15-02-2016, 23:32
Ho dato un occhiata alle pagine web di Mantus ,Rocna,Fortress,Delta.
A parte l'incredibile tenuta in confronto al peso della Fortress ( cmq sembra utilizzata come seconda ancora di solito), Delta mi sembra che sottostimi un po' l'ancora da adottare ( 20kg per un 45 ft senza indicare il vento sopportabile)
Mantus e Rocna più seriamente per 50 nodi indicano ancore tra i 25 e i 34 kg.
Quindi per tenere molto vento, diciamo piu' di 40 nodi ci vuole un ancora tecnologica e pesante . ( ovviamente anche catena e giunti più che adeguati) .
Interessante questo commento della Rocna:
There is a tendency amongst anchor manufacturers to recommend sizes smaller than those really required. They invariably suggest very optimistic sizes for impractically light conditions. For example, a certain world-renowned name-brand advises the use of a 20 kg (44 lb) anchor on a heavy cruising yacht of LOA up to 14.8m (49'). This recommendation is far too light when the tested performance of this particular anchor is considered in conjunction with the forces this boat size may be expected to generate. Another brand states that a working anchor should hold "up to 30 knots of wind". In our view, an upper limit of 30 knots wind would make the anchor a very light-weight temporary hook which has no place as the primary bower on any vessel.
The tendency to this misleading advice exists simply because it is thought to make the anchor in question look better in the eyes of the customer – either better performing than the competition, or cheaper, or both. Additionally, a manufacturer producing a number of different 'styles' of anchors, commonly copies, may feel the need to 'position' a particular design in such a way so as to rank it 'correctly'. This distorted logic results in compounded errors and unrealistic sizing.
A parte l'incredibile tenuta in confronto al peso della Fortress ( cmq sembra utilizzata come seconda ancora di solito), Delta mi sembra che sottostimi un po' l'ancora da adottare ( 20kg per un 45 ft senza indicare il vento sopportabile)
Mantus e Rocna più seriamente per 50 nodi indicano ancore tra i 25 e i 34 kg.
Quindi per tenere molto vento, diciamo piu' di 40 nodi ci vuole un ancora tecnologica e pesante . ( ovviamente anche catena e giunti più che adeguati) .
Interessante questo commento della Rocna:
There is a tendency amongst anchor manufacturers to recommend sizes smaller than those really required. They invariably suggest very optimistic sizes for impractically light conditions. For example, a certain world-renowned name-brand advises the use of a 20 kg (44 lb) anchor on a heavy cruising yacht of LOA up to 14.8m (49'). This recommendation is far too light when the tested performance of this particular anchor is considered in conjunction with the forces this boat size may be expected to generate. Another brand states that a working anchor should hold "up to 30 knots of wind". In our view, an upper limit of 30 knots wind would make the anchor a very light-weight temporary hook which has no place as the primary bower on any vessel.
The tendency to this misleading advice exists simply because it is thought to make the anchor in question look better in the eyes of the customer – either better performing than the competition, or cheaper, or both. Additionally, a manufacturer producing a number of different 'styles' of anchors, commonly copies, may feel the need to 'position' a particular design in such a way so as to rank it 'correctly'. This distorted logic results in compounded errors and unrealistic sizing.
