freeboard

[john d]

I'm in the process of designing a new build barge, and despite visits to the govt website, can't work out how to calculate the freeboard required to get the barge to cat B or C. Does anyone know how to work this out? My design is 50ft X 13'6" and will probably weigh about 25 tons.
Thanks!
John D

[Admin (Chris)]

Hi,

Try Mike Hickson of Goldwater Boats mike@goldwaterboats.force9.co.uk - www.goldwaterboats.force9.co.uk he is very helpful and built the Iron Dutchess shell for me, he should know, or will be able to find out for you.

Edit: Sadly no longer trading.

[Admin (Chris)]

I received this reply by email from Mike Hickson of Goldwater Boats.

CATEGORY A AND B ?? MOTOR VESSELS
ANNEX 9
FREEBOARD
1 General
For the purposes of this Section, where vessels are to operate in fresh water, the minimum freeboards defined within this Section are to be taken in the area of operation, as appropriate.
1.1 Where stability is assessed using any part of ISO 12217, freeboard is to be assigned using the appropriate part of that standard.
1.2 Annex 10 gives simple guidance on how to measure freeboard.
2 Motor Vessels
2.1 All vessels operating in Category A waters, or decked vessels operating in Category B waters, should have an 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.

CATEGORY C AND D ?? MOTOR VESSELS
ANNEX 9
FREEBOARD
1 General
For the purposes of this Section, where vessels are to operate in fresh water, the minimum freeboards defined within this Section are to be taken in the area of operation, as appropriate.
1.1 Where stability is assessed using any part of ISO 12217, freeboard is to be assigned using the appropriate part of that standard.1.2 Annex 10 gives simple guidance on how to measure freeboard.
2 Motor Vessels
2.2 IN CATEGORY C and D WATERS: Minimum freeboard to downflooding, for vessels whose stability has not been assessed in conjunction with ISO 12217 ??1 or 3, should be not less than that determined by the following provisions.
2.3 A vessel, other than an inflatable or rigid inflatable boat, or a boat covered by Section 2.2 of this Annex, when fully loaded with passengers and deadweight items to be carried (each person taken as 75kg) should be upright and:
1. in the case of a vessel with a continuous watertight weather deck in accordance with Section 6.1.2, which is neither stepped nor recessed or raised, have a freeboard to down flooding 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.
For a vessel of intermediate length the freeboard to down flooding should be determined by linear interpolation.
2. in the case of a vessel with a continuous watertight weather deck should have a freeboard to deck measured down from the lowest point of the well 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.
For a vessel of intermediate length, the freeboard should be determined by linear interpolation. The raised portion(s) of the watertight weather deck should extend across the full breadth of the vessel and the average freeboard to deck over the length of the vessel should comply with .4 below for a vessel with a continuous watertight weather deck.
3. in the case of an open boat, 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 clear height should be determined by linear interpolation.
*The clear height of the side should be measured to the top of the gunwale or capping, or to the top of the wash strake if one is fitted above the capping.
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 down flooding.

For anyone wanting their own copy, the .doc or .rtf files are attached for download.

[Admin (Chris)]

I also found this on the web,

All new boats built in Europe since 1998 must comply to the RCD (Recreational Craft Directive). Within this directive are 4 design categories. A, B, C and D.

The lowest cost barges, designed for predominantly canal use in the UK will likely be category 'D'. Most new built Replica Dutch barges are built to RCD Cat 'C' which is deemed suitable for wind speeds up to force 6 and significant wave height to 2m. A few barges are designed and built to Cat 'B' requirements.

When buying a new unfinished barge (eg. shell or sailaway), the builder must still categorise the boat, up to supplied level of build. Therefore you can buy a sailaway barge that conforms to RCD Cat 'B, C or D' requirements. But because it is unfinished, a full conformation certificate will not be issued, as, for example, a Cat 'C' barge must take into account anchoring capabilities, the electrical installation, gas installation, navigation lights, waste water discharge and have suitable fire extinguishers on board.

It would be very difficult for the normal DIY enthusiast to get a RCD certificate of compliance after they have completed their boat, but generally it seems that a 'compliance up to build', plus a Bo at Safety Scheme (BSS) certificate is deemed acceptable for most purposes, including insurance and navigation licences.

ESSENTIAL SAFETY REQUIREMENTS FOR THE DESIGN AND CONSTRUCTION OF RECREATIONAL CRAFT - 1. BOAT DESIGN CATEGORIES

Design category
Wind speed
Significant Wave height
Comments
 

? ? A ~ "Ocean"
Exceeding Beaufort 8
Exceeding 4 m
Very few Barges built
to this spec.
? ? ? ? B ~ "Offshore"
?? ?Up to force 8 inclusive
?? ?Up to and including? 4 m
?? ?Few Replica Dutch Barges
?? ?built to this category
?

?
? ? C - "Inshore"
Up to force 6 inclusive
Up to and including 2 m
Most Replica Dutch Barges
are built to this category
? ? ?? ?D - "Sheltered waters"
?? ?Up to force 4 inclusive
?? ?Up to and including? 0,5 m
?? ?All Narrowboats and most low
?? ?cost Broad Beam Barges
?

Significant wave height means the average height of the highest 1/3rd of the waves over a given period. Waves of double that height may occasionally be experienced.

The RCD Defines Design Category as:-

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.

The directive also states that:-

Craft in each Category must be designed and constructed to withstand these parameters in respect of stability, buoyancy, and other relevant essential requirements listed in Annex I, and to have good handling characteristics.

There are special criteria to be considered with Kit Boats, Sailaways, and boats fitted out from finished hulls whereby compliance has to be demonstrated and certified by the manufacturer to the extent of their involvement. (Partly Built Craft).

A few salient points from the directive are listed below:-

Depending on the design category, craft shall be designed to minimize the risks of falling overboard and to facilitate reboarding.

For motor boats, the main steering position shall give the operator, under normal conditions of use (speed and load), good all-round visibility.

The craft shall have sufficient stability and freeboard considering its design category according to section 1 and the manufacturer's maximum recommended load according to section 3.6.

Openings in hull, deck(s) and superstructure shall not impair the structural integrity of the craft or its weathertight integrity when closed.

Windows, portlights, doors and hatchcovers shall withstand the water pressure likely to be encountered in their specific position, as well as pointloads applied by the weight of persons moving on deck.

All craft shall be designed so as to minimize the risk of sinking. Particular attention should be paid where appropriate to:

cockpits and wells, which should be self-draining or have other means of keeping water out of the boat interior

ventilation fittings,

removal of water by pumps or other means.

All habitable multihull craft over 12 metres long shall be provided with viable means of escape in the event of inversion. All habitable craft shall be provided with viable means of escape in the event of fire.

All craft, taking into account their design category and their characteristics shall be fitted with one or more strong points or other means capable of safely accepting anchoring, mooring and towing loads.

The manufacturer shall ensure that the handling characteristics of the craft are satisfactory with the most powerful engine for which the boat is designed and constructed. For all recreational marine engines, the maximum rated engine power shall be declared in the owner's manual in accordance with the harmonized standard.

All inboard mounted engines shall be placed within an enclosure separated from living quarters and installed so as to minimize the risk of fires or spread of fires as well as hazards from toxic fumes, heat, noise or vibrations in the living quarters.

Engine parts and accessories that require frequent inspection and/or servicing shall be readily accessible.

The insulating materials inside engine spaces shall be non-combustible.

The engine compartment shall be ventilated. The dangerous ingress of water into the engine compartment through all inlets must be prevented.

Unless the engine is protected by a cover or its own enclosure, exposed moving or hot parts of the engine that could cause personal injury shall be effectively shielded.

Electrical systems shall be designed and installed so as to ensure proper operation of the craft under normal conditions of use and shall be such as to minimize risk of fire and electric shock.

Attention shall be paid to the provision of overload and short-circuit protection of all circuits, except engine starting circuits, supplied from batteries.

Ventilation shall be provided to prevent the accumulation of gases which might be emitted from batteries. Batteries shall be firmly secured and protected from ingress of water

Steering systems shall be designed, constructed and installed in order to allow the transmission of steering loads under foreseeable operating conditions.

Sailboat and single-engined inboard powered motor boats with remote-controlled rudder steering systems shall be provided with emergency means of steering the craft at reduced speed.

Gas systems for domestic use shall be of the vapour-withdrawal type and shall be designed and installed so as to avoid leaks and the risk of explosion and be capable of being tested for leaks. Materials and components shall be suitable for the specific gas used to withstand the stresses and exposures found in the marine environment.

Each appliance shall be equipped with a flame failure device effective on all burners. Each gas-consuming appliance must be supplied by a separate branch of the distribution system, and each appliance must be controlled by a separate closing device. Adequate ventilation must be provided to prevent hazards from leaks and products of combustion.

All craft with a permanently installed gas system shall be fitted with an enclosure to contain all gas cylinders. The enclosure shall be separated from the living quarters, accessible only from the outside and ventilated to the outside so that any escaping gas drains overboard. Any permanent gas system shall be tested after installation.

The type of equipment installed and the layout of the craft shall take account of the risk and spread of fire. Special attention shall be paid to the surroundings of open flame devices, hot areas or engines and auxiliary machines, oil and fuel overflows, uncovered oil and fuel pipes and avoiding electrical wiring above hot areas of machines.

Craft shall be supplied with fire-fighting equipment appropriate to the fire hazard. Petrol engine enclosures shall be protected by a fire extinguishing system that avoids the need to open the enclosure in the event of fire. Where fitted, portable fire extinguishers shall be readily accessible and one shall be so positioned that it can easily be reached from the main steering position of the craft.

For annexes and further information see the full directive at:-?

http://http://www.hmso.gov.uk/si/si1996/Uksi_19961353_en_1.htm

[john d]

Chris
Thanks very much...its much less than I thought (I was allowing for a meter which, with an airdraft trying to squidge under the canal du midi bridges, meant a dropped cabin floor and an 18" bulwark) so many thanks again.
I note that the Iron Duchess is a Branson design with drop down wheelhouse. I'm trying to design something for europe that doesn't need a drop down, since we hope to have the galley/dining area with the helm in an 'up' cabin, hence the problem.
Anyway thanks... excellent site and v. useful response.
John

[Admin (Chris)]

I'm trying to design something for Europe that doesn't need a drop down, since we hope to have the galley/dining area with the helm in an 'up' cabin, hence the problem.

Hi,

Glad the info helped, but have you included line of sight in your calculations of the wheelhouse? If you drop the wheelhouse floor you will decrease your line of sight angle over the bows, and there are specifications as to how far from the bows you can see the water to get your category certification.? I'll look up and post the spec' if you like?

Also you have the problems of getting your design tested for stability and safe loading etc before category certification can be achieved, this can be very expensive. If you intend marketing your design then the expense can be recouped, but if it's just a one off build for you I'd find out how much it is going to cost.  It all has to be done in stages as the boat is built so the tester can see the construction meets the required regs'.

[john d]

Chris...
maybe I should define 'design'. For the last two years we have been daydreaming our ideal boat, and all this is part of that research. I love the traditional look of the barges, but feel that they are designed for the rain, not the Med. At some stage, my sketches, both interior and exterior, will be submitted to a 'real' designer (I've been in touch already with Branson and Wolstenholme and I expect it will be one of the two) to turn this dream into a working reality. I am really just dabbling here, but I do enjoy the learning experience and the time spent tuning my drawings in view of what I learn.
My current design looks as though sight lines will be fine... I drew out the sections and profiles and line of sight over bows 5'9" high seems fine; although I have not drawn it out exactly eye level from the interior helm would be approx 2'9" above the height of the bow, obviously far more from the outside steering position on top of the rear cabin roof (is that a loophole?). I'm still not sure which RCD to go for and may end up with a 'B' hull for strength, but overall 'C' to keep costs in check. In reality we would be very unlikely to venture beyond the estuaries (sea sick partner) but I am a belt and braces sort of person when safety is the issue. Anyhow,
many thanks for your continued response.

[Admin (Chris)]

I just received this from Mike Hickson of Goldwater Boats, as you have been in touch with both Branson & Wolstenholme you probably know this already.

Re barge design,

If a customer wishes a full steel wheelhouse on a Branson design, this can be done with minimum cost, at the builders and without need for redesign.

Wolstenholme? already has a fixed wheelhouse design. Which we can build

Fit out if in the UK, has to be done in areas with no bridges, because I understand across Europe Fold down is not required.

Branson designs if well Built are in RCD class C but can be in B.
Wolstenholme is in class B.