J/70 Owner Guide
Page
© Copyright 2013, J Boats, Inc. All Rights Reserved
6
Definitions of CE design categories:
A OCEAN: Designed for extended voyages where conditions may exceed wind force 8 (Beaufort scale) and
significant wave heights of 4 m and above but excluding abnormal conditions, and vessels largely self-‐
sufficient.
B OFFSHORE: Designed for offshore voyages where conditions up to, and including wind force 8 and
significant wave heights up to, and including, 4 m may be experienced.
C INSHORE: Designed for voyages in coastal waters, large bays, estuaries, lakes and rivers where
conditions up to, and including, wind force 6 and significant wave heights up to, and including, 2 m
may be experienced.
D SHELTERED WATERS: Designed for voyages on sheltered coastal waters, small bays, small lakes, rivers
and canals when conditions up to, and including, wind force 4 and significant wave heights up to, and
including, 0,3 m may be experienced, with occasional waves of 0,5 m maximum height, for example from
passing vessels.
NOTE: The significant wave height is the mean height of the highest one third of the waves, which
approximately corresponds to the wave height estimated by an experienced observer. Some waves will be
double this height.
J/70 Recommended Loading
Maximum Crew = 6 People at 75 kg (165 lbs.) each.
Manufacturer's Recommended Maximum Total Load = 530 kg (1,168 lbs.) -‐ Includes crew
This assessment has been made assuming that all standard equipment is aboard and that the boat in light
craft condition has a mass of 794 kg (1750 lbs.). This recommended maximum load takes into account the
mass of the following:
a)
The number of persons onboard: Where children are carried as part of the crew the maximum
number of persons may be exceeded provided that each child's mass does not surpass a limit of 37.5
kg (83 lbs.) and the total persons mass (75 kg) is not exceeded.
b)
basic equipment mass of (LH-‐2.5)^2 considered not to be less than 10kg.
c)
stores and cargo (if any), dry provisions, consumable liquids [not covered by d) or e)], and
miscellaneous equipment not included in the light craft mass or in b);
d)
consumable liquids (fresh water, fuel) in portable tanks filled to the maximum capacity;
e)
consumable liquids (fresh water, fuel) in permanently installed tanks filled to the maximum
capacity;
f)
a life raft or dinghy when intended to be carried.
This boat has been assessed using the Stability Index (STIX), which is a measure of the overall stability safety
and considers the effects of boat length, displacement, hull proportions, stability characteristics and
resistance to down flooding. This assessment has yielded the following data:
J/70 Mass in Minimum Operating Condition (mMOC): STIX = 22.53
Angle of Vanishing Stability = 122 degrees
J/70 Mass in Loaded Displacement Condition (mLDC): STIX = 18.20
Angle of Vanishing Stability = 107 degrees
