GB2359523A

GB2359523A - Hull shape for multi hull vessel

Info

Publication number: GB2359523A
Application number: GB0004382A
Authority: GB
Inventors: Anthony Hugh Orr
Original assignee: AWECAT Ltd
Current assignee: AWECAT Ltd
Priority date: 2000-02-25
Filing date: 2000-02-25
Publication date: 2001-08-29
Anticipated expiration: 2020-02-25
Also published as: GB2359523B; GB0004382D0

Abstract

A multi hull vessel has at least two parallel spaced apart water displacing hulls 5,6 each being the minor image of the other and characterised by a divergent bow surface 2 at least on the inwardly facing side of each hull, wherein each hull defines in the stern section thereof an outer 4, a lower 9 and an inner surface 3, the inner surfaces of the respective hulls facing each other and each converging towards said outer surface at the stern section of said vessel to thereby define an outwardly diverging space between said surfaces, with the lower surface of each hull in said stern section extending inwardly beyond the inner surface to thereby define water guide surfaces 10. In cross section throughout the stern part the lower hull surface 9 at least in its outer part is substantially inclined upwardly to meet the outer hull surface 4 at the waterline.

Description

2359523 I The invention relates to a multi hull surface floatation

displacment vessel in which the outer float hulls are asymmetric in their stern part with each hull underwater having considerable aftward taper.

fulti hull vessels of this type havinE two mirror image float hulls that are asymmetric in their stern part (aftward of the widest waierline beam) and arranged with their fore and aft axes parallel and their outer hull surfaces parellel with each null comerising in the siren pars an outer inner and lower surface. The lower surface when viewed in elevation is parallel ic the wazerline, and in cross section generally horizontal, the inner surface converges aftwardly tcwprds the said outer and or lower surface so produce an outwardly and aftwardly opening space between she two hulls, with the lower surface of each hull in the stern pars extending inwardly beyond the inner surface to define a water Euide surface.

in rough seas pitching will cause the vessel described that has a relatively large ratio of horizontal to vertical hull surfaces to nound she seas surface on each downsiroke of pitching.Crew iiscomfort leading qiuckly to 7oss of efficiency ana poor decision nakinE normally result from sustained exposure to this severe motion.

7he invention relates to all types of multi hull vessels although she following description refers to a catamaran it is equally applicable to integrated catamarans and trimarans.

---l- The rurDose of this invention is to produce a more seaworthy multi hull vessel. The configuration of this new vessel will reduce the impact loads experienced by the hull's lower surface when pitching, thereby permitting a reduction in the construction materials without endanger,!-ng the structural in-,egrity of -'L-,he vessel.

Accordinz to the present invention there is provided a surface floatation marine vessel of multi 'null con'igura-.:on in which a bridginp, means connects at least -wo identical but mirror image nulls exl-,i-oi-Lir-g considerable aftward taDer in their respective underwater stern)p.ris each hU-K being symmetrically arrar---ed about the vessels fore and aft axis and -'s asy-.-mez--ic in each stern mart that is outward facing, with the float ?lulls being spaced apart parallel z3 each other and Darallel to the vessels fore and a,'7'-, axis, each hull having a iivere:ent bow surface on,the outward &inward facing side surface and wherein each hull:defines in its stern part aftward of the widest waterline beam) an outer!owe-- and inner surlace,zhe outei:Dy (definition that aftward of midships above the waterline) continues aftwardly without significant convergence to the huhhls fore and aft axis adjacent to the. vaterline,, and is characterised that in cross section hrou,-,,hcut th-e stern mart the lower hull surface at least in its outer mart is substantially inclined uowardly outward to meet the said outer bull surface at the waterline and continue aftwardly in this configuration to the athwartships plane that cuts the end of the waterline such that L.1 elevation the lower hull surface or an aftward extension of that surface does not significantly converge aftwardly uD rd to the waterline, -wa the inner bull surface aftward of -nidsh.iDs at!east beneath the waterline converges towards the afore said outer surface and or lower surface, to thereby define an outwardly and aftwardly diverging space between the vessels two inner hull surfaces, with the lower surface of each hull in the stern part extending inwardly beyond the inner surface to thereby define a wpter guide surface.

_s a ni,.nn view of a -iulti hulled vessel of 2aua--iaran type ennstruc-, ed using zwo mirror -i.ria,-e hulls with a bridging means.

2 s an examDle of an ir.-eg--a-ed and bridge configuration in which the bridge is situated above the water at least immediately L -L adjacent to the inner surface of each 'inull,where each Inull is a mirror J 4-Tia,ge of -.he ozher.

7,z. j shows the iulls in Fig. 1 and Fig. 2_ in elevation,together with a range of iocations for above and below waterline chines. 1 F i g - show various configuratiOns of the hull in cross section at the -fovward cornmencement of the stern Dart-here in after terr.ied the midship cross section.

Fig. corrispond to the -iidshirs cross section configurations shown in Fig. -/4-/6 with cross sectienal views for each of the 6 aforesaid configurations at locations indicated in Fig. as at C-C 1 ID - r- E - z.

Tefering to 'Fig. aran constructed using two mirror / shows a catam image hulls -5- and 6 placed apart having a bridging means with divergent bows 21 on both outer!4nd inner hull surface nd _In the stern part an outer hull surface by definition is that hull surface in the stern Dart above the waterline 11 and in plan dees not significantly converge aftwardly towards the hulls -fore and aft axis.

The inner h:ull surface _n the stern -art does --nverc-e towards -,ne 3 =ter hull Surface, and 3r -,onver-e to the lower hull sur-.Face U si-ow.1-4e three sai- 1 surfaces or its wa-.erpa-de ?. and da7erg-,uide 4? Z'---er.minaze -r the >-d--,t most afr.wardly commences o--wardly as an af-ward continuation of the midships cross section configuration and viewed --'n cr-ss section ex-ends IFrom, the waterline on the outer surface with t-he lower Surface Cr to extend inwardly across the hull to the inner surfacq such that this position is,or equal to, the lowermost A-e)th below -,lie waterlline of the lower surface - The lower surface is characterised -hat when viewed Ln cross section at least a substantial 7art of -,he outer uart is inclined upwardly outward as shown in Fig.4-6-, q /0 -121-14-16 2-6 and does not in Dian at any level below --7e waterline converge aftwardly with the Inulls -fore and aft axis, and that in elevation does not converge afiwardly -arward to the waterline, such that at- the intersection of the said iower surface in any vertical plane parallel to the fore and aft axis either cuzward or inward from it is narallel So -,he waterline.

1 S t Fig. T-7- 23-.Z-S--2.7 and Fig.

show the waterguideIR to be the aftward extension of the lower hull surface j that extends to the stern when viewed in elevation, its upper surface being an inward extension of the said inner surface _3 and its lower surface an inward extension of the said lower surface ? che inner edge of the waterguide being parallel to the vessels fore and aft axis and in alignment with its edge at midships. Fig. 11 and Fig. Ill. 711- 11show an additional waterguide.10 that is an inward extension of the aforesaid waterguide j? or an inward extension ef ihe lower surface where no waterguide was Present and that the additional waierguide lo when viewed in cress section is horizontal as shown in Kg. and in elevation is horizontal, and that in cross section is extends inwardly beyond the vertical fore and aft plane that cuts the dazumn wazerline at midshins.

Fig.,Z. shows the integrated hull and bridge configuration using two identical mirror image float hulls with a bridge structure suitably shaped above the waterline throughout the float hull's stern part to ensure wave clearance of the underside of the bridge and thereby also allowing free access for air to the float hull's stern part.

Tn a further embodiment the vessel may be of TRImaran configuration where the two outer hulls are identical mirror Image float hulls according to the invention with the third hull located midway between the two said float hulls.

L.n general the lower hull surface m 9 r. ay be singularly planar as shown or multi planar as shown in Pig.

in iR. 5--7 7-1 2_ 1- 2-5- 2_ Alternatively the outer and lower surfaces 44 2 4? as shown in 7-ig. may be arctuate as indicat-ed by the dashed lines in each cross sec-.1-,,n --ou s h o wn. curvature running zhreu,,.-, the stern -jart. Where -he hull surfaces 3-4-< shown in 'Fig.

1 7-A"-2 0 -21- 2 2 -213Z-4 as angular Junctions between -=;d-jacent surfaces, or between --wo cr more cc.-rwnenzs comprising C.n. e '-.u-: I surf ace, --'-ese jur. cz ions -nay be curved. ihere the lower surface cemprises more than one p-lana-- surface, the junction between -.!7ese 7ar-,s will lie Darallel wiih the hulls --"ore and aft axis viewed in nian. ----houRh -,"--e outer 'null surface is considered to be Renerally upright in its upper part, it may as shown in =enerally u-Dr-4Fn-L - - tl 'ts -.cwer Dart Lt is inclined downwardly inward where it remains n i - -)aral-.el zo the hulls fore and aft 'iriher the cuter hull surface + t.iay be inclined eit-her upwardly outward or upwardly inward Droviding ha zhe lower part of -,his sufface conforms to the requirement of being parallel -,c the hulls _fore and aft axis when viewed in Dlan at any horizontal above the waterline.

he 1-1exible -naterial of the ---!oat hulls nay be constructed off inflated is application -,he waterguidesg and 0 Y.P e c ommon in marine,se. Ln -uh-L t, should be of ri--id construction mc ensure continuity of shape. This last feature is equally J.-npcriant in the construction of the waterguides in all aDDlications.

Claims

CLAIM, A surface floatation marine vessel of r multi bull configuration in

wnicn a bridging- means connects at least two identical but mirror image hulls exhibiting considerable aftward taper Jn their res- rective S underwater stern parts each hull being symmetrically arranged-about the ves e's fore and aft axis and is asymmetric in each stern part that is outward the fIcat hulls being spaced apart parallel to each other and narallel to -he vessels fore and aft axis,each hull having a d-'ivergen+. bow C surface on tbe outer and inner facing side surface 5ind wherein each hull -1e- n -.s stern nart aftward of 'he widest waterline beam an outer 'ine s i 'ion 'hat ftward lower and an inner surface, the outer surface ( by defJni-,. 1 of midships above the wamerline.1 continues aftwardly -,,ii+.houT, s i gn i f_L an t converzence -,o the hulls fore and aft axis adjacent to the waterline, and is characterised that in cross section throughout the Dart the lower hull surface a-,. least in its outer Dart is substantially inclined upwardly outward to meet the said outer hull surface at -he waterline and continue aftwardly in this configuration to the athwartshiDS Dlane that cuts the end of the waterline such that in elevation the lower gnificently null surface er an aftward extension of that surface does not si converge aftwardly upward to the waterline, the inner hull surface in. the stern Dart at least beneath the waterline converges towards the a. Lorv -aid outer surface and or lower surface, to t-'.-,ereby define an outwardly and af-t-w2rdly diverging space between the vessels two inner hull surfaces, with --he lower hull surface of each hull in the stern nart extending inwardly beyond the inner surface to thereby define a sater guide surface.

13 CLAIM 2. A multi hull vessel as claimed in claim I. in which the aftward extension of the said lower hull surface is by means of a waterguide that extends to the stern when viewed in elevation its upper surface being an inward extension of The said inner hull surface and its lower surface being an inward extension of the said lower hull surface, the inner edoe of the waterguide being. -parallel to the vessels fore and aft axis and in llonffitudinal alignment with the inner edge of the bulls lower surface at midshims.

i CL A I M 35 A multi '-u--,-- vc-sse'L as ---',a.-Lmed in claim 1 and 2 -n which an additional water,-uide -hat 4s an inward extension of Ihe waterguide in clai-m 2 or an inward extension of -.he huils lower surface.,;nere no wat-erguide is nresent -.bat when viewed in cross section and elevation is horizontal and that in cross secticn extends -Inwardly beyond -the vertical fore and aft Dlane that cuts zhe waterline at midshiDS.

CLALY 4. A. multi hull vessel as claimed in claim I through claim 3 in which a water displacing divergent bow surface is present on both inward and outward facing bow surfaces.

CLALM 5. A multi hull vessel as claimed in claim I through claim 4 n which the outer hull surface in the stern Dart is generally upright in its upper part and in its lower Dart above the waterline inclined downwardly inward when viewed in cross section.

q CLAIM 6. A multi hull vessel as claimed in claim I through claim 5 in which the said lower hull surface may be inclined upwardly outward across the entire width of the lower surface when viewed in cross section.

CLALY. 7. A multi hull vessel as claimed in claim I through claim 5 in which the said lower hull surface inward of that part inclined upwardly nutward be generally horizontal when viewed in cross section.

CLAIM 8. A mulzi hull vessel as claimed in claim I through claim 6 or claim 7 where in cross section the said hull surfaces outer lower and inner and waierguide as in claim 2 and claim 3 are defined by straight lines.

CLA-U 9. A multi hull vessel as claimed in claim 8 wherein the junctions between the said outer and lower hull surfaces is curved.

CLALM. 10. A multi hull vessel as claimed in claim I throug ugh claim 7 that when viewed in cross section has the said outer lower and inner hull surfaces together with she waterguide as claimed in claim 2 defined by curved lines.

CATIAIM II. A multi bull vessel as claimed in claim I through 7,9 and 10 claim X be TRImaran form in which a central hull is located centrally between Me two outer hulls as essentially described in the aforesaid claims.