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An Experimental Study on the Relative Motions Between a Floating Harbour Transhipper and a Feeder Vessel in Regular Waves

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The Floating Harbour Transhipper (FHT) is a pioneering logistics solution that was designed to meet the growing demands for coastal transhipment in the mining sector as well as commercial port operations. The primary advantage of the FHT system is that it can reduce transhipment delays caused by inclement weather, by reducing relative motions between the FHT and feeder vessel. The feeder is sheltered when inside the FHT well dock when compared to the more exposed location when a feeder is in a traditional side-by-side mooring arrangement. This paper discusses previously published studies into the relative motions of vessels engaged in side-by-side mooring arrangements and also presents details and results from a series of physical scale model experiments. In these experiments, both side-by-side and aft well dock mooring arrangements are investigated. The results provide strong evidence that the FHT well dock concept can significantly reduce the heave, pitch and roll motions of feeder vessels when transhipping in open seas - this being the cornerstone of any successful open water transhipment operation.
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Trans RINA, Vol 154, Part A2, Intl J Maritime Eng, Apr-Jun 2012
©2012: The Royal Institution of Naval Architects A-97
TECHNICAL NOTE
AN EXPERIMENTAL STUDY ON THE RELATIVE MOTIONS BETWEEN A FLOATING
HARBOUR TRANSHIPPER AND A FEEDER VESSEL IN REGULAR WAVES
(DOI No: 10.3940/rina.ijme.2012.a2.228tn)
G J Macfarlane and T Lilienthal, Australian Maritime College, University of Tasmania, Australia
R J Ballantyne and S Ballantyne, Sea Transport Corporation, Australia
SUMMARY
The Floating Harbour Transhipper (FHT) is a pioneering logistics solution that was designed to meet the growing
demands for coastal transhipment in the mining sector as well as commercial port operations. The primary advantage of
the FHT system is that it can reduce transhipment delays caused by inclement weather, by reducing relative motions
between the FHT and feeder vessel. The feeder is sheltered when inside the FHT well dock when compared to the more
exposed location when a feeder is in a traditional side-by-side mooring arrangement.
This paper discusses previously published studies into the relative motions of vessels engaged in side-by-side mooring
arrangements and also presents details and results from a series of physical scale model experiments. In these
experiments, both side-by-side and aft well dock mooring arrangements are investigated. The results provide strong
evidence that the FHT well dock concept can significantly reduce the heave, pitch and roll motions of feeder vessels
when transhipping in open seas – this being the cornerstone of any successful open water transhipment operation.
1. INTRODUCTION
Bulk ore product is usually shipped directly from shore
facilities using large bulk carriers (typically either
Panamax or Capesize ships) which require large,
expensive port facilities, often involving dredging
operations and the need for visually obtrusive shore
storage sheds (for example, possessing a capacity of
80,000 tonne for a Panamax load). Substantial reductions
in capital and operating expenditure are achievable by
relocating the major stockpile to an offshore floating
facility (mothership), thus requiring a much smaller
shore facility (around 10,000 tonne capacity). The
product is transferred from the shore facility, which can
be located within a small harbour, to the mothership via
two or more shallow draught feeder vessels.
The transhipping objective for defence and disaster
response and mining is the same, which is to transfer
large volumes of cargo with minimal time and costs into
remote areas with little or no infrastructure in all types of
weather.
This technical paper reviews a case study on the
development of the Floating Harbour Transhipper (FHT);
a novel design that can not only increase export and
import capabilities, but also strengthen emergency
response and military capabilities. For a relatively simple
modification for defence use, the FHT can provide a
large percentage of the military requirements for a small
fraction of the cost.
2. THE FLOATING HARBOUR
TRANSHIPPER (FHT) CONCEPT
Traditionally, the transfer of bulk ore cargo from a feeder
vessel to a moored ‘mother’ ship is conducted with the
feeder vessel moored side-by-side to the mothership. The
FHT concept adopts a novel alternative, where the feeder
vessel is moored inside an aft well dock in the
FHT/mothership. The FHT is a covered floating storage
vessel which incorporates a wet dock facility at the aft
end to suit the feeder vessels. It also has its own bulk
cargo handling equipment, not just for the transfer of
material from the feeder vessel into its own stockpile, but
also from this stockpile to an export ocean going vessel
moored alongside. This system eliminates grab spillage
and dust, common to other transhippers.
The concept is depicted in Figure 1, where a feeder
vessel of up to 10,000 dwt capacity is moored inside the
stern well dock of a Capesize capacity FHT (100,000 dwt
capacity). An export vessel (in the foreground) is moored
alongside the FHT. In this figure, the feeder vessel is
partially obscured by the covered deck of the FHT. For
this example, the feeder vessel is a Stern Landing Vessel
(SLV), as described by Ballantyne and Ballantyne (2007)
and is carrying bulk ore product for mining transhipment
options, as depicted in Figure 2.
The FHT concept provides an environmentally and
operationally compelling solution that can provide
significant advantages for the country, community and
mining companies. The key advantages for the FHT and
SLV feeder system relevant to mining operations are
summarised as follows:
Trans RINA, Vol 154, Part A2, Intl J Maritime Eng, Apr-Jun 2012
A-98 ©2012: The Royal Institution of Naval Architects
The stockpile is at the export site, downsizing or
eliminating the need for large expensive
negative pressure sheds ashore and large wharf
facilities;
Provides dust-free transhipment, eliminating
issues close to residential areas;
Can handle rougher seas, therefore eliminates
demurrage;
Shallower draught feeder vessels can be used
from very small ports or unprepared beaches at
scheduled times, eliminating the need for
dredging of sensitive areas;
A small shallow harbour eliminates the cost of a
major jetty structure and the bond for its
removal at end of the mine life;
Upon completion of the mine life, a small
harbour is available for the community or
traditional owners;
Revenues from mining royalties can be secured
at an earlier timeframe;
Reduces the need for road transport (and
associated greenhouse gases) by using small
harbours closer to the mine site;
Provides employment and training opportunities
in feeder vessel operations;
Reduces capital expenditure and sovereign risk;
Operating expenditure can be reduced due to
lower power and manning requirements when
compared to more traditional systems;
Port charges, such as berthage, wharfage and
tugs, can be reduced;
The FHT well dock arrangement eliminates
stevedoring damage to feeder and transhipment
vessels;
An FHT with SLV feeder vessels can handle
inbound fuel and other dangerous goods (such
as ammonium nitrate) and outsized heavy lifts
into areas with little or no infrastructure;
A feeder vessel can be secured within the well
dock bow first to push the FHT to redeploy to
disaster sites, cyclone moorings or dry dock;
The FHT requires minimal manning (4-6 crew);
The FHT has no propulsion engines or large
superstructure and incorporates anchor ground
tackle to suit the combination of the FHT and
export vessel.
The FHT can use stern transverse thrusters to
avoid beam sea conditions.
It is acknowledged that typical Landing Helicopter Dock
(LHD) ships, such as the Canberra Class selected for the
Royal Australian Navy (Semaphore, 2007), incorporate a
similar stern door access for loading smaller vessels.
However the FHT system is unique in the sense it is a
permanently open aft wet dock which is not restricted to
small craft only. The wet dock in this instance has been
designed to reduce surge, sway and yaw effects and
dampen roll, pitch and heave motions of the feeder
vessel.
The primary advantage of the FHT system is that it can
dramatically reduce transhipment delays caused by
inclement weather, by greatly reducing relative motions
between the FHT and feeder vessel. The feeder is
significantly sheltered when inside the FHT well dock
when compared to the more exposed location when a
feeder is in a traditional side-by-side mooring
arrangement. For example, it is common for alongside
transhipment operations to typically be limited to
significant wave heights of up to approximately 2.5
metres which can be seen in many operations currently in
the market. Preliminary investigations indicate that
feeder vessel operations can be handled, uninterrupted, in
seas of up to 5 metres for the FHT concept. The main
purpose of this paper is to present some of the results
from a series of physical model experiments which were
conducted to investigate this specific issue.
3. LITERATURE REVIEW
To the authors’ knowledge, there are no publicly
available studies that have investigated the relative
motions of two vessels, of similar relative sizes as
proposed in the FHT concept, where the smaller vessel is
moored inside an aft well dock. There exist several
published studies that have investigated the relative
motions of two vessels in a side-by-side arrangement,
with most studies dealing with the application of
numerical codes to this problem, and their efforts to
validate predictions by undertaking a comparison against
limited scale model experimental data. For example, see
Kodan (1984), Buchner et al. (2001), Fang and Chen
(2001), Inoue and Ali (2003), Kim et al. (2003), Hong et
al. (2004), Lewandowski and Naud (2004), Koo and Kim
(2006), Huijsmans et al. (2007) and Xiang et al. (2007).
It is important to note that there are some significant
differences in the relative lengths of the two vessels
compared to our current study. For example, the ratio of
feeder length to mothership length ranges from
approximately 48% up to 93% of the proposed SLV/FHT
concept under consideration here. As might be expected,
the range of vessel displacements also vary considerably
which makes direct comparison of the published
numerical and experimental data with the results from
the present study a more complicated task, and possibly
of limited value.
When two vessels are moored side-by-side, it is expected
that the motion of both vessels will be affected by the
presence of the other vessel, both through the mooring
system and from hydrodynamic interaction. Thus, it is
inappropriate to assume that the motions of any single
vessel in a known seaway will be the same as the case
when that vessel is alongside any other vessel. In
addition, the manner in which the vessels are connected
and moored can have a significant effect on the resultant
motions. This is one of the reasons why validation of
numerical predictions, usually through the conduct of
physical scale model experiments, is so important in such
cases. One common general trend found from the
Trans RINA, Vol 154, Part A2, Intl J Maritime Eng, Apr-Jun 2012
©2012: The Royal Institution of Naval Architects A-99
published studies is that the smaller (feeder) vessels
experience notably greater motions than the larger vessel
(mothership).
Both Hong et al. (2002) and van der Valk and Watson
(2005) investigated the forces and motions of both side-
by-side and tandem vessel arrangements (where one
vessel is aft the other) through the conduct of physical
scale model experiments. A similar study using a higher-
order boundary element method was conducted by Choi
and Hong (2002). Each of these studies indicate that the
aft positioned vessel has lesser motions due to the
shadow effect of the windward vessel. The tandem
position is not under consideration in the present study as
it is generally used for the transfer of liquid products, not
solid materials.
Recent work by some of the present authors has involved
the measurement of the motions of a landing craft within
a flooded well dock while in a seaway, however in this
work the size of the well dock is considerably larger than
the vessel inside it, Cartwright et al. (2007). This work is
primarily related to military applications and
unfortunately very little is presently available in the
public domain. But the process of undertaking such
experiments has been of considerable benefit in the
development of suitable techniques and procedures for
undertaking such work, which has been utilised in the
present study.
4. EXPERIMENTATION
The model experiments were carried out in the shallow
water wave basin at the Australian Maritime College in
Launceston, Tasmania. The water depth in the basin was
simulated to represent a typical coastal region having a
constant depth of 15 metres. A variety of incident wave
conditions and vessel headings were investigated as part
of a comprehensive test program. Experimental results
presented within this paper concentrate on a series of
head sea tests in regular sinusoidal waves having
nominal wave heights corresponding to 2m, 4.5m and
7.7m. A wide range of typical wave periods were
investigated.
The primary particulars of the FHT and feeder vessel, in
both model (scale 1:44) and full scale, are provided in
Table 1. Results presented here are for the case with the
FHT in ballast condition and the feeder vessel at half
load condition. These lighter conditions were
investigated to simulate a common worst case scenario.
Full displacement conditions in general produce smaller
motions; hence it is common practice for ships to ballast
down during storm conditions.
The motions of both vessels were measured using a non-
contact optical tracking system based on infrared
cameras (supplied by Qualisys). Two specific cases were
investigated; (a) with the feeder vessel alongside the
FHT and; (b) with the feeder vessel located inside the
well dock of the FHT.
For the study with the feeder alongside the FHT, the
feeder was located on the portside of the FHT with the
longitudinal location defined by lining up the midships of
both vessels and the bows orientated in the same
direction, as can be seen in the photograph shown in
Figure 3. The starboard side of the feeder model was
attached to the port side of the FHT model using a pair of
vertical slides and universal joints, refer Figure 4. The aft
vertical slide/universal joint also incorporated a short
horizontal slide. This arrangement allowed freedom in
heave, pitch and roll, whilst constraining the feeder
model in surge, sway and yaw (relative to the FHT
model).
In the case where the feeder was located within the well
dock, the stern of the feeder model was attached to the
internal end wall of the FHT well dock using a vertical
slide and universal joint and the bows facing opposite
directions. This allowed freedom in heave, pitch, roll and
yaw, whilst constraining the feeder model in surge and
sway (relative to the FHT model). The photograph in
Figure 5 provides a general view of this set up. Fenders
were attached to the inside walls of the FHT well dock
near the entrance to limit the yaw movement of the
feeder.
A simplified mooring system was adopted to ensure that
the FHT model maintained the required nominal heading
to the incident waves. This mooring system included a
pair of mooring lines, one each from the bow and stern of
the FHT model (connected at the still waterline). The
stern mooring line incorporated a bridle so as to avoid
contact with the feeder model.
It is acknowledged that there would be value to also
assess the mooring and restraining loads, however the
primary focus of these initial physical experiments was
on proof of concept through an evaluation of the relative
motions of the two craft. An assessment of these loads is
planned as part of further research into this concept.
5. RESULTS AND DISCUSSION
A comparison of the resultant heave, pitch and roll
motions for an incident wave height of 2 metres at a
heading of 180 degrees (head seas) is shown in Figures 6,
7 and 8 respectively. A range of wave periods from 4 to
12 seconds were investigated with both the feeder inside
the FHT well dock and the feeder alongside the FHT.
As can be seen in Figure 6, the heave motion (at the
LCG) of the FHT did not vary appreciably between the
cases when the feeder vessel was located alongside or
inside the well dock. In contrast to this, the heave
motions of the feeder are significantly greater when it is
Trans RINA, Vol 154, Part A2, Intl J Maritime Eng, Apr-Jun 2012
A-100 ©2012: The Royal Institution of Naval Architects
alongside the FHT compared to when it is located inside
the FHT well dock.
The pitch motions of the FHT did not vary appreciably
between the cases when the feeder vessel was located
alongside the FHT or inside the well dock (refer Figure
7). Interestingly, the pitch motions of the feeder vessel
are quite similar to that of the FHT while it was located
inside the well dock, with typical maximum values
around 0.4 to 0.5 degrees. However, when the feeder was
located alongside the FHT its pitch motions became
significantly larger, by almost an order of magnitude,
with the peak value approaching 4 degrees. In each case,
the peak pitch angles occur at incident wave periods in
the region of about 10s to 11s.
As might be expected, the roll motions of the FHT were
generally relatively small for head sea conditions, as
shown in Figure 8. However, in wave periods greater
than 8 seconds, the FHT rolls more when the feeder is
moored alongside than when it is inside the well dock,
suggesting that the presence of the feeder alongside
adversely affects the motions of the FHT. The roll
motions of the feeder vessel whilst inside the well dock
is similar to the roll motions of the FHT, but considered
to be relatively small with values generally less than 0.2
degrees at all wave periods investigated. Of significant
concern are the notable roll motions of the feeder vessel
when moored alongside, which are found to exceed 3
degrees (around a wave period of 9s) which, similar to
the pitch motions, is around an order of magnitude
greater than found when the feeder is located inside the
well dock.
In summary, the results presented in Figures 6, 7 and 8
highlight the potential reduction in heave, pitch and roll
motions that can be achieved by ‘sheltering’ the feeder
vessel within the aft well dock of an FHT. It is
acknowledged that the motions of the feeder vessel when
alongside the FHT could be controlled (reduced or
potentially increased?) to some extent by the manner in
which it is moored to the FHT, however, in certain
circumstances this may be impractical.
Further experiments were conducted in head seas at
greater nominal incident wave heights (up to 7.7 m) in
order to determine the effect this has on the motions of
both the FHT and feeder vessel. Cross-plots of the
motions as a function of increasing wave height are
provided in Figures 9, 10 and 11 for the nominal full
scale wave period of 10s. This wave period was selected
as the maximum motions were found to occur at or close
to this wave period in the results presented in Figures 6,
7 and 8. It should be noted that tests on the case with the
feeder vessel alongside the FHT were limited to incident
waves of approximately 4.3m in height due to
unacceptably high motions at higher wave heights.
The heave motion of the feeder when located alongside
the FHT is approximately twice that of the feeder when
located inside the FHT well dock at the nominal wave
heights of 2.0 and 4.3 metres, as can be seen in Figure 9.
It appears that the heave motion for both the FHT and
feeder are, in general, increasing linearly with increasing
incident wave height, which agrees with linear ship
motion theory, Lloyd (1998).
The pitch motions of the FHT and the feeder vessel,
when located inside the FHT well dock, are very similar
over the entire range of wave heights investigated
(Figure 10). However, when the feeder was located
alongside the FHT the pitch motions are approximately
eight times higher than case with the feeder located
inside the FHT well dock. The pitch motions of the FHT
and feeder (when inside the well dock) can be seen to
follow a general trend of increasing magnitude relative to
the increasing incident wave height, i.e. a linear
relationship exists, as was found for the heave motions.
Relatively small roll angles (<1 degree) were
experienced by the feeder vessel when located inside the
FHT well dock at all three wave heights (Figure 11). In
contrast, when the feeder was located alongside the FHT
the roll angles were found to exceed six times this level.
The roll motions of the FHT were marginally greater
when the feeder was side-by-side the FHT than inside the
FHT well dock.
Both the rotational motions (pitch and roll) of the feeder
vessel when moored inside the well dock are
significantly less at all incident waves heights
investigated (2.0m, 4.3m and 7.7m) than those measured
at just 2.0m high incident waves for the alongside case.
As previously mentioned, it may be possible to utilise
alternative mooring arrangements to reduce the alongside
motions, however, there will be a practical limit as to
how effective and safe this will be.
Further analysis of the experimental data is presently
underway to investigate the relative heave motions at
other critical locations of both vessels and different wave
headings, as are investigations of the practicality of
implementing a more substantial system to moor the
feeder vessel within the well dock to further reduce the
motions. It is also planned to conduct additional
experiments in various irregular seaways.
6. CONCLUDING REMARKS
The concept of a Floating Harbour Transhipper (FHT)
for transferring bulk cargo offshore in open seas is
outlined and discussed, including the use of smaller
shallow-draught feeder vessels to transport bulk goods
and equipment from small harbours or unprepared
beaches to the FHT. A novel aspect of the FHT is the aft
well dock in which the feeder vessels are moored during
the transfer operation, thus taking advantage of the
benefits of being sheltered from incident waves.
Trans RINA, Vol 154, Part A2, Intl J Maritime Eng, Apr-Jun 2012
©2012: The Royal Institution of Naval Architects A-101
A series of physical scale model experiments were
conducted to investigate the differences in relative
motions of the feeder vessel when moored inside the
FHT well dock compared to a more conventional side-
by-side mooring arrangement. The well dock
configuration was found to significantly reduce the
motions of the feeder vessel. In some cases, such as with
pitch and roll, the motions of the feeder vessel were
reduced by an order of magnitude by locating the feeder
inside the aft well dock. It was also found that both the
pitch and roll motions of the feeder, when moored inside
the FHT well dock, were very similar to the motions of
the FHT itself.
7. ACKNOWLEDGEMENTS
The authors thank Albert Sedlmeyer and James Keegan
at Sea Transport Corporation and Peter Tomic, Kirk
Meyer and Liam Honeychurch of AMC for their
invaluable assistance on this project.
8. REFERENCES
1. Ballantyne, S. and Ballantyne, R., ‘Stern
Landing Vessels’, Proceedings of the RINA
International Conference on Military Support
Ships, London, UK, 2007.
2. Buchner, B., van Diij, A. and de Wilde, J.,
‘Numerical Multiple Body Simulations of Side
by Side Mooring to an FPSO’, Proceedings of
the 11th International Offshore and Polar
Engineering Conference, Stavanger, Norway,
pp 343 – 353, 2001.
3. Cartwright, B., Renilson, M.R., Macfarlane,
G.J., McGuckin, D. and Cannon, S., ‘Motions of
a Landing Craft in a Flooded Well Dock –
Effect of Well Dock Design’, Proceedings of
the RINA International Conference on Military
Support Ships, London, UK, 2007.
4. Choi, Y.R. and Hong, S.Y, ‘An Analysis of
Hydrodynamic Interaction of Floating Multi-
body using Higher-order Boundary Element
Method’, Proceedings of the 12th International
Offshore and Polar Engineering Conference,
Kitakyushu, Japan, 2002.
5. Fang, M-C, and Chen, G-R., ‘The Relative
Motion and Wave Elevation Between Two
Floating Structures in Waves’, Proceedings of
the 11th International Offshore and Polar
Engineering Conference, Stavanger, Norway,
pp 361–368, 2001.
6. Hong, S.Y., Kim, J.H., Kim, H.J. and Choi,
Y.R., ‘Experimental Study on Behavior of
Tandem and Side-by-side Moored Vessels’,
Proceedings of the 12th International Offshore
and Polar Engineering Conference, Kitakyushu,
Japan, pp 841 – 847, 2002.
7. Hong, S.Y., Kim, J.H., Cho, S.K., Choi, Y.R.
and Kim, Y.S., ‘Numerical and Experimental
Study on Hydrodynamic Interaction of Side-by-
side Moored Multiple Vessels’, Ocean
Engineering, Vol. 32, pp 783-801, 2004.
8. Huijsmans, R.H.M., Pinkster, J.A. and de
Wilde, J.J., 2001, ‘Diffraction and radiation of
waves around side-by-side moored vessels,
Proceedings of the 11th International Offshore
and Polar Engineering Conference, Stavanger,
Norway, pp 406 – 412, 2001.
9. Inoue, Y. and Ali, M.T., ‘A Numerical
Investigation on the Behaviour of Multiple
Floating Bodies of Arbitrary Arrangements in
Regular Waves’, Proceedings of the 13th
International Offshore and Polar Engineering
Conference, Honolulu,Hawaii, pp 558 – 565,
2003.
10. Kim, M.S., Ha, M.K. and Kim, B.W., ‘Relative
Motion Between LNG-FPSO and Side-by-side
Positioned LNG Carrier in Waves’, Proceedings
of the 13th International Offshore and Polar
Engineering Conference, Honolulu, Hawaii, pp
210 – 217, 2003.
11. Kodan, N., ‘The Motions of Adjacent Floating
Structures in Oblique Waves’, Proceedings of
3rd Offshore Mechanics and Arctic Engineering,
OMAE, New Orleans, Vol. 1, pp.206-213,
1984.
12. Koo, B.J. and Kim, M.H., ‘Hydrodynamic
Interactions and Relative Motions of Two
Floating Platforms with Mooring Lines in Side-
by-side Offloading Operation’, Applied Ocean
Research, Vol. 27, pp 292-310, 2006.
13. Lewandowski, E.M. and Naud, S.F., ‘Evaluation
of Relative Motions Between Closely Spaced
Vessels in Bidirectional Irregular Waves’,
Journal of Waterway, Port, Coastal and Ocean
Engineering, 2004, pp 58 – 61,
January/February 2004.
14. Lloyd, A.R.J.M, ‘Seakeeping – Ship Behaviour
in Rough Weather’, published by the author,
available through RINA, London, 1998.
15. Semaphore (Sea Power Centre - Australia),
‘Amphibious Ships’, Semaphore, Vol. 14, 2007
http://www.navy.gov.au/w/images/Semaphore_
2007_14.pdf. Retrieved 10 October 2011
16. van der Valk, C.A.C. and Watson, A., ‘Mooring
of LNG Carriers to a Weathervaning Floater –
Side-by-side or Stern-to-bow’, Offshore
Technology Conference, Houston, Texas, USA,
2005.
17. Xiang, X., Miao, Q., Chen, X. and Kuang, X.,
‘Validation on Coupled Motion Responses of
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2007.
Trans RINA, Vol 154, Part A2, Intl J Maritime Eng, Apr-Jun 2012
A-102 ©2012: The Royal Institution of Naval Architects
Panamax FHT Feeder Vessel
Ship Model Ship Model
LOA (m) 220.000 5.000 90.000 2.045
Beam (m) 44.000 1.000 21.000 0.477
Draught (m) 7.000 0.159 2.420 0.055
Displacement (tonnes) 47070 0.539 3660 0.043
Trim (degrees) 0.0 0.0 0.0 0.0
VCG (m) 10.000 0.227 5.500 0.125
LCG (m) 113.500 2.580 43.000 0.977
GM (m) 22.714 0.516 9.698 0.220
KM (m) 32.714 0.744 15.198 0.345
Pitch Radius of Gyration (m) 55.000 1.219 22.500 0.536
Roll Radius of Gyration (m) 15.400 0.338 7.350 0.173
Table 1 – Primary particulars of FHT and feeder vessel
Figure 1 – Floating Harbour Transhipper (mining). An SLV is in the well dock and a Capesize vessel is
moored alongside (foreground)
Trans RINA, Vol 154, Part A2, Intl J Maritime Eng, Apr-Jun 2012
©2012: The Royal Institution of Naval Architects A-103
Figure 2 – Stern Landing Vessel – bulk ore cargo
Figure 3 – model tests with the feeder vessel alongside the FHT
Trans RINA, Vol 154, Part A2, Intl J Maritime Eng, Apr-Jun 2012
A-104 ©2012: The Royal Institution of Naval Architects
Figure 4 – close up view of the model of the feeder vessel alongside the FHT model
Figure 5 – a view of the model of the feeder vessel moored inside the well dock of the FHT model
Trans RINA, Vol 154, Part A2, Intl J Maritime Eng, Apr-Jun 2012
©2012: The Royal Institution of Naval Architects A-105
Figure 6 - Heave motions as a function of wave period
Figure 7 - Pitch motions as a function of wave period
0
200
400
600
800
1000
1200
1400
02468101214
Heave -Total (mm)
Full Sc ale Wave Per iod ( s)
FHT (when Fee der inside well dock)
Feeder (when insi de FHT well dock)
FHT (when Feeder alongside)
Feeder (when alongside FHT)
Heading = 180 degrees
Nomina l wave height = 2.0m
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
02468101214
Pitch - Total (degrees)
Full Sc ale Wave Per iod ( s)
FHT (when Fee der inside well dock)
Feeder (when insi de FHT well dock)
FHT (when Feeder alongside)
Feeder (when alongside FHT)
Heading = 180 degrees
Nomina l wave height = 2.0m
Trans RINA, Vol 154, Part A2, Intl J Maritime Eng, Apr-Jun 2012
A-106 ©2012: The Royal Institution of Naval Architects
Figure 8 – Roll motions as a function of wave period
Figure 9 – Heave motions as a function of wave height
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
02468101214
Roll - Total (degrees)
Full Scale Wave Period (s)
FHT (when Fee der inside well dock)
Feeder (when insi de FHT well dock)
FHT (when Feeder alongside)
Feeder (when alongside FHT)
Hea ding = 180
degrees
Nominal wave height = 2.0m
0
200
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Heave - Total (mm)
Full Scale Wave Height (m)
FHT (when Feeder inside well dock)
Feeder (when insi de FHT well dock)
FHT (when Feeder alongside)
Feeder (when alongside FHT)
Heading = 180 degrees
Nomina l wave per iod = 10.0s
Trans RINA, Vol 154, Part A2, Intl J Maritime Eng, Apr-Jun 2012
©2012: The Royal Institution of Naval Architects A-107
Figure 10 – Pitch motions as a function of wave height
Figure 11 – Roll motions as a function of wave height
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Pitch - Total (deg rees)
Full Scale Wave Height (m)
FHT (when Fee der inside well dock)
Feeder (when insi de FHT well dock)
FHT (when Feeder alongside)
Feeder (when alongside FHT)
Heading = 180 degrees
Nomina l wave per iod = 10.0s
0
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2
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Roll - Total (degrees)
Full Scale Wave Height (m)
FHT (when Fee der inside well dock)
Feeder (when insi de FHT well dock)
FHT (when Feeder alongside)
Feeder (when alongside FHT)
Heading = 180 degrees
Nomina l wave per iod = 10.0s
Trans RINA, Vol 154, Part A2, Intl J Maritime Eng, Apr-Jun 2012
A-108 ©2012: The Royal Institution of Naval Architects
... -A significant increase in the operable seastate from less than 1.5 metres to more than 4 metres. (Macfarlane, Ballantyne, Ballantyne, & Lilienthal, 2012). -The elimination of environmental issues such as dust and product spillage. ...
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