Passenger cruise vessels as well as ferries have grown drastically in size and volume during the last fifteen years. The issue is to maximise the efficient revenue generating space at minimised investment costs. The first step was to increase the superstructure up to the transom of the vessel or even inclined aftwards. The following step was to lengthen the superstructure up to collision bulkhead or even forward of that. Superstructure decks have become square shaped with minimum roundings. This development requires also more displacement and stability to carry the increased above-waterline volume. Block coefficient has increased from 0,55 - 0,57 up to 0,72. It is extremely difficult, if not impossible, to extrapolate the performance capabilities such as powering, seakeeping and manoeuvrability only on basis of references, when there are actually no close references available. Most of the statistical prediction (calculation) methods do not really cover the latest developments, there is no statistics behind. Improperly located high displacement volume may induce poor wakefield and heavy propeller induced vibrations. Extreme deck shape leads easily to extreme type of hull form and e.g. bow flare. Introduction of wide bow door and ramp is a typical and good example of an utmost difficult design task: When are we going too far in the deck and bow flare shape? Unfortunately several sad references exist. Greed for the last deck square metres or lane metres or ramp centimetres has led to poor or unacceptable performance in heavy or even in moderate head and bow quartering seas, heavy loss of speed, wave induced impact loads, noise and whipping vibrations occur. And to avoid this the master reduces speed or changes course and cannot keep the schedule. High superstructure means also large windage area. Crabbing manoeuvre in limited harbour basins becomes critical and sometimes even impossible already at moderate m/s wind speeds. Adequate thrust at each manoeuvring mode to all required directions becomes essential as a function of windage area. This paper describes some design and full scale experience of seakeeping and crabbing performance of passenger vessels and ferries. Simple design guidance is also developed.
Practical experience from seakeeping and manoeuvring calculations and model tests, designer's approach, passenger cruise vessels and ferries
Praktische Erfahrung mit Berechnungen, Modelltests und Entwurfsmethoden bezüglich der Manövrierfähigkeit und des Verhaltens bei Seegang von Fahrgastschiffen und Fähren
1998
19 Seiten, 19 Bilder, 5 Quellen
Conference paper
English
Fahrgastschiff , Fährschiff , Manövrierfähigkeit , Entwurf , Modellversuch , Berechnungsmethode , Schiffsaufbau , Kollision , Schott , Stabilität , Völligkeitsgrad , Wasserverdrängung , Vorhersage , Statistik , Schiffspropeller , Vibration , Windbelastung , Abdrift , Kollisionsschutz , Verdrängungsvölligkeitsgrad , Seegangsverhalten
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