The upper parts of the two arches 9 are connected by horizont-al tubes lil at opposite sides of the rafts center-line and at a vertical height of some 2 feet above the gunwale 5.
The arches 9 are situated in spaced-apart relationship and the distance between them is substantially uniform from their points of joinder to the gunwale tube to their upper ends, the arches being maintained in this uniformlyspaced relation by means of the straight and parallel bracing tubes lil. The arches are curved on a continuous line of curvature from one side of the gunwale tube to the other side and they form a storage space when covered by the canopy of a maximum capacity.
The raft is provided in the usual manner with a bottle or bottles 11 of compressed carbon dioxide or other gas, from which the various parts of the basic structure may be inated through the medium of non-return valves 12, further valves 13 being provided for topping-up by means of a manual intlator.
The arches 9 and their connecting tubes 10 collectively support a tlexible canopy 14 comprising outer and inner skins which are marginally united to the gunwale and attached externally and internally of the tubular superstructure so as to 'be spaced apart, for thermal insulation purposes, when the raft is inilated.
A rectangular opening 15 provided in each side of the `canopy 14 between the two arches 9, and with its upper edge deiined by the adjacent connecting tube 10, is closable to any desired extent by means of exible tlaps 16, 17 controllable by tie-tapes 13.
To permit of its suspension from a single cable fall 19, the liferaft is provided with eight bridles 20 of nylon or other webbing, arranged respectively in the longitudinal and transverse central planes of the raft `and at intermediate positions, these bridles all pas-sing through a single shackle 21 above the canopy 14 and having their ends anchored externally of the gunwale 5 and oor 7.
In the convenient arrangement shown, the terminal portions of each bridle 20 are united to, or reinforced by pairs of mutually-divergent webbing straps 22 Whose extremities are cemented for some 6 inches to the underside of the oor 7 at spaced positions around the gunwale 5, being secured to the outer periphery of the latter by means of patches 23.
The eight bridles 20 are wholly external to the canopy 14, but the floor 7 of the raft is -additionally supported from the shackle 21 by a further webbing bridle 24 whose limbs pass through watertight sleeves 25 in the canopy top. The extremities ot this bridle 24 are cemented to the underside of the tloor '7 at short distances fore-andaft of its center, a triangular three-point anchorage being provided in each case by connecting two branch-straps 26 at opposite sides of its center-line.
Assuming that such a raft is initially stowed in known manner within a protective valise or container 27 from which the shackle 21 projects, the rst stage of the launching procedure is to carry such container to the boarding position, adjacent which is mounted a slewing davit 28 of sufficient reach to permit of its fall 19 hanging well clear of the vessels side 29. As shown in FIG. 4, a plurality of the containers 27 may be arranged alongside the guard-rail 39 (a removable or retractable section of which defines the boarding position) so that they can be brought successively rbeneath the outwardly-trained davit 28 and their shackles 21 engaged with its fall hook 31 when the latter is temporarily drawn inboard lby means of a tricing line 32.
While the container 27 is still on deck, bowsing lines 22 connected externally to the raft, and protruding from such container, are made fast to deck cleats 34 at opposite sides of the boarding position and self-inflation of the raft is then initiated in any suitable manner; for example, its gas-release mechanism may be tired by direct manual operation or by tugging a painter line (not shown) whose free end has been made fast on board the vessel.
During this operation, the fall 19 is adjusted so that, by the time the raft has inated, it will be hanging outboard with the top of its gunwale 5 approximately at deck-level and the bowsing lines 33 holding its side tight against that of the vessel, thus allowing passengers to board with a minimum of effort and inconvenience. In this respect the oval planform of the raft is a decided advantage, since the entrance openings 15 in the canopy 14 can be wide enough to admit two persons at a time and of course relative movement of the raft in the plane of the vessels deck can be effectively prevented.
When loading is completed and the bowsing lines 33 cast otl?, the winch 35 of the davit 28 is released to allow the raft to descend under gravity at a safe speed controlled by a centrifugal brake, the fall hook 31 automatically releasing the shackle 21 when (but not until) the raft becomes fully waterborne and being raised by operation of the davit winch 35 (or alternatively a springloaded recovery device) ready for further launchings.
The davit 28, which may be mounted at one side of the boarding position instead of centrally, is conveniently swung inboard and parallel to the vessels side 29 when not in use.
It will be appreciated that, during suspension of the loaded raft, the bracing effect of the tubular thwart 8 and superstructure 9, 10 assist in keeping it in shape, the external bridles 20 serving mainly to resist endwise or lateral tilting of the raft and allowing the bulk of the weight to be taken by the internal lbridle 24 so that such sagging of the floor 7 as does occur tends to urge the occupants of the raft towards their normal seating position adjacent the inner periphery of the gunwale 5.
While the invention has been described hereinbetore with particular reference to the lowering of a loaded liferaft, the improved construction in question will equally facilitate the transference of survivors to any rescue vessel equipped with a suitable davit whose fall can be made fast to the shackle 21 of the liferaft and the latter then hoisted to deck-level instead of its occupants having to make use of scrambling nets lowered over the vessels side.
1. A liferaft comprising, an endless, inflat-able tubular gunwale of oval shape provided with a flexible impermeable i'loor united to the gunwale, two parallel, iuatable, opstanding, spaced-apart tubular curved arches extending on a curved line from one side of the gunwale to its opposite side, two straight, inflatable bracing tubes extending in parallelism from one of the arches to the other and maintaining the arches in their spaced-apart relation and with the distance between them 'being substantially uniform from their points ot joinder to the gunwales to their upper ends, and a flexible canopy marginally united to the gunwale and supported by the inlated arches and their straight bracing tubes.
2. A liferaft according to claim 1, wherein a central tubular thwart extends across the raft at a point centrally of the raft and centrally between the arches, the parallel bracing tubes for the arches being substantially disposed at right angles to the longitudinal axis of the thwart and also at right angles to the longitudinal axes of the arches.
3. A literaft according to claim 1, and including a plurality of suspension bridles respectively connected to oppositely-located areas at the underside of the gunwale and beyond the arches, said suspension bridles being disposed externally of the canopy, `and an additional suspension bridle having limbs extending through the canopy and anchored to the floor of the raft, and a single overhead shackle having parts of the several bridles leading through it, the arches, tubes and thwart collectively bracing the raft against the pull of the bridles when the raft is suspended from the shackle.
References Cited by the Examiner UNITED STATES PATENTS 2,045,587 6/1936 Dean 9 4() 2,970,324 2/1961 Phillips 9-11 3,092,854 6/1963 Manhart 9-11 FOREIGN PATENTS 127,792 6/1948 Australia.
MLTCN BUCHLER, Primm-y Examiner. `FERGUS S. MIDDLETON, Examiner.