Patrick Keating 1 of 9 16 November 2009 Concept report. Palm Island Frond C – Tip Lot. Private marina jetty. This report is prepared for Sheikh Ibrahim Sharbatly, the owner of the above property (hereinafter referred to as the owner). It is prepared for his use and may be copied and distributed for the purpose of designing, constructing and gaining regulatory approvals for the construction of a private marina jetty on the Palm Jumeirah Tip lot C for the berthing of private non commercial pleasure craft. Definitions used in this report. Palm – Palm jumeriah island Tip Lot – The construction plot at the very end of frond C of the palm. Boundary- The demarcated boundary of the tip lot. Beach – The area between the boundary and the water line. HAT – Highest astronomical tide LAT – Lowest astronomical tide MHWS – Mean high water springs MHWN – Mean high water neaps MWL – Mean water level MLWN – Mean low water neaps MLWS – Mean low water springs CD – Chart datum taken as the datum mentioned on sea navigation charts. DMD – Dubai municipality datum Plot Level – The proposed finished plot ground level. Freeboard – Distance from the water line to the working deck level. 1. Aim of report. To advise on the best location for a private marina jetty at the owners property on Palm Island taking into account all environmental and operational issues. 2. Location. Palm Jumeirah Island, Dubai, UAE. Frond C tip lot. The area considered in this report is bounded by the following coordinates/control points and the water area up to 100 metres around the tip lot outside these points. Serial Nakheel control points WSG84 lat and long 1 N2780271.78 E481145.42 N25 07.696 E55 08.783 N E S W YACHTING WORLDWIDE LTD Yacht and marina consultancy
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Patrick Keating 1 of 9 16 November 2009
Concept report.
Palm Island Frond C – Tip Lot.
Private marina jetty.
This report is prepared for Sheikh Ibrahim Sharbatly, the owner of the above property (hereinafter referred to as the owner). It is prepared for his use and may be copied and distributed for the purpose of designing, constructing and gaining regulatory approvals for the construction of a private marina jetty on the Palm Jumeirah Tip lot C for the berthing of private non commercial pleasure craft. Definitions used in this report. Palm – Palm jumeriah island Tip Lot – The construction plot at the very end of frond C of the palm. Boundary- The demarcated boundary of the tip lot. Beach – The area between the boundary and the water line. HAT – Highest astronomical tide LAT – Lowest astronomical tide MHWS – Mean high water springs MHWN – Mean high water neaps
MWL – Mean water level MLWN – Mean low water neaps MLWS – Mean low water springs CD – Chart datum taken as the datum mentioned on sea navigation charts. DMD – Dubai municipality datum Plot Level – The proposed finished plot ground level. Freeboard – Distance from the water line to the working deck level.
1. Aim of report. To advise on the best location for a private marina jetty at the owners
property on Palm Island taking into account all environmental and operational issues.
2. Location. Palm Jumeirah Island, Dubai, UAE. Frond C tip lot. The area considered in this report is bounded by the following coordinates/control points and the water area up to 100 metres around the tip lot outside these points.
Serial Nakheel control points WSG84 lat and long 1 N2780271.78 E481145.42 N25 07.696 E55 08.783
N
E
S
W
YACHTING WORLDWIDE LTDYacht and marina consultancy
When looking out from the tip towards the crescent the tip centre line is orientated at 80 degrees magnetic. Attached drawing at appendix A is the affection plan issued by Nakheel for this plot. Appendix B shows the whole site in relation to other fronds and the crescent with dimensions and orientation.
3. Purpose of marina jetty. The jetty is to be constructed to enable the berthing of the owners private pleasure craft, including a motor yacht, open fishing boats, enclosed fishing boats and other small powered and non powered leisure vessels. The jetty has been designed and sized to take vessels up to 50 metres and 300 tonnes GRT.
4. Climatic conditions. For the purpose of this report the only significant climatic factors are wind direction, wind speed and frequency of direction. Precipitation, temperature and pressure are not significant in the purpose of this report. An evaluation of the wind based factors has been carried out and the following conclusions have arisen:
a. The climatic data used for this report was derived from the following sources: i. US Government Atlas of Pilot charts for the Indian ocean area, Third
edition 1991.
ii. British Admiralty Sailing directions – Persian Gulf Pilot NP63 – 12th edition.
iii. Meteorological station of Dubai civil aviation department.
b. The data from the above sources was collated and is shown in the table
below. This was then analysed and has been summarised in the wind rose charts shown at appendix C “Wind rose by month for the Gulf region” which is attached. This data shows that the prevailing winds are predominantly from the North West quadrant. The highest wind speeds have also been recorded from this direction. The table clearly shows that the winds from the North West quadrant will have the most effect on any floating structure built on the palm. The effect of this wind data is shown graphically applied to a palm overview at Appendix D where it can be clearly seen which areas are protected and which are at risk for the prevailing wind conditions.
Patrick Keating 3 of 9 16 November 2009
Key
Wind direction = The direction from which the wind is blowing % = The percentage of time the wind is blowing from this direction
Mean wind speed = Averaged wind speeds from this direction Max wind speed = The maximum sustained wind speed (not maximum gust strength)
c. The highest recorded wind data (maximum gust strength) for the period 1997 to 2005 is reproduced in the table below. This data was recorded at the meteorological station at Dubai Airport and therefore could be 10% lower than actual wind speeds across sea areas. The highest wind speed during this period was recorded at 71 knots (116 kmh) with winds in excess of 50 knots on a number of occasions.
d. Conclusion based on wind data. Due to the predominance of wind from the
North West quadrant and the fact that it can reach significant force at times (Force 11) it is prudent to locate any marina jetty where possible in a location that provides maximum protection from this wind direction.
5. Sea Conditions/wave data. The palm structure is a new development and there is no historical wave data for inside the breakwater to base any decision on. However in looking at this aspect of the location the following has been taken into account.
a. The area inside the breakwater is protected and is not subject to major sea conditions. However due to the fact that many of the structures to be built on both the crescent and fronds are not yet complete, the effects of wind on water inside the breakwater have not been sufficiently documented at present.
b. Although protected from the open sea there is a considerable fetch from some angles that could impact on any marine structures that are built and this should be taken into consideration when deciding on the location of such structures. The fetch from the north is of prime concern as winds from the North west have historically been the strongest and this is the prevailing direction. As the wind does veer to the north frequently this has a significant effect.
c. The most exposed area of the plot is the extreme tip and this area should be
avoided if possible. The south side of the plot offers the best protection from any water generated forces from the prevailing wind.
d. Conclusion. To protect any vessels and jetties from wave effect the best
location is to the south side of the plot.
Patrick Keating 5 of 9 16 November 2009
6. Operational aspects. The design and location of the jetty on this plot was approved in 2006 by Nakheels design team. The approved location was on the south side of the plot in the position shown in the drawings at appendix B, C and D. The owner has therefore proceeded with construction of the property on this basis. Prior to selecting the south side of the plot the following was taken into consideration:
a. Nakheels operational plan for the water area allows the use of power vessels outside an arc formed by the tips of each frond and the crescent. Many vessels transiting around the inside of the palm area will tend to take the shortest route which will mean going close to each tip lot. Therefore it is prudent to locate any jetty to the side of the plot and not on the end to minimise risks to navigation. Any jetty protruding directly from the tip centre line is a potential hazard to navigation.
b. Asthetics. During 2005 and 2006 the jetty location was discussed with a number of Nakheel managers and technical advisors and the consensus was that Nakheel did not want anything protruding beyond the tip plot limit. The owner took this into account when planning his jetty on the south side of the plot. This would give a clean visual look to the palm for any craft transiting the waterway.
7. Water depth. Attached at Appendix J is a bathymetric survey carried out on 17 Nov
2009 of the area out to 200 metres from the plot limit. The survey indicates that there no major differences in siltation rates between the North and East sides of the plot. However the south side shows a different profile to the other sides (see water depth profiles at Appendix J). The south side appears to be shoaling more gently than the other two sides and has more depth of water in the area suitable for the jetty. The critical area for the jetty is 70 to 90 metres from the plot limit and the South side is the only area that exhibits the correct characteristics for the vessels requirements. The graph below gives a summary of average water depth below DMD at significant points for the jetty location. The vessel shape is based on a yacht with a draft of 2.5 metres and how it relates to the water depth profile at LAT. The coloured lines indicate the water depth relating to distance from the boundary at each side of the plot.
-7.00
-6.00
-5.00
-4.00
-3.00
-2.00
-1.00
0.00
1.00
2.00
3.00
North side
East side
South side
50 55 60 65 70 75 80 85 90
Zero = DMD
Metres from boundary
Vessel shape 2.5 draft at LAT
Patrick Keating 6 of 9 16 November 2009
The conclusion from the water depth analysis is that the tip centreline (East side) location has the worst water depth profile for placing a jetty. The best location to allow plenty of water depth and a margin of safety is the South side of the plot.
8. Proposed Jetty structure. The original design and approval of the jetty is based on a system provided by Walcon Marine of UK. Walcon is the UKs largest marina construction company and has built many marinas world wide including the DIMC marina at Mina Seyahi and the marinas used every year for the Dubai International Boat show.
a. The jetty proposed by Walcon, is their system 2000 which consists of:
i. Loading: 0.75kN/m2 live load with 25% reserve.
ii. Freeboard: 700mm
iii. Draft: 300mm
iv. Structure: Welded aluminium braced frame from marine grade aluminium alloy to international designation 6082 or 6061.
v. Decking: Hardwood decking from audited and sustainable forestry
which ensure a long service life. Boards will be planed and grooved to provide a non slip surface and fixed with stainless self tapping screws.
vi. Floatation. Expanded Polystyrene floats encased in fibre reinforced concrete. The benefit of these floats are that they are extremely durable and even if the fibre concrete case is punctured there is no loss of floatation.
vii. Piles: Jetty to be fixed on steel piles 503 mm diameter by 16 mm wall
thickness. Piles to be driven to a suitable depth to provide secure mooring. Each pile will be placed to ensure sufficient height to retain jetties in position during maximum storm surge conditions. Each will be covered with a white fibreglass pile cap.
viii. The jetty has been designed to take the berthing loads of a 40 metre
motor yacht of 300 tonnes GRT plus a variety of smaller craft.
b. Jetty access. The jetty will be accessed across the beach via a wooden decked structure designed to blend into the environment. This will extend from the beach area to the MWL line leaving sufficient gap at the beach end for the passage of beach cleaning and replenishment vehicles. From there an aluminium alloy bridge will be fixed to land on the floating jetty as shown in appendix A.
Patrick Keating 7 of 9 16 November 2009
c. Jetty services. The jetty will be equipped with service equipment supplied by ROLEC of UK. ROLEC is a provider of service equipment to the international marina industry. The services proposed for this jetty are housed in a number of separate weatherproof service bollards all with self contained illumination as follows:
i. 1 Main service bollard with 250Amp 3 phase supply with 200 Amp 4 pole MCCB and 200 Amp 4 pole RCD. Also containing TV and Telephone connection points. 1 x water point with inline anti contamination valve.
ii. 1 secondary service bollard containing 2 x 16 Amp and 2 x 32 Amp single phase supplies with double pole MCBs for each and 1 x 100Amp double pole RCD. Also includes telephone and TV connections plus water point with inline anti contamination valves.
iii. 1 x self contained sewage pump out station. With all associated
pumps, pipe work and controls to pump out the holding tanks of any moored vessels and discharge into the main shore based sewage system.
iv. 1 x fire hydrant cabinet with 25 metres of hose, fire extinguisher and
life buoy.
v. 2 x SOS bollards with illumination and containing fire extinguisher, first aid kit and life buoy.
vi. 2 x Emergency ladders for escape from the water will be provided by
Walcon.
Patrick Keating 8 of 9 16 November 2009
Bea
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Dra
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By:
Pat
rick
Kea
ting
Dat
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8 Ju
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Fetch 1
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ope
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ave
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Win
d. P
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from
the
Nor
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The
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of p
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n fro
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ith th
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d en
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nmen
tal c
ondi
tions
at t
he
site
.
Pile
loca
tions
are
indi
cativ
e at
pre
sent
. Fi
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ocat
ion
will
be
spec
ified
by
WA
LCO
N
34.50
49.4
6
Pile
Pile
PileP
ile
Pile
2.90
N
E
S
W
9. Summary. The data available can be summarised in the following table. It clearly
indicates the east side of the plot (extreme tip) is the most dangerous location for any jetty and boats. The north side provides better protection, especially from navigation hazards. However the best location is the south side of the plot, where there is complete protection from prevailing winds, fetch and navigation hazards.
Patrick Keating 9 of 9 16 November 2009
This applies to the palm in general in that the south side of all the fronds is the safest place to locate a jetty. In this location 80% of the fronds would be sheltering the location and in the remaining cases the vessels would be berthed head to the prevailing wind, minimising wind cross section and forces.
Location Prevailing
wind Wave
conditions Navigation operations Water Depth
North side Exposed Acceptable Protected Acceptable
East side Very exposed
Very exposed
Very Exposed Poor
South side Protected Protected Protected Good
10. Conclusion. Having studied all the data available the jetty should be located on the south side of the plot as the safest location. The owner has already designed and completed significant works based on this location. The tip centreline of the lot (east side) should be avoided as a jetty location.
Appendices. Appendix A –Affection plan issued by Nakheel. Appendix B - First group drawing 001 Jetty details. Appendix C – Distances and orientation to principle structures. Appendix D– Wind rose for the Gulf Area. Appendix E – Effects of wind on the proposed location. Appendix F – Area of impact for wind driven waves/fetch. Appendix G –Walcon jetty information. Appendix H - Datum Chart of water depths, tides and datums. Appendix J – Bathymetric survey drawing. Appendix K – Rolec jetty service equipment specification and drawings.
491 metres from MHW to crescent
335 m MHW to
MHW302 m MLW to
MLW
303 m MHW to
MHW276 m MLW to
MLW
40 M
JETTY LOCATION
24.3
226.5
9
26.28
451 metre
s fro
m M
HW to
jetty
build
ing
NORTH
Drawn by: Date:
Palm Jumeriah
Principal dimensions
Patrick Keating 10 Nov 2009 Approved Yes/No
Scale: Not to scale
N
E
S
W
11
4.6
5
Plo
t
Cle
ar b
ea
ch
Are
a
188.97
349.6094.49 56.69
28.35
28
3.4
6
Plo
t
Detail as per development plan
Section through plot A-A showing jetty and 40 meter yacht position in relative scale.
A
A
Blue = % of
time wind is
blowing
from this
direction.
Green =
Mean wind
speed in
knots from
direction
Red =
Maximum
wind speed
from direction
Wind Rose by month the Gulf region.
Data derived from the USA Atlas of pilot charts for the Indian Ocean, Third edition 1991. Prepared by P Keating, 10 Nov 2009