Claims
- 1. A double hull tanker rebuilt from an existing single hull tanker comprising:an inner bottom hull formed from new inner bottom plating; an outer bottom hull formed from existing outer bottom plating; a plurality of connecting members disposed between and connecting said new inner bottom hull and said existing outer bottom hull in a spaced apart relationship to form a new double bottom hull; inner side hulls formed from existing inner side plating; outer side hulls formed from new outer side plating; and a plurality of connecting members disposed between and connecting said existing inner side hulls and said new outer side hulls in a spaced apart relationship to form new port and starboard double side hulls; wherein said new double bottom hull and said new double side hulls form a new double hull over at least a cargo carrying portion of said rebuilt double hull tanker.
- 2. The rebuilt double hull tanker according to claim 1, wherein said plurality of connecting members connecting said new inner bottom hull and said existing outer bottom hull comprise existing web framing, wherein said new inner bottom plating is laid on top of and connected directly to said existing web framing.
- 3. The rebuilt double hull tanker according to claim 2, wherein said existing web framing further comprises transverse web members.
- 4. The rebuilt double hull tanker according to claim 1, further comprising a bottom space formed between said new inner bottom hull and said existing outer bottom hull:wherein said bottom space comprises a distance H between said new inner bottom hull and said existing outer bottom hull measured at right angles; wherein H is not less than H=beam/15 or 2 meters, whichever is the lesser; and wherein a minimum value of H=1 meter.
- 5. The rebuilt double hull tanker according to claim 1, wherein said plurality of connecting members connecting said existing inner side hulls and said new outer side hulls comprise new connecting plates connected at a first end to said existing side plating of said existing inner side hull and connected at a second end to said new side plating of said new outer side hull.
- 6. The rebuilt double hull tanker according to claim 5, wherein said first end of said connecting plates are butt into said existing inner side hull plating in way of an existing supporting web frame and wherein said second end of said connecting plates are lapped on a face of new vertical side shell stiffeners of said new outer side hull.
- 7. The rebuilt double hull tanker according to claim 1, further comprising side spaces formed between said existing inner side hulls and said new outer side hulls:wherein a minimum side spacing is based on the deadweight of said tanker and extends either for the full depth of said rebuilt double hull tanker's side or from a top of said double bottom hull to a topside deck; wherein said minimum side spacing is defined by a distance W which is measured at any cross-section at right angles to said existing inner side hull and defined by W=0.5+deadweight/20,000(m) or 2 meters, whichever is the lesser; and wherein a minimum value of W=1 meter.
- 8. The rebuilt double hull tanker according to claim 1, further comprising temporary access holes cut into said existing side plating at a location above the turn of the bilge and existing web framing of said existing single hull, wherein said new inner bottom hull is installed through said temporary access holes in said existing side plating over said existing web framing.
- 9. The rebuilt double hull tanker according to claim 8, wherein said temporary access holes are only cut on either a port side or a starboard side of said tanker at a time and in way of only one adjacent cargo hold at a time and the integrity of the opposite side of said tanker is kept intact to maintain the structural strength of said tanker.
- 10. The rebuilt double hull tanker according to claim 8, further comprising inserts, wherein said temporary access holes are renewed after said new inner bottom hull is installed with said inserts to close said access holes in said existing side plating.
- 11. The rebuilt double hull tanker according to claim 10, wherein said inserts comprise portions of said existing inner side hull plating that were cut away to form said temporary access holes in said existing inner side hull.
- 12. The rebuilt double hull tanker according to claim 8, further comprising temporary access apertures cut into a lower portion of existing longitudinal bulkheads and existing longitudinal bulkhead stiffener members, wherein said new inner hull plating is installed through said temporary access apertures.
- 13. The rebuilt double hull tanker according to claim 12, further comprising bulkhead inserts, wherein said temporary access apertures in said lower portion of said longitudinal bulkheads are renewed after said new inner bottom hull is installed with said bulkhead inserts to close said temporary access apertures in said lower portion of said existing longitudinal bulkheads and said existing longitudinal bulkhead stiffener members.
- 14. The rebuilt double hull tanker according to claim 13, wherein said bulkhead inserts comprise said lower portions of said existing longitudinal bulkhead portions that were cut away to form said temporary access apertures.
- 15. The rebuilt double hull tanker according to claim 1, wherein said rebuilt double hull tanker comprises multiple cargo holds and wherein said new inner bottom hull is installed simultaneously in more than one cargo hold with adjacent cargo holds being worked from alternative port and starboard sides of said tanker to retain structural integrity and sufficient strength during the installation process of said new inner bottom hull.
- 16. The rebuilt double hull tanker according to claim 1, wherein said rebuilt double hull tanker maintains substantially the same cargo carrying capability as said existing single hull tanker by:converting one or more existing ballast tanks to cargo tanks; and using a space between one or both of said new inner bottom hull and said new outer bottom hull of said new double bottom hull and said new outer side hulls and said existing inner side hulls of said new side double hulls as new ballast tanks.
- 17. The rebuilt double hull tanker according to claim 1, wherein said rebuilt double hull tanker reuses substantially all of the existing hull structure.
- 18. The rebuilt double hull tanker according to claim 1, wherein the draft of said rebuilt double hull tanker is reduced for the same cargo load through the use of said new double side hulls being formed by installing said new outer side hull externally over said existing inner side hull, resulting in an increase in buoyancy for said rebuilt double hull tanker as compared to said existing single hull tanker.
- 19. The rebuilt double hull tanker according to claim 1, wherein a turn of the bilge and a portion of said existing single hull proximate said turn of the bilge is cut-away to form access holes to allow for installation of said new inner hull, wherein said cut-away portion of said turn of the bilge is reused after installation of said new inner hull.
- 20. The rebuilt double hull tanker according to claim 19, further comprising new bottom filler pieces connected to each outboard end of said new double bottom hull where said existing turn of the bilge was cut-away and scribed to match said existing outer bottom hull and directly supporting said inner side hulls.
- 21. The rebuilt double hull tanker according to claim 20, wherein one of said cut-away portions of said turn of the bilges is connected to an outboard end of each of said bottom filler pieces.
- 22. The rebuilt double hull tanker according to claim 20, further comprising new outer side filler pieces connected over an exterior of said existing port and starboard inner side hulls and connected to said existing turn of the bilges.
- 23. The rebuilt double hull tanker according to claim 22, further comprising connecting plates for connecting said new outer side filler pieces to said existing inner side hull, wherein said connecting plates are butt into said existing inner side hull in way of a supporting web frame and said connecting plates are connect to the new structure by lapping on a face of new outer side hull stiffeners.
- 24. The rebuilt double hull tanker according to claim 22, wherein said new outer side filler pieces further comprise new outer portions of topside deck plating that is scribed out to match a contour of the shear strake of existing topside deck plating.
- 25. The rebuilt double hull tanker according to claim 1, wherein said rebuilt too double hull further comprises:said existing outer bottom hull plating and said new inner hull plating connected in a spaced-apart relationship by existing transverse web framing to form a central portion of said rebuilt double bottom hull; new longitudinal stiffener members disposed on a topside of said new inner hull plating; new bottom filler pieces fitted and connected to an outboard end of said central portion of said rebuilt double bottom hull, said bottom filler pieces having a width substantially equal to a width of said new double side hulls; existing port and starboard turn of the bilges connected to each outboard end of said new bottom filler pieces; and new side filler pieces fitted and connected to said existing turn of the bilges, said new side filler pieces comprising new outer side hull plating, new connecting plates extending inward from said new outer side hull plating for connection to said existing inner side hull plating, and new port and starboard outer portions of topside deck plating fitted and connected to an outer peripheral edge of existing topside deck plating.
- 26. The rebuilt double hull tanker according to claim 25, wherein one or more of said new inner bottom hull, said new bottom filler pieces, and said new side filler pieces are prefabricated.
- 27. The rebuilt double hull tanker according to claim 1, wherein existing topside deck plating, machinery, and equipment is substantially undisturbed during said double hull rebuild.
- 28. The rebuilt double hull tanker according to claim 1, wherein said new inner bottom plating further comprises a plurality of longitudinal stiffening members extending from a topside of said new inner bottom plating, and wherein a bottom side surface of said inner bottom plating is connected directly to said plurality of connecting members.
- 29. The rebuilt double hull tanker according to claim 28, wherein existing brackets between existing longitudinal bulkheads and sad existing transverse framing members are cut out for installation of said new inner bottom plating, notched to form cutouts to accommodate said plurality of longitudinal stiffening members extending upward from said new inner bottom plating, and re-installed between said new inner bottom plating and said existing longitudinal bulkheads.
- 30. The rebuilt double hull tanker according claim 1, wherein existing outer wing tank brackets between existing outer wing tanks and existing transverse framing is cut out and removed, and stiffening of said existing wing tanks is provided by said new double side hulls.
- 31. The rebuilt double hull tanker according to claim 1, further comprising faired sections formed between said new double side hulls and said existing side hull of said single hull, wherein said faired sections provide a relatively smooth transition between said new outer side hulls and said outer hull of said existing single hull proximate a bow section and a stern section for a smoothing hydrodynamic transition fore and aft in the area where said new double side hull and said existing single side hull meet.
- 32. The rebuilt double hull tanker according to claim 31, wherein said faired sections partially comprise an elastomer fairing compound.
- 33. The rebuilt double hull tanker according to claim 1, wherein said rebuilt double hull tanker has an increased cargo carrying capability as compared to said existing single hull tanker.
- 34. The rebuilt double hull tanker according to claim 1, wherein said rebuilt double hull tanker has a reduced draft at the same cargo capacity as compared to said existing single hull tanker.
- 35. The rebuilt double hull tanker according to claim 1, wherein said rebuilt double hull tanker has an increased beam due to the installation of said new double side hulls externally over said existing inner side hulls resulting in a greater displacement at the same draft for said rebuilt double hull tanker as compared to said existing single hull tanker.
- 36. A method of rebuilding an existing single hull tanker into double hull tanker having an internally rebuilt double bottom and externally rebuilt double sides, said method comprising:cutting out a section of the turn of the bilge on one side of said tanker, including at least a portion of a side shell of said existing single hull above existing web framing to form access holes in said side shell, wherein said cut-out section of said turn of the bilge covers one cargo hold; cutting out a lower portion of one or more longitudinal bulkheads proximate said one side above said existing web framing to form access apertures in said longitudinal bulkheads, wherein said cut-out lower portion covers said one cargo hold; installing a new inner bottom hull in one or more sections from said side of said tanker through said access holes and internally over said existing web framing to cover said cargo hull fore and aft and side to side from a longitudinal bulkhead to said side shell; connecting said new inner bottom hull to a distal end of said existing web framing so that said new inner bottom hull is in a spaced-apart relationship to said existing outer bottom hull to form a portion of a new double bottom hull; installing a new bottom filler piece to an outboard end of said portion of said new double bottom hull; installing bulkhead inserts to close said access apertures in said lower portion of said longitudinal bulkhead; installing inserts to close said access holes in said side shell; connecting said turn of the bilge to an outboard end of said bottom filler piece; installing a new side filler piece including a new outer side hull externally over said existing inner side hull; connecting said new outer side hull to said existing inner side hull using connecting plates to connect said new outer side hull in a spaced-apart relationship to said existing inner side hull to form a portion of a new double side hull; connecting said new side filler piece to an upper end of said turn of the bilge; connecting a new outer portion of topside decking to an outer peripheral edge of existing topside decking; cutting out a section of said turn of the bilge on an opposite side of said cargo hold, including at least a portion of a side shell of said existing single hull on said opposite side above said existing web framing to form access holes in said side shell on said opposite side, wherein said section of said turn of the bilge covers said one cargo hold; installing said new inner bottom hull in one or more sections from said opposite side of said tanker through said access holes and internally over said existing web framing to cover said cargo hull fore and aft and side to side from said longitudinal bulkhead to said opposite side shell; connecting said new inner bottom hull to a distal end of said existing web framing so that said new inner bottom hull is in a spaced-apart relationship to said existing outer bottom hull to form a second portion of a new double bottom hull; installing a second bottom filler piece to an outboard end of said second portion of said new double bottom hull; installing an insert to close said access holes in said opposite side shell; connecting said turn of the bilge to an outboard end of said second bottom filler piece; installing a new side filler piece including an outer side hull externally over said existing inner side hull of said opposite side and an upper end of said turn of the bilge; connecting said new outer side hull to said existing inner side hull of said opposite side using connecting plates to connect said new outer side hull in a spaced-apart relationship to said existing inner side hull to form a new double side hull; connecting said new side filler piece to an upper end of said turn of the bilge; connecting a new outer portion of topside decking to an outer peripheral edge of existing topside decking; and repeating the above steps for each cargo hold of said tanker.
- 37. The method according to claim 36, wherein said existing single hull tanker comprises a multiple cargo hold tanker, said method further comprising:installing said new inner bottom hull simultaneously in more than one cargo hold with adjacent cargo holds being worked from alternative port and starboard sides of said tanker in order to retain structural integrity and sufficient strength during the installation process of by said new inner bottom hull.
- 38. The method according to claim 36, wherein said method further comprising:cutting out and removing existing support brackets between said side shell and said web frames and between said longitudinal bulkheads and said web frames; modifying said brackets to provide cutouts in a lower edge for new longitudinal stiffeners to pass through said brackets; and reinstalling said brackets on top of said new inner bottom hull.
- 39. The method according to claim 36, wherein said method further comprises renewing and reusing one or more of said existing turn of the bilges and said lower portions of said longitudinal bulkheads.
- 40. The method according to claim 36, wherein said method further comprises prefabricating one or more of said one or more sections of new inner bottom hull, said new bottom filler pieces, and said new side filler pieces.
- 41. The method according to claim 36, wherein said method further comprises:butting said connecting plates into said existing inner side hull in way of a supporting web frame; and lapping said new outer side hull on a face of a new vertical side shell stiffener according to allowable fit up tolerances.
- 42. The method according to claim 36, wherein said method further comprises installing said new inner bottom hull internally over said existing outer bottom hull so that a baseline of said rebuilt double hull tanker is substantially the same as a baseline of said existing single hull tanker and installing said new outer side hull externally over said existing inner side hull in order to increase a beam of said rebuilt double hull tanker as compared to said existing single hull tanker resulting in an increased buoyancy and decreased draft for the same cargo load.
- 43. The method according to claim 36, wherein said method further comprises converting one or more ballast tanks of said existing single hull tanker into cargo tanks in order to maintain substantially the same cargo carrying capacity or an increased cargo carrying capacity for said rebuilt double hull tanker as compared to said existing single hull tanker.
- 44. A method of rebuilding an existing single hull tanker into a rebuilt double hull tanker comprising the steps of:forming a new double hull comprising a new double bottom hull and new double side hulls over at least the cargo carrying portion of said rebuilt double hull tanker; internally installing a new inner bottom hull through access holes cut into the sides of the tanker and over an existing outer bottom hull of said existing single hull tanker; connecting said new inner bottom hull to said existing outer bottom hull in a spaced apart relationship to form said rebuilt tanker having said new double bottom hull having the same baseline as said existing single hull tanker; externally installing a new outer port side hull over an existing inner port side hull of said existing single hull tanker and externally installing a new outer starboard side hull over an existing inner starboard side hull of said existing single hull tanker; and connecting said new outer port side hull in a spaced apart relationship to said existing inner port side hull and connecting said new outer starboard side hull in a spaced apart relationship to said existing inner starboard side hull to form said rebuilt tanker having a said new double side hulls having an increase beam as compared to said beam of said existing single hull.
CLAIM OF PRIORITY
This application claims benefit under 35 U.S.C. §119(e) to Provisional Application No. 60/394,577 filed on Jul. 9, 2002.
US Referenced Citations (6)
Number |
Name |
Date |
Kind |
5189975 |
Zednik et al. |
Mar 1993 |
A |
5218919 |
Krulikowski, III et al. |
Jun 1993 |
A |
5899162 |
Beaupre et al. |
May 1999 |
A |
6009821 |
Al-Rammah et al. |
Jan 2000 |
A |
6170420 |
Hagner et al. |
Jan 2001 |
B1 |
6357373 |
Hagner et al. |
Mar 2002 |
B1 |
Foreign Referenced Citations (2)
Number |
Date |
Country |
61-24685 |
Feb 1986 |
JP |
61-24686 |
Feb 1986 |
JP |
Provisional Applications (1)
|
Number |
Date |
Country |
|
60/394577 |
Jul 2002 |
US |