CA2414545A1

CA2414545A1 - Wave deflecting fender

Info

Publication number: CA2414545A1
Application number: CA 2414545
Authority: CA
Inventors: Herbert D. Klassen
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-01-09
Filing date: 2003-01-09
Publication date: 2004-07-09

Abstract

Wave-deflecting fender positioned across the point of submergence of chines and strakes of a vessel in order to reduce the entrapment of air pockets against said chines and strakes and associated gurgling sounds caused in the entrapment and subsequent escape of said air pockets. The wave-deflecting fender is comprised of an elongated pad (1) made of 1 or more layers of closed-cell foam, and a bridle assembly to affix the position of said pad (1) against a vessel. Said bridle assembly consists of a line aft (2) and an elastic shock chord forward (3) to affix the longitudinal position of the fender, and a lateral shock chord forward (4) and a lateral shock chord aft (5) to affix the transverse position of the fender. An attachment line (6) running the length of said pad adds structural strength to said pad (1) as well as provides loops for attaching said pad (1) with line (2) and shock chords (3), (4), and (5).

Description

-, DESCRIPTION:
Wave-Deflecting Fender For Noise Abatement on Vessels Sleep on board small cruising vessels too often is disrupted by gurgling sounds caused when small waves entrap pockets of air against extreme concavities of a vessel hull such as hard chines ( 1 j and strakes. Apart from use of ear plugs, one current product to abate these noises consists of a floating boom, positioned generally around a vessel.
These booms absorb wave energy and thereby reduce the size of waves inside the boom and corresponding likelihood of air entrapment against the vessel hull.
The wave-deflecting fender improves upon a boom design by physically averting air entrapment at the specific areas where air entrapment normally occurs on a vessel hull.
The wave-deflecting fender is positioned where the vessel hull sharply overhangs the water particularly across the point of submergence of hard chines of vessel hulls, and larger strakes. The fender is secured tightly against a vessel hull by means of a bridle assembly, normally one fender on either side of a vessel. Thus positioned, wave-del7ecting fenders offer approaching waves a smoothly-curved surface with minimized external concavities for air entrapment. Voids between a wave-deflecting fender and a vessel created by concave curvatures of a vessel hull afford further noise abatement by facilitating air passage and averting entrapment of air pockets against a hull.
Figure 1 illustrates intended positioning of a wave-deflecting fender and elements of its bridle assembly relative to a vessel.
The base pad (2j forms the primary element of the wave-deflecting fender. It consists of an elongated sheet of closed-cell foam, usually greater than 4 times as long as it is wide. While a single-layered base pad provides sufficient wave-deflection for most boats, vessels with particularly wide chines may require addition of auxiliary layers of closed-cell foam in order to provide a convex outer surface of the fender and thereby minimize opportunity for air entrapment against a fender or vessel hull. These auxiliary pads (3) are added in a stepwise fashion, staggered inward for each successively lower layer as positioned against a hull (Figure 2).
A wave-deflecting fender includes an attachment line (4) to gain tensile strength, to provide points for attachment for the bridle assembly, and to hold auxiliary pads in position against a base pad. An attachment line threads through perforations in opposite corners of the base pad and is held in place against the base pad by loops tied in either end of the attachment line immediately distal to the perforations, and stop knots tied immediately medial to the perforations (Figure 3). Auxiliary pads likewise are attached to the base pad through threading an attachment line through perforations in auxiliary pads coinciding with those of the base pads, with the stop knots immediately medial to the perforations in t:he most outward auxiliary pad (Figure 2).
A bridle assembly for a wave-deflecting fender consists of a line aft (5) and elastic shock chord forward (6), with their medial ends tied to the respective attachment loops of an attachment line (4j (Figures 1 and 3). Collectively, these fore and aft lines secure the base pad from shifting longitudinally from its intended position. The distal end of the shock chord forward is tied near a vessel's bow. For best results, the shock chord forward is passed under the bow of a vessel and tied on the opposite side of the vessel of the wave-deflecting fender such to provide an inward tension against the hull. The distal end of the aft line is tied near a vessel's stern once the intended position of the wave-deflecting fender is achieved.
Lateral shock chords add lateral stability to the position of a wave deflecting fender and serve to keep the wave deflecting fender pressed against a vessel hull. An aft lateral line (7j attaches to the aft loop of an attachment line (Figure 3), passes under the hull and attaches to the vessel on the opposite side of the vessel and somewhat forward of a wave deflecting fender (Figure i ). A forward lateral line (8) attaches to the forward loop of an attachment line (4) and attaches on the same side of a vessel and somewhat aft of the forward end of a wave deflecting fender (Figure I j.
Cautions:
Note that the desired position of a wave deflecting fender will alter as weight loads in a vessel shift fore and aft, or laterally. 'The ideal position of wave deflecting fenders is such that their longitudinal middle approximately coincides with the point of submergence of a vessel chine when the vessel's load is configured in its night-time position.
Wave deflecting fenders must be detached from a vessel prior to engagement of a vessel engine. Failure to do so may result in fouling vessel propellers with lines from the bridle assembly. Coloured flags (9) warning operators to detach wave deflecting fenders before engine engagement are attached to the distal ends of forward shock chords (Figure 1 ).

Claims

1. A wave-deflecting fender for deflecting waves from entrapping pockets of air under hard chines and strakes of a vessel hull , which comprises of a) a base pad;
b) auxiliary pads;
c) a bridle for affixing the position of said base pad and auxiliary pads against a vessel hull across the point of submergence of chines and strakes.

2. A wave-deflecting fender as described in claim 1 wherein the said base pad is comprised of an elongated strip of closed-cell foam, with an attachment line threaded through perforations at either end of said base pad and affixed in position by attachment loops tied both at the forward end and the aft end of the attachment line against the said perforations distally and stop knots proximally.

3. A wave-deflecting fender as described in claim 1 wherein said auxiliary pads are comprised of a plurality of closed cell foam layers configured to overlap the said base pad described in Claim 2 and each other auxiliary pad progressively staggered medially on successively lower layers as positioned against a vessel hull, with said auxiliary pads affixed to the said base pad by means of a series of perforations coinciding with those in the said base pad and threaded by the said attachment line.

4. A bridle as described in Claim 1 comprising of a line connected to the aft attachment loop described in claim 2 whose distal end is affixed to a vessel in the vicinity of the vessel's stern when the wave-deflecting fender is positioned as described in Claim 1.

5. A bridle as described in Claim 1 comprising of an elastic shock chord connected to the forward attachment loop described in claim 2 whose distal end is affixed to the vessel in the vicinity of the vessel's bow when the wave-deflecting fender is positioned as described in Claim 1.

6. A bridle as described in Claim 1 comprising of a lateral shock chord connected to the aft attachment loop as described in Claim 2 with its distal end passes under a vessel hull and is affixed to the opposite side of the vessel as the said base pad when the wave-deflecting fender is positioned as described in Claim 1.

7. A bridle as described in Claim 1 comprising of a lateral shock chord connected to the forward attachment loop as described in Claim 2 with its distal end affixed a vessel laterally to the said base pad when the wave-deflecting fender is positioned as described in Claim 1.