Problems and Opportunities in the Design of Entrances to Ports and Harbors Proceedings of a Symposium (1981) / Chapter Skim
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Concerns of Ship Operators
Concerns of Ship Operators
Pages 45-52
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From page 45... ...
, · Channel depths, Regularity of bottom and banks, Water waves, Strength and uniformity of water currents, and Quantity and quality of information provided to the shiphandler regarding ship's position relative to all the above. This list assumes that the ship has adequate inherent controllability, shipboard aids to navigation, machinery, communications, pilotage, and crew, all of which are outside the scope of harbor entrance design.
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From page 46... ...
Examples are recent studies conducted with large researab simulators, such as those of the Netherlands Ship Model Basin, 8 CAORFt,9 and the Swedish Maritime Research Center.~° All such large facilities offer outside-view displays combined with carefully duplicated wheelhouse mockups, shipboard navaids, etc. A number of less expensive real-time research simulators have recently been developed that employ cathode-ray-tube perspective scenes instead of outside views.
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From page 47... ...
~ l CURRENT ORDERED RUDDER ANGLE PROPE LLER REV.S F ~ Isure 1 MAN- SH I P CONTR OL LOO P HUMAN MOTION PREDICTING INTERNAL MODEL .
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From page 48... ...
The simplest is, of course, direct local knowledge based solely on the experience of earlier ships In that area and the reports of pilots. Regarding analysis, the basic calculation is simply to subtract the ship's static draft at its lowest point from the calculated water depth at the shallowest spot.t Allowances are then made for ship sinkage and trim at speed, possible heel, ship motions in waves, tidal height, and bottom siltation and debris, as shown in Figure 2a.
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From page 49... ...
_ _ _ _ _ _ _ ~ _ ~ NET UNDERKELL CLEARANCE NO MINAL CHANNEL BED LEVEL ~ SOUNDING ACCURACY SEDI MENTATION BETWEEN DREDGINGS TOLERANCE FOR DREDGING F;9Ure 2a E-8-80-26 E-8-80-27 CONVENTIONAL NET BOTTOM CLEARANCE CALCULATION DEFINITIONS (FRO M PIANC RE F
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From page 50... ...
Tables 1 and 2 briefly reflect my personal views on the main strengths and limitations of each of the methods discussed above for horizontal and vertical clearances. ~ hope that these comments fairly reflect the problems of a ship operator when assessing how wide and how deep a harbor entrance must be for a particular vessel.
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From page 51... ...
Presently liaised regarding ahallow water wave ~pectra and r~po~ue a~plitudo operators tor varioua ship types.
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From page 52... ...
The pilots will very quickly realize or come to learn in the Houston Ship Channel, for instance, two ships must not pass on suab and suab a bend. The National Transportation Safety Board begins to analyze accidents, and they notify the coast Guard to tell the pilots that they shouldn't pass there, but the people who designed the port, the channel, didn't put a note on the plan that says ships should not pass on that bend.
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