U.S. patent application number 12/735272 was filed with the patent office on 2011-06-02 for variable overall hull lengths for watercraft.
Invention is credited to Peter A. Muller.
Application Number | 20110126751 12/735272 |
Document ID | / |
Family ID | 40723185 |
Filed Date | 2011-06-02 |
United States Patent
Application |
20110126751 |
Kind Code |
A1 |
Muller; Peter A. |
June 2, 2011 |
VARIABLE OVERALL HULL LENGTHS FOR WATERCRAFT
Abstract
The invention relates to two parallel added floaters (2) for
watercraft, which are fixed to the stern (1a) on a watercraft hull
(1) or a platform element (31) whereby the single auxiliary bottom
(5) is positioned higher or for the most part positioned higher
than the hull bottom (6) and forms a step. The added floaters (2)
create on the one hand a static lift (As) and on the other hand a
dynamic (Ad) lift. The added floaters (2) or the auxiliary bottoms
(5) can be adjusted independently from each other in trim angle
(N), stroke (H) and deadrise angle (KW) and may have in addition
technical mean (30)
Inventors: |
Muller; Peter A.; (Gattikon,
CH) |
Family ID: |
40723185 |
Appl. No.: |
12/735272 |
Filed: |
December 30, 2008 |
PCT Filed: |
December 30, 2008 |
PCT NO: |
PCT/CH2008/000551 |
371 Date: |
September 28, 2010 |
Current U.S.
Class: |
114/285 ;
114/271; 114/284 |
Current CPC
Class: |
B63B 1/32 20130101; B63B
1/16 20130101; B63B 1/20 20130101; B63B 83/30 20200101; B63B 1/08
20130101; B63B 39/061 20130101; Y02T 70/12 20130101; B63B 2039/065
20130101; Y02T 70/10 20130101 |
Class at
Publication: |
114/285 ;
114/271; 114/284 |
International
Class: |
B63B 1/32 20060101
B63B001/32; B63B 1/08 20060101 B63B001/08; B63B 1/22 20060101
B63B001/22 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 31, 2007 |
CH |
2029/07 |
Claims
1. Added floaters stretching out at the stern of a watercraft
wherein the added floaters form an U and auxiliary bottoms are
positioned higher or at least for the most part higher than a hull
bottom.
2. Added floaters in accordance with claim 1 wherein they have
their origin in front or behind or directly at the stern.
3. Added floaters in accordance with claim 1 wherein the added
floaters are placed in mirror-inverted symmetry and parallel to
each other, behind the engine or placed to each side of an outboard
engine and fixed to the hull.
4. Added floaters in accordance with claim 1 wherein the added
floaters or and the auxiliary bottom show a deadrise angle similar
to the deadrise angle of the hull.
5. Added floaters in accordance with claim 1 wherein the added
floaters create a static lift and a dynamic lift.
6. Added floaters in accordance with claim 1 wherein the dynamic
lift of the added floaters may be different from the dynamic lift
of the hull.
7. Added floaters in accordance with claim 1 wherein the surface of
the dynamic lift of the added floaters is reduced in riding mode,
at the latest in the high speed mode by means of steps in form of
secondary auxiliary bottoms or and phase out angles.
8. Added floaters in accordance with claim 1 wherein the added
floaters or the auxiliary bottoms are trimmable lengthwise to the
watercraft.
9. Added floaters in accordance with claim 1 wherein the added
floaters are adjustable in height by a stroke by means of lifting
mean and cylinders.
10. Added floaters in accordance with claim 1 wherein the deadrise
angles on the added floaters or on the auxiliary bottoms are
adjustable by means of cylinders.
11. Added floaters in accordance with claim 1 wherein the added
floaters or the auxiliary bottoms are adjustable beyond the line of
the hull bottom in the area of the deadrise angles by means of
cylinders and flow means which are fixed to the auxiliary
bottoms.
12. Added floaters in accordance with claim 1 wherein the added
floaters by means of secondary auxiliary bottoms have one or more
generic steps and the auxiliary bottoms and or the secondary
auxiliary bottoms have a standard angle or a phase out angle.
13. Added floaters in accordance with claim 1 wherein the added
floaters have integrated link elements on which the co-bottoms are
dead level to the hull bottom and may form a connection to the
other added floater.
14. Added floaters in accordance with claim 1 wherein the added
floaters are connected to each other by a plate.
15. Added floaters in accordance with claim 1 wherein space is
available between the added floaters for the installation of an
inner floating device.
16. Added floaters in accordance with claim 15 wherein the inner
floating device has a propulsion drive.
17. Added floaters in accordance with claim 15 wherein the added
floaters and or the inner floating device are laminated to the hull
or attached to it as modules and can be of other types of material
from the hull.
18. Added floaters in accordance with claim 1 wherein at the end of
the hull rigid deflectors or by means of cylinders variable
trailing edges are mounted.
19. Added floaters in accordance with claim 1 wherein the left
added floater or the left auxiliary bottom compared to the right
added floater or the right auxiliary bottom can be activated
independently re stroke, trim and deadrise adjustment.
20. Added floaters in accordance with claim 1 wherein the outer
side means and or the inner side means are parallel to the
watercraft axis or tapered at the trailing edge.
21. Added floaters in accordance with claim 1 wherein the added
floaters have technical mean such as trim tabs or and exhaust gas
discharge or and underwater lights or and rudders.
22. Added floaters in accordance with claim 1 wherein the added
floaters are fixed under a platform element.
23. Added floaters in accordance with claim 1 wherein the added
floaters are of different material to the watercraft hull.
Description
TECHNICAL FIELD
[0001] The invention is based on a variable hull length for
watercraft according to the generic name of the first claim.
BACKGROUND OF THE INVENTION
[0002] Watercraft hulls should be able to go through the water with
as little resistance as possible. For this reason, to reduce the
harmful frictional resistance, various auxiliary means have been
introduced, as for eg means which influence the laminar flow, as
described in U.S. Pat. No. 5,819,677 or by reducing the partial
wetted lifting areas on the hull or and by introducing air by
having special air ducts as described in U.S. Pat. No.
5,685,253.
[0003] The not particularly good riding performance at low speed
and during acceleration of gliding hulls can be improved by
additional buoyancy and stability, such as fixing or integrating
extensions onto the hull rear end as described in U.S. Pat. No.
3,783,810. These aids enable the vessel to get quicker to planing
and at the same time reducing trim, which improves the view over
the bow. The same result can also be achieved successfully by
mounting rigid trimtabs.
SUMMARY OF THE INVENTION
[0004] The invention involves that the hull performance of a
watercraft, whether at slow, medium or high speed operation, can be
improved by means of stepped and separated added floaters, which
are fixed at the stern and make specific use of static as well as
of dynamic lifting mean, as well as of the omission of additional
lift, according to the planing conditions.
[0005] The improvement of the hull performance at slow and medium
speed is attributed to comfort, which means to generate best
possible lifting in the stern area, in order to ensure a fuel
saving trim position of the watercraft, as well as a good forward
view especially when changing from displacement to planing speed
and in addition to let the craft softly through the waves. The
improvement of the hull performance at high speeds means that, when
driving at a higher speed, and to achieve fuel saving in comparison
to the total watercraft length this can be achieved by reducing or
by the full loss of contact of the wetted surface at the stern.
[0006] The saying <the longer the better> is correct to a
certain planing speed--called herein riding speed--but afterwards,
friction, which means hull resistance, is hindering more than the
better trim position or the reduced surface pressure of a maximised
surface which means a longer hull. From this point, a smaller hull
surface, which means a shorter hull is advantageous because the
smaller wetted surface of a smaller, respectively shorter hull
generates, due to the increased flow, nevertheless an excellent
buoyancy and lets the watercraft plan more efficiently.
[0007] To enable an improvement of the hull performance for both of
the different driving conditions, as well as for medium mixed
driving conditions, added floaters are fixed or integrated behind
the main engine, respectively at the stern of the watercraft hull
with the bottom surface of the added floaters mounted higher than
the watercraft's bottom so that a step is created. Unlike a
conventional stepped hull which discontinues laminar flow and
forces air under the hull, the additional added floaters have the
primary function to reduce the surface pressure on the hull per
mm.sup.2, as well as due to the improved three dimensional flow, to
influence positively the waves behind the watercraft (fewer waves
equals more efficient drive). Furthermore, with the length of added
floaters a better trimming of the craft can be generated, and at
higher speed from the point on which the additional wetted hull
surface of the added floaters may have a negative effect, by means
of steps which allow the contact to the water flow to be cut off,
therefore the watercraft becomes shorter at the waterline.
[0008] The added floaters are divided, not only to make space for
the stern drives, surface piercing drives, jets or outboards, but
to allow the additional, deliberately limited, bottom surface to
have the best possible effect in the longitudinal direction of the
watercraft so that a best possible trim effect is generated and
also to minimize the purpoising on the lateral axis of the
watercraft when planing, as well as to achieve a better track
keeping and to create an additional lift on the inner far rear
surface of the craft in sharp turns, in order to prevent the
watercraft hull from ditching in this running position.
[0009] As the point on which the additional bottom surface of the
added floater may cause a negative effect (on the grounds of for eg
the load weight and load position within the craft) may vary, an
adjustable stepping of the added floater is of advantage on the
craft hull. This can be controlled by the driver or automatically
by an algorithm.
[0010] In addition the deadrise angle of a V hull has a large
influence on the driving comfort, fuel consumption and the top
speed of a watercraft. Therefore provision has been made for a
variable angle adjustment on the bottom of the additional floater
so that the deadrise of the craft can be adjusted to the driving
condition. The installation of such an adjustable bottom into an
additional fixed or integrated added floater is simpler, compared
to the installation directly into the watercraft hull, as the
unused part of the additional floater can be watertight and hollow
or foamed and is a safe static lifting mean. In addition trim tabs
can be inserted too, further improving trimming as well as the
rolling of the watercraft, whereby this can also be achieved by
adjusting the entire bottom plate.
[0011] The faster a planing craft runs, the more the hydrodynamic
pressure point moves to the rear. A very fast planing craft would
only lie on the lifting bodies and be a very high structural load
for the components. The correspondingly formed or and controlled
lifting bodies prevent the hydrodynamic pressure point from moving
further back but stays constant on one point because of the
intentionally reduced lifting effect of the lifting bodies at
higher speed. All driving conditions refer to measurable and
described conditions like lying at anchor or luring or planing
speed or doing turns. The erratic conditions in heavy seas are not
considered.
[0012] Furthermore the added floaters can be connected to each
other above the waterline and may form a reasonably priced swim
plate or be used as an enlargement of the watercraft's deck.
[0013] As far as the invention is concerned this is dealt with by
the features of the first claim.
[0014] Core of the invention is that by means of additional
floaters, which are placed aft of a watercraft stern and have a
step next to the watercraft hull and can be used as buoyancy
elements to the point as long as the friction of such additional
bottom surface becomes negative.
[0015] When the craft is travelling at increasing speed then the
added floaters lose on purpose the active contact to the damaging
resistance flow, by lifting the hull further out of the water, then
the step generates a clear distance from the water's surface.
Preventing the added floaters from getting into contact with
damaging resistance flow while running at high speed can also be
achieved by a mechanical lifting mean activated manually or by a
control mean. At anchor or at low speed the added floaters generate
static buoyancy.
[0016] Further advantageous advantages of the invention are listed
in the subclaims
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Various exemplary aspects of the invention will be described
with reference to the drawings, wherein
[0018] It shows
[0019] FIG. 1A three dimensional stern view of a watercraft with
two added floaters placed laterally at the stern
[0020] FIG. 2 A schematic sideview of a watercraft hull in three
different driving conditions, a) in displacement- or
semi-displacement mode b) in planing mode c) in speed mode
[0021] FIG. 3 A schematic stern view of a watercraft hull with two
lateral placed added floaters which compared to the stern contour
are placed somewhat elevated and slightly inwards to the stern and
have auxiliary lifting mean
[0022] FIG. 4 A schematic sideview of a watercraft hull with a
slightly elevated rear added floater with added step with an angled
upward edge
[0023] FIG. 5 A schematic sideview of a watercraft hull with a rear
added floater tiltable lengthwise to the vessel and has mean for
pitch control
[0024] FIG. 6 A schematic sideview of a watercraft hull with a rear
added floater which is height variable and has mean for stroke
control
[0025] FIG. 7 A schematic sideview of a watercraft hull with a rear
added floater and therein has an integrated connecting element to
the watercraft stern
[0026] FIG. 8 A schematic stern view of a watercraft hull with two
laterally placed added floaters on which the deadrise can be
varied
[0027] FIG. 9 A schematic stern view of a watercraft hull with two
laterally placed added floaters on which the deadrise can be
altered and has an extendable flow mean attached onto it
[0028] FIG. 10 A three dimensional stern view of a watercraft hull
with two laterally placed added floaters placed on the stern and
attached therein accessories, whereas the added floaters are
connected to each other by means of a plate and in between an inner
floating device with propulsion drives is located
[0029] FIG. 11a,b A schematic floor view of a watercraft hull with
lateral added floaters shown here one-sided which have their
mounting origin in front of or behind the stern
[0030] FIG. 12 A schematic sideview of a watercraft hull with a
rear added floater which is fixed to an overhead platform
element.
[0031] Only essential elements of the invention are schematically
shown to facilitate immediate understanding.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0032] FIG. 1 Shows a three dimensional stern view of a watercraft
hull 1 with two lateral added floaters 2 on the stern 1a, which on
the stern 1a, according to the chain dotted line U, form a U and
having outer side means 3 which run lengthwise or tapered to the
watercraft longitudinal axis, as well as the inner side means 4
which are vertical or have an angle. The auxiliary bottom 5 is
placed higher than the hull bottom 6 whereas the watercraft hull 1
at the stern end has a deflector 7. Finally the added floaters 2
have a transom cover 8 and a cover 9. A closed box form is
advantageous, should the added floaters 2 be foamed, thereby
creating a static lift. Instead of integrating a hull elongation
with a step in the hull 1 thereby generating an additional lift in
the region of the watercraft stern, the required additional space
is divided into two auxiliary bottoms 5, which are in the added
floaters 2 whereby the additional surface has an effect on a longer
longitudinally length measuring unit, should both of the added
floaters 2 have a distance from each other. The larger the distance
of both of the added floaters 2 from each other, the longer is the
auxiliary bottom 5 based on the same surface. Empirical tests have
shown that a length of the auxiliary bottoms 5 in general with
approximately 10% of the hull 1 and a width of 2 times 20% of the
width of the hull 1 have a good value, whereby the explicit goal
for riding in comfort, agility etc. has an influence on the
proportion size.
[0033] The more powerful the engines are and the more they are
fixed in the stern region, the greater is the wish for more dynamic
lifting surface and static lifting volume in the stern region so as
to avoid the hull 1 from submerging and the shorter the watercraft
the more it makes sense to have the added floater 2 as long as
possible so that the watercraft can do it with the least necessary
trim. The additional surfaces 5 offer more buoyancy but the
additional wetted area means more friction. At a certain point the
friction resistance is so important that the previously achieved
better trimming and the low surface pressure per mm.sup.2 is no
more worthwhile, as the flow speed lets the watercraft plan in
total but every additional surface does not add to any additional
lift but only damaging resistance. The goal is, at this point of
flow speed, that flow S on the deflector 7 stalls and the added
floaters 2 are no longer active. By means of this system the hull
1, according to such riding mode, can be lengthened or shortened at
the waterline and create more lift or less friction.
[0034] The function of the outer side means 3 is to lead the
created flow S from the hull 1 with the least possible friction to
the back, and also by intense inclination of the watercraft in
turns, the added floater 2 lying on the innerside in such a turn
achieves buoyancy by means of its outer side mean 3. When riding
straightforward, the inner side mean 4 together with the deadrise
angle of auxiliary bottom 5 helps to further improve the
straightforward stability.
[0035] FIG. 2 Shows a schematic sideview--for better comprehension
the deadrise has been omitted for technical drawing reasons--of a
hull 1 in three different riding conditions, a) in the displacement
or semi displacement condition the hull 1 which is designed as a
gliding hull and having the added floaters 2 still completely
submerged, as well as the hull bottom 6 and auxiliary bottom 5
lying under the waterline WL. The flow S is little and the added
floaters 2 just give more static lift As than dynamic lift Ad. When
in gliding mode b) the hull 1 rides almost on the waterline WL, the
hull bottom 6, as well as the auxiliary bottom 5 lie practically on
the waterline WL, the added floaters 2 only create dynamic lift Ad
and in c) in the speed mode a flow stall takes place on the
deflector 7 and thus the flow S flows horizontally further aft and
eases behind the added floaters 2. So such added floaters 2 do not
achieve additional active lift and as the auxiliary bottom 5 is no
longer actively wetted, there is little or no more friction loss in
that area.
[0036] In this way the hull 1 can be automatically lengthened or
shortened specifically to the waterline WL and focused on the
riding conditions creating more static lift As or dynamic lift Ad
or no lift at all. Therewith the frictional resistance on the added
floaters 2 can be influenced. Not shown, but understandable is that
in heavy seas, should the bow be pointing upwards when going
through a wave, by means of the added floater 2 a counter lift
force can be created with the auxiliary bottom 5, thereby
stabilizing the entire watercraft on the lateral axis as well as on
the longitudinal axis.
[0037] FIG. 3 Shows a schematic stern view of a hull 1 with two
lateral added floaters 2 placed somewhat higher against the stern
contour, which means are stepped and run aft parallel to the hull
1. The outer side parts for example are shifted slightly inwards,
so that the flow S, which originates on hull 1, can flow past to
the outer side means 3 with as little resistance as possible and
these can even be slightly turned up in an appropriate angle so
that these can still create a positive lift even in sharp turns.
The added floaters 2 are firmly fixed as modular elements on the
stern 1a or directly laminated into the hull 1.
[0038] Auxiliary strakes 10 on the inner side parts, only shown in
the drawing on the right side, yield added lifting and are useful
in sharp turns.
[0039] In addition, the stall of flow S at the deflector 7 can be
influenced by a variable trailing edge 11, only shown here on the
left side. This may be varied by cylinder 16, for eg cylinders
which are electrically powered or by fluids and can be operated by
a computerised algorithm or manually.
[0040] From a technical design standpoint the outer side means 3
can also be flush mounted on the hull 1 which is shown in the right
drawing half.
[0041] FIG. 4 Shows a schematic sideview of a hull 1 with a rear,
somewhat elevated stepped added floater 2 and an integrated second
additional step consisting of a secondary auxiliary bottom 12 which
can show a phasing out and upward rise bevel. For better
comprehension the deadrise has been omitted for technical drawing
reasons. Especially in the case of leisure craft a fair valuation
of the center of gravity of the craft is difficult to determine. It
may be that all the passengers on board of a watercraft are at the
rear of the craft and at the same time a tender is attached to the
stern. Therefore it can be advantageous if the added floaters 2 are
correspondingly larger dimensioned for such conditions in order to
generate more static as well as dynamic lift especially when
starting to plan and when in transition to the gliding phase and
thus supporting the hull 1 re trimming. When riding the flow S
creates enough dynamic lift Ad so that the second step with the
secondary auxiliary bottom 12 does not create further active lift,
therefore the friction reduction becomes of greater importance. To
allow a time shifted lift effect, the auxiliary bottom 5 as well as
the secondary auxiliary bottom 12, may be equipped with a phase out
angle Z instead of a horizontal standard angle X. Conceivable are
also multiple steps.
[0042] FIG. 5 Shows a schematic sideview of a hull 1 with a rear
added floater 2 which is trimmable lengthwise to the craft over the
trim angle N. For better comprehension and technical drawing
reasons the deadrise has been omitted. This configuration is
preferable to standard trim tabs 13, which also influence the flow
S and also give a time limited lift. By means of auxiliary bottom 5
much better trimming may be achieved, whereby the trim angle is
much smaller so that a shorter cylinder 16 can be installed in the
added floater 2. The trim is achieved by pivot elements 14 which
are connected to the hull 1 by a mounting bracket 15 and cylinder
16 which can be a fluid cylinder or an electric drive. The trim of
the added floater 2 may be achieved manually or over an algorithm
in controller 17 with corresponding trim sensors 18. Of course
instead of trimming the entire added floater 2, the auxiliary
bottom 5 can only be trimmed.
[0043] FIG. 6 Shows a schematic sideview of a hull 1 with a rear
added floater 2 which is height adjustable. For better
comprehension the deadrise has been omitted for technical drawing
reasons. The problem to calculate the exact point at which the
added floater 2 does not have any added dynamic lift Ad and where
the friction causes overproportional damage, especially with craft
with varying numbers of people aboard, ballast and weight
distribution, the most elegant solution is to be able to vary the
height of the added floater 2 independent of the hull 1
respectively to the hull bottom 6, so that the step, which means
the height difference between hull bottom 6 and auxiliary bottom 5
can be controlled and corrected correspondingly. It is of advantage
if the added floater 2 or the auxiliary bottom 5 is brought up as a
whole, respectively the requested area is lifted up preferably
parallel. Then a one-sided, which means ramp similar lifting, may
lead to a "sticky" effect of the flow at the bottom of the added
floater 2 or auxiliary bottom 5 and therefore does not create the
requested, clear stall at the deflector 7, which shortens the
wetted hull surface rather nicely and hereby reduces the friction
at this point to zero. The lifting is achieved by lifting mean 19,
eg by a screw driven mean or a parallelogram 19a, which is hinged
on one side onto the pivot elements 14 and on the other side at the
added floater 2 on hull 1. The stroke H is achieved by the cylinder
16 which is attached to the parallelogram 19 and is fixed to the
hull 1. The cylinder 16 can be controlled manually or by a
controller 17 which sets the stroke position on stroke H by speed
gauge 20 or rpm gauge and other sensors.
[0044] FIG. 7 Shows a schematic sideview of a hull 1 with a rear
added floater 2. For better comprehension the deadrise has been
omitted for technical drawing reasons. Instead of fixing the added
floater 2 higher, which means stepped onto the hull 1a of the
watercraft, shows first a firm link element 5a on hull 1, whereby
the co-bottom 5b is put on the same level as hull bottom 6 so as to
connect both parts more securely to each other, so that, as for eg
by race events, these can withstand the high forces while wave
jumping. But also shipyards, that modify their watercraft with
regard to the installation or fixation of the added floaters 2, can
also take the opportunity of extending their hull 1 so as to have
an even larger model. This can be accomplished at a reasonable
price by installing the added floater 2, and the link element 5a
also enables a permanent connection to the other added floater 2 on
the opposite side.
[0045] FIG. 8 Shows a schematic sideview of a hull 1 with two
lateral added floaters 2, on which the deadrise can be varied by
means of variable auxiliary bottom 5 which is advantageously fixed
to the pivot point DP and the deadrise angle KW can be modified by
cylinder 16. This function has two aims: on the one hand the degree
of comfort can be set so that the watercraft moves softer through
the waves thanks to a deep V of the added floaters 2, and the craft
uses less fuel. On the other hand the movable auxiliary bottom 5
conveniently replaces the described target in FIG. 6 of friction
reduction from a certain point by withdrawing the area of auxiliary
bottom 5 from the flow S. Instead of lifting the entire added
floater 2, in this technical solution only the deadrise angle KW is
changed so that the flow S does not have any further active contact
with the auxiliary bottom 5. The controlling of cylinder 16 is
achieved exactly as in FIG. 6
[0046] FIG. 9 Shows a schematic stern view of a hull 1 with two
lateral added floaters 2 on which the deadrise can be varied over
the deadrise angle KW to KW1, by means of an auxiliary bottom 5
fixed to the pivot point DP on which a flow mean 23 is attached,
whereby the flow mean 23 can be led over the line of the hull
bottom 6 out into the deadrise angle region KW1.
[0047] The flow mean 23 is a straight or bent plate and functions
as a trim or steering mean. In front of the extended flow mean 23,
in the KW1 area, a flow brake develops, therefore a lifting Ad on
the hull 1 is generated, thereby changing the watercraft's trim
position. Trimming means also steering, thus when lowering the flow
mean 23 on one side, an additional resistance is generated which
moves the watercraft in a turn around the vertical axis, thereby
pushing the craft to a new course or keeping it simply but safely
on track. The settings of the deadrise KW and KW1 is generated by
means identical to those described in FIGS. 6 and 7. Of course,
every deadrise angle adjustment KW and KW1 can also be achieved by
adjusting the added floaters 2.
[0048] FIG. 10 Shows a three dimensional stern view of hull 1 with
two lateral added floaters 2 placed parallel on the stern and the
accessories 13,24,25 fitted therein, for eg. standard trim tabs 13,
exhaust gas discharge 24, underwater light 25, rudder 29 and not
shown here sidethrusters and or small "go home" drives and many
more and are summarized as technical mean 30, whereby the added
floaters 2 are connected to each other by plate 26, which may be
used as a bathing platform or as part of an extended deck.
Furthermore the division of the required additional lifting mean on
the stern into two separate external added floaters 2 can serve so
that the free space between the additional floaters 2 can be used
as an inner floating device 27 which can create limited additional
buoyancy and for eg can be equipped with propulsion drives 28, as
for eg with propeller, jet or paddlewheel so that the engines can
be pushed even further back into the stern area allowing more room
for the persons on board, but at the same time allowing easy
compensation regarding static lift As and dynamic lift Ad by means
of added floaters 2.
[0049] Because of the attachment of the added floaters 2 to the
hull 1 it is also possible to design the added floaters 2 of a
material especially suitable for this stern part which can be
different from the hull 1 and can locally generate more stiffness
and or less weight.
[0050] FIG. 11 a) shows a schematic bottom view of a hull 1 with a
lateral added floater 2 shown from one side which is preferably
fixed to the stern 1a of the hull 1 for technical production and
attachment reasons and thereby has a relevantly greater percentage
influence over the entire wetted area of the hull bottom 6 when
varying the auxiliary bottom's 5 lifting. b) shows a schematic
bottom view of a hull 1 with a lateral added floater 2 shown from
one side which for production relevant reasons, as for eg the
existing molds at the shipyards, which already have lateral
extensions built into their hull bottoms, onto which existing
extensions the added floaters 2 can be directly attached, whereby
the effect of the auxiliary bottom 5 is lower if the watercraft
keeps the same in the entire length as in FIG. 11a.
[0051] Both of the installations have in common that the force
source whether in front of or behind the stern 1a has an influence
on the wetted surface of the entire watercraft as well as on the
static lift.
[0052] FIG. 12 Shows a schematic sideview of a hull 1 with a rear
added floater 2 which is fixed onto an overhead platform element
31. Should there be an existing mold or for weight optimization
reasons, it may be of advantage to leave the hull 1 as it is, and
not to have any material changes but instead to install an adequate
stern platform which is anyway a requested after market product,
which at the same time houses the added floater 2, and so that the
stern form is not affected or and to implement at the same time a
light and firm material for such an additional floater 2. The gap
between hull 1 and added floater 2 can be masked elegantly or shown
as a design element. The platform element 31 can be fixed rigidly
to the stern 1a or used as a lifting platform so that additional
benefits arise from the added floaters 2.
[0053] Of course the invention is not only applicable on shown and
described examples.
DRAWING LIST
[0054] 1 hull [0055] 1a stern [0056] 2 added floater [0057] 3 outer
side mean [0058] 4 inner side mean [0059] 5 auxiliary bottom [0060]
5a link element [0061] 5b co-bottom [0062] 6 hull bottom [0063] 7
deflector [0064] 8 transom cover [0065] 9 cover [0066] 10 auxiliary
strake [0067] 11 variable trailing edge [0068] 12 secondary
auxiliary bottom [0069] 13 standard trimtabs [0070] 14 pivot
element [0071] 15 mounting bracket [0072] 16 cylinder [0073] 17
controller [0074] 18 trim sensor [0075] 19 lifting mean [0076] 19a
parallelogram [0077] 20 speed gauge [0078] 21 rpm gauge [0079] 23
flow mean [0080] 24 exhaust gas discharge [0081] 25 underwater
light [0082] 26 plate [0083] 27 inner floating device [0084] 28
propulsion drive [0085] 29 rudder [0086] 30 technical mean
13,24,25,29 [0087] 31 platform element [0088] WL waterline [0089] S
flow [0090] Ad dynamic lift [0091] As static lift [0092] H stroke
[0093] X standard angle [0094] Z phase out angle [0095] N trim
angle [0096] DP pivot point [0097] KW deadrise angle
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