Marine Design, 14-15 September 2011, Coventry University, UK
As one can see, only such factors as visibility (though not completely) and navigation lights are regulated while others being the matter of designers’ experience. Such a simple solution as placing easily accessible drawer-style fridge under driver’s seat will avoid the situation of driver’s inattention when he bends down to get a drink.
Safety is also related to other activities associated with boating, but not with the boat itself – boat lifting and storage, swimming, using tenders and water toys, boarding, using fishing
gear, cooking on board,
maintenance, etc. – those are not regulated by standards but designers have to consider them during the design process.
Thus designers’ success in developing small pleasure craft is closely associated with knowledge of regulations, but also with personal experience with boats and ability to perform detailed analysis of boat operation.
5. COMFORT
Comfort is subdivided into psychological and physiological. Psychological factors are quite subjective and provided by rational planning of space, general feeling of the boat’s safety, reliable equipment, pleasant crew, familiar activity and environment and many other sensitive matters. Though a skilled designer can treat them based on his experience those are not easy to quantify.
Physiological factors of comfort are
measurable; they are related to psychological conditions of people on board and are subject to assessment:
Noise Lighting Climate Accelerations Accommodation
Those factors are discussed in detail by the author in [3]. Comfort requirements are specified in comfort class rules of classification societies such as Det Norske Veritas (DNV),
Lloyds Register (LR), American Bureau of
Shipping (ABS), etc.; some factors are included in international standards such as ISO or IMO, also in national sanitary regulations or directly specified in customers’ requirements. Officially a ‘comfort class’ is issued for luxury yachts or passenger craft, but many of comfort class requirements are worth considering on smaller boats.
Unfortunately, from a customers’ point of view comfort is often mistaken with interior design that means how soft the cushions are and how big is mirror in bathroom; later on, a ‘light and sporty boat’ turns out uncomfortable in terms of air conditioning or sound privacy. In this respect all comfort noted above should be considered at initial design stages and not on a residual basis.
5.1 NOISE
Noise is one of widespread reasons of discomfort on boats; scope of requirements is summarized in Table 2 where lower numbers are recommended and higher numbers are acceptable (but not always practically achievable on small boats). There are two major factors to consider:
General noise reduction; Sound privacy
General noise reduction is targeted to avoiding hearing damage, ensure intelligible communication and ability to hear alarms, easy communication and intense levels of concentration, guarantee recreation through sleep. As an example, for luxury yachts a level of sound of 20dBA allows classical music listening. For the ability to sleep the sound level
should not generally acceptable exceed 60dBA that is for crew compartments on
commercial craft and cabins on small boats. Noise level of less than 80dBA allows verbal communication. For noise of more than 85…100dBA one should use headset to protect from hearing injury [4].
Being on a boat people are confined to a rather tight environment, so the ability to have some privacy is very important. Sound privacy is estimated using sound transmission class (STC) indicating how many decibels of sound are reduced between neighboring compartments and usually achieved with proper sound insulation of accommodation
bulkheads, doors, etc. and layout
planning. More insulation usually means thicker bulkheads that should not be overseen at the concept development stage. Recommended design measures for noise reduction related to general design and styling are the following:
Selection of low-noise machinery and equipment and its correct installation apart from inhabitable spaces.
Sound insulation and absorption, sound insulation covers for some equipment, carpets and soft panels in interior or sandwiches structures.
Avoiding possible ways of sound distribution by rational arrangement of outlets, openings and ducts out of public areas.
Air conditioners and generators are primary sources of noise on most of yachts at rest. Unfortunately, light materials are not too efficient for sound insulation though the use of heavy materials on a performance boat is limited.
5.2 CLIMATE
The feeling of climate is rather individual and depends on physical conditions, types of activity, clothing, etc. but there are some general rules. Climate requirements on boats are provided by air-conditioning and heating
©2012: The Royal Institution of Naval Architects C-47
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