Stability and Freeboard
MGN 280 is a set of rules for vessels which proceed to sea, so this does not apply. However for comparison it is (200mm for 7m vessels 400mm for 18m vessels).
MCA (Maritime & Coastguard Agency) / AINA (Association of Inland Navigation Authorities) Inland Waters Small Passenger Boat Code is a Code of Practice for small commercial vessels operating in A,B,C & D waters which do not carry more than 12 passengers, do not carry cargo and do not go to sea.
All vessels should comply with the freeboard requirements given in Annex 9.
2.1
IN CATEGORY A and B WATERS, all vessels
operating in category A waters, or decked vessels operating in category B waters, should have a minimum freeboard to deck edge or gunwale of 250mm around the periphery of the vessel in the most onerous loading condition. For open vessels operating in Category B waters, this requirement should be increased to 400mm if they are unable to pass the swamp test as detailed in Annex 8 Section 1.3.
IN CATEGORY C and D WATERS: Minimum freeboard to downflooding for vessels whose stability has not been assessed in conjunction with ISO 12217.
1.
In the case of a vessel with a continuous watertight weather deck in accordance with:
6.1 Decked vessels
(See definitions in annex 2). 6.1.1 In a decked vessel, which complies with the freeboard provisions of Section 12 and Annex 9 of this Code, efficient provision is to be made to clear the deck of water which may be taken onboard. Where water may get trapped, the vessel should have a minimum of two efficient freeing ports – one fitted port and one starboard. 6.1.2 These ports should each have a clear area of: CATEGORY A & B CATEGORY C CATEGORY D 65sq cm, 135sq cm, 225sq cm.
These figures are based on maximum expected wave heights. Smaller ports may be suitable in a vessel having only small side deck areas, in which water can be trapped, the reduced area being based on the volume of water that is likely to become so trapped.
In the case of a vessel with a continuous watertight weather deck which is neither stepped nor recessed or raised, not in compliance with 6.1.2 above should have a freeboard to downflooding of not less than: - Category C 360 mm for vessels of 7 metres in length or under and not less than 630 mm for vessels of 18 metres in length or over.
- Category D 600 mm for vessels of 7 metres in length or under and not less than 1050 mm for vessels of 18 metres in length or over.
2.
In the case of a vessel with a continuous watertight weather deck, it must have a freeboard to deck measured down from the lowest point of the deck of not less than:
- Category C 120 mm for vessels of 7 metres in length or under, and not less than 240 mm for vessels of 18 metres in length or over.
- Category D 200 mm for vessels of 7 metres in length or under, and not less than 400 mm for vessels of 18 metres in length or over.
3.
in the case of an open boat, it should have a clear height of side, eg. the distance between the waterline and the lowest point of the gunwale* of not less than:
- Category C 240mm for vessels 7 metres in length or under, and not less than 480mm for vessels 18 metres in length or over.
- Category D 400mm for vessels 7 metres in length or under, and not less than 800mm for vessels 18 metres in length or over.
For a vessel of intermediate length, the freeboard should be determined by linear interpolation.
4.
For vessels complying with points 1 and 2 above, the freeboard to deck edge should, in general, be not less than 50% of the required freeboard to downflooding.
Freeboard Measurement 1.2
The boat should be tested with the maximum number of persons (passengers and crew) onboard, in the fully loaded condition i.e. with full tanks, full stores etc. The persons and equipment should be positioned as to represent the “in service” condition of the boat. The boat should be at its normal working trim and have no angle of heel. If so required, each person may be represented by a weight of 75kg. Arrangements should be made in order to allow a person outside of the vessel to take all measurements.
British Marine Inland Waterways Small Passenger Boat Code Stability & Freeboard Standards
1. 2.
The angle of heel does not exceed 7 degrees, and
In the case of a vessel with a watertight weather deck extending from stem to stern, the freeboard to downflooding is not less than 100 mm for MCA Category A waters or 175mm for MCA Category B waters. (Note: MCA Categories A & B are generally equivalent to RCR Category D) and additionally, the freeboard to deck is not less than 75mm at any point.
3.
The angle of heel may exceed 7 degrees, but should not exceed 10 degrees, if the least freeboard to downflooding in the heeled condition is in accordance with Section 3 of this Code for the upright condition.
102 | ISSUE 111 | MAR 2025 | THE REPORT
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132 |
Page 133 |
Page 134 |
Page 135 |
Page 136 |
Page 137 |
Page 138 |
Page 139 |
Page 140 |
Page 141 |
Page 142 |
Page 143 |
Page 144 |
Page 145 |
Page 146 |
Page 147 |
Page 148
