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Thread: COLREGs vessel length definition

  1. #1

    Question COLREGs vessel length definition

    I have always assumed the "length overall" defined in the COLREGs would mean overall length of the hull (excluding e.g. bowsprit, mizzen parts, etc.). However, the following site has a different view that made me confused.

    http://sailskills.co.uk/colregs/Sail...length-oa.html

    Where can we find the legitimate definition of "length overall" referred to in the COLREGs? There are several small sailing craft that are on either side of the 7 m or 12 m threshold depending on how you measure their length.

  2. #2
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    Default Re: COLREGs vessel length definition

    Rule 3 (j) says "The words “length” and “breadth” of a vessel mean her length overall and greatest breadth."

    The linked illustration shows this. Not much room for argument. Some might want to discount the added length of an outboard motor or rudder or overhanging boom or bow sprint. Good luck with that.

    But a swung out boom when you're sailing off the wind does not add to your official beam. It does add to your practical beam, as anyone who has sailed a Cape Cod Catboat knows full well.

  3. #3

    Default Re: COLREGs vessel length definition

    Seems Finland and UK has the same registration practice when it's about boat length. My concern here isn't about navigation lights but about the new Finnish Water Transportation Act (Vesiliikennelaki 782/2019) which entered in force in June. One of the sections (15§) says in a nutshell that a slow water craft under 7 m must stay out of the way of vessels over 12 m on common waterways, although the bigger craft must still do their utmost to avoid a collision. As the definition of length in that chapter conforms with that of the COLREGs (according to definitions in 3§) there seems to be a kind of "loophole".

    So, if you had a boat like Vivier's lug yawl rigged Ebihen 16 or Welsford's Pathfinder you would have a lively dinghy with a short waterline but which would still be juridically considered as a watercraft longer than 7 m, thanks to the overhanging parts of the rig.

    The practical consequences of the new law are probably quite minuscule as all craft are required to have proper lookout and speed to avoid a collision. Still, when two sailboats of the different sizes are on crossing paths you better be aware of the exceptions to the COLREG rules.
    Last edited by Timo8188; 07-30-2020 at 06:25 AM.

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    Default Re: COLREGs vessel length definition

    As an aside, I've always wondered why larger craft are required to have brighter running lights than smaller ones. Seems as if it should be the other way around.

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    Default Re: COLREGs vessel length definition

    This is non-official, and straight from my fevered memory, so take it for what THAT is worth...

    I deal a lot with various definitions of LOA: tonnage measurement, classification societies, fisheries regulations, and occasionally yacht racing rules. All have sometimes differing and often conflicting definitions. However, in dealing with COLREGS I would defer to the definitions from my naval architecture training:

    LWL - length of the hull at the static water line

    LOD - length of the hull as measured on centreline from the edge of the deck where the deck intersects the toerail or builwark to the edge of the deck where the deck intersects the stem

    LOA - length of the hull on centreline from the outboard uppermost edge of the transom or sternpost to the outboard uppermost edge of the stem or any permanently fixed bow structure

    Sparred Length - length measured from the aftermost extremity of all ship's structure, including booms, boomkins, davits, etc., to the foremost extremity of all ship's fixed or portable structures, including bowsprits, bow platforms, etc.
    Hope for the best, but plan for the worst.

  6. #6

    Default Re: COLREGs vessel length definition

    Quote Originally Posted by skaraborgcraft View Post
    How is the "common waterways" defined? Inland lakes, rivers and canals? Sounds more of a local regulation for inland waters, where international rules are already in place for coastal and offshore. Many narrow waterways will give rights to powered vessels over sail, where usually its the opposite. Commercial has taken precedence over leisure boats.
    My understanding is that a "common waterway" (yleinen kulkuväylä) is any waterway marked on the official Finnish nautical charts covering the territorial waters of Finland. The total length of those waterways is around 10,000 km on the lakes and 10,000 km on the coast.

  7. #7

    Question Re: COLREGs vessel length definition

    Quote Originally Posted by Ian McColgin View Post
    The linked illustration shows this. Not much room for argument.
    Quote Originally Posted by mmd View Post
    LOA - length of the hull on centreline from the outboard uppermost edge of the transom or sternpost to the outboard uppermost edge of the stem or any permanently fixed bow structure
    To me it looks we have two different interpretations represented here, as I feared. Does International Maritime Organization (IMO) have an exhaustive definition of the length?

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    Default Re: COLREGs vessel length definition

    To post #4, brighter lights on larger vessels because the larger vessels go faster, and need to be seen at a greater distance.

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    Default Re: COLREGs vessel length definition

    Quote Originally Posted by Timo8188 View Post
    To me it looks we have two different interpretations represented here, as I feared. Does International Maritime Organization (IMO) have an exhaustive definition of the length?

    The linked illo is from the pubishers of that website. It is not an official COLREGS image. So it is the web publisher's interpretation of the definition, which may be true. Or, not.

    Kevin

    Edit to add:

    In US and Canada ABYC standard S8;" Boat Measurement and Weight," states that the LOA is the centerline length including any molded in or integral appendages. I cannot cut and paste the reference as it is available to ABYC members only.

    Therefore a salboat with a clipper bow,or a 'glass powerboat with a molded in anchor pulpit, the LOA includes those features. If the boat has a bolted on swim platform or a reefable bow sprit, that is not included in the LOA.

    I cannot say if COLREGS uses this definition, but chances are they do, as many ABYC standards are also ANSI, NFPA, USCG, EU, ISO, UL etc standards.

    K
    Last edited by Breakaway; 07-31-2020 at 07:36 AM.
    There are two kinds of boaters: those who have run aground, and those who lie about it.

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    Default Re: COLREGs vessel length definition

    Quote Originally Posted by Timo8188 View Post
    Does International Maritime Organization (IMO) have an exhaustive definition of the length?
    I believe that as you are in Europe your vessels will have to comply with ISO boat regulations. Hull length is defined in ISO 8666. I do not have a copy of this document, unfortunately.

    However, the Norwegian Maritime Authority - a signatory to the IMO and compliant with ISO, defines LOA as:

    Introduction

    Maximum length, also referred to as length everywhere (loa), is used as a parameter in the regulations, and the Norwegian Maritime Directorate therefore wants a clear understanding of the concept of length. We have seen in some contexts that the concept of length is understood differently, which can lead to differential treatment and "erosion" of the regulations.

    What to measure in greatest length

    As a starting point, the maximum length shall be measured from the leading edge of the front part of the vessel to the aft edge of the aft part of the vessel when the vessel has been trimmed. Tires and bulwark cladding as well as all solid components must also be included regardless of the fastening method and material. Rudders, fittings and demountable details that do not affect the vessel's capacity can nevertheless be omitted from the measurement.

    Components to be omitted in the measurement of maximum length

    Weather-exposed / open parts of steering and propulsion arrangements / machinery, such as:
    . rudder
    . stern gears and outboard engines with mounting brackets
    Weather-exposed facilities and equipment that perform special functions, but which do not at the same time contribute to increasing capacities or protecting against the weather, such as:
    . loose fenders, and fenders that only lie around the end point of the hull
    . fittings, e.g. bow spindle and mezzanine boom
    . rig, e.g. bow spear
    Weather-exposed / open facilities whose sole function is to prevent people from falling overboard and which are not used for storage and storage, such as:
    . pulpit at both ends of the vessel
    . railings
    Weather-exposed / open facilities to ensure access for persons for necessary external maintenance or access to the sea, such as:
    . diving platforms
    . bathing platforms

    Components to be included in the measurement of maximum length (loa):

    hull
    deck
    bulwark
    fixed fender strip
    solid components that are attached to the hull, deck, deckhouse / superstructure or bulwark cladding
    structural elements that form part of the hull and that affect its design, capacities and properties (such as bow door, loading ramp, etc.,)
    construction elements for storing tools and / or tools regardless of the fastening method
    parts that act as hydrostatic or dynamic support when the vessel is at rest or en route
    volumes, such as bulb, attached «box» for mounting steering machinery, connected to hull, deck, bulwark cladding or deckhouse / superstructure, regardless of fastening method


    Please go to the NMA website and click on the link at the bottom of the page to see three pages of illustrations of the items described above: https://www.sdir.no/sjofart/regelver...ngde-pa-skip2/
    Hope for the best, but plan for the worst.

  11. #11

    Default Re: COLREGs vessel length definition

    Quote Originally Posted by mmd View Post
    I believe that as you are in Europe your vessels will have to comply with ISO boat regulations. Hull length is defined in ISO 8666. I do not have a copy of this document, unfortunately.
    Alright! There are an international regulations, we are expected to follow, but certain essential definitions of them are buried in another standard which is behind a paywall...

    Anyway, thanks for sharing the Norwegian definitions. It would be logical that they are compliant with the ISO standard, but who knows. Those rules seem to define LOA without the overhanging parts of the rig.

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    Default Re: COLREGs vessel length definition

    Quote Originally Posted by Timo8188 View Post
    Those rules seem to define LOA without the overhanging parts of the rig.
    In my opinion, that would be the correct definition of LOA.
    Hope for the best, but plan for the worst.

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    Default Re: COLREGs vessel length definition

    Quote Originally Posted by Dan McCosh View Post
    As an aside, I've always wondered why larger craft are required to have brighter running lights than smaller ones. Seems as if it should be the other way around.
    Quote Originally Posted by Boatsbgood View Post
    To post #4, brighter lights on larger vessels because the larger vessels go faster, and need to be seen at a greater distance.
    To piggyback Boats here, larger vessels are often less maneuverable and definitely take longer to stop - measured in miles for some of the really big boys out there. Being able to pick them on radar then visibly on the horizon makes sure you have plenty of time to avoid collision.

  14. #14

    Post Re: COLREGs vessel length definition

    I asked about the length overall (suurin pituus) from the Finnish Transport and Communications Agency. According to their interpretation the length overall of COLREGs is length of the watercraft with all the attached overhangs included. When sailing in local waters the official local interpretation should be the only interpretation which matters.

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    Default Re: COLREGs vessel length definition

    Timo, "... the official local interpretation should be the only interpretation which matters" is the salient phrase, except that I would change 'should be' to 'will be'. As for the part about '...all the attached overhangs' I would interpret that as all overhangs attached to the hull, which does not include spars.
    Hope for the best, but plan for the worst.

  16. #16

    Default Re: COLREGs vessel length definition

    Well, the key issue here is the word "interpretation" and that's why I consider "should be" as a better expression. If the agency had provided an exhaustive definition, it would be "will be". The final answer won't be known before there is a verdict. Nevertheless, lookout and speed are usually the primary things analysed in collision investigations.

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    Default Re: COLREGs vessel length definition

    I was merely offering a wry comment that to the local official, the local interpretation would be as if written in stone. Sometimes attempts at humour fail miserably when typed in an internet forum.
    Hope for the best, but plan for the worst.

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    Default Re: COLREGs vessel length definition

    This all reminds me of Harbour masters' and Marina management who have their own definitions too.
    I have usually relied in times of dispute, on the boat's ID papers. ..... 'Look , it says here, LOA x metres'.
    But I did have a run-in with a particularly bolshy official who said. 'OK we have laterally sliding pontoons. Moor the boat to the mainway , touching a pontoon . I'll slide the pontoon along till it touches your boat. we measure it., Ah, but , no, but. ..,,
    but then he was wanting to extract maximum revenue on a bts per metre scale. and one marina in the south will charge a 7m. boat as an 8 metre as it had a rope banana fender round the prow, another 10cm ...., and then it falls into the 8-11 metre class.... and so it goes.
    'C'est la vie' say the old folks it goes to show you never can tell

  19. #19

    Lightbulb Re: COLREGs vessel length definition

    Sometimes becoming a politician, who would correct all the famous laws, looks so alluring ... but then, how to fit in their mega yacht club in a minimalistic engineless small sailboat?

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    Default Re: COLREGs vessel length definition

    It used to be that Length over all was the measured length between perpendiculars. That is hang a plum bob from the stem and one from the top of the horn timber plus the thickness of the planking thereon and that was the over all length of a vessel. Marina owners got into the act and wanted more money for slip rental so it then became "Sparred Length" that was the criteria for length. Since that time all manner of bureaucracy has clouded the laws of measurement for vessels to the point that no one seems to know the correct answer any more. "Bright Star" is 28' between perpendiculars and always has been. But when push comes to shove in short term rent for a slip we can always remove the jigger boom.
    Jay

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    Default Re: COLREGs vessel length definition

    Quote Originally Posted by Jay Greer View Post
    It used to be that Length over all was the measured length between perpendiculars. That is hang a plum bob from the stem and one from the top of the horn timber plus the thickness of the planking thereon and that was the over all length of a vessel. Marina owners got into the act and wanted more money for slip rental so it then became "Sparred Length" that was the criteria for length. Since that time all manner of bureaucracy has clouded the laws of measurement for vessels to the point that no one seems to know the correct answer any more. "Bright Star" is 28' between perpendiculars and always has been. But when push comes to shove in short term rent for a slip we can always remove the jigger boom.
    Jay
    Yes, but...

    To a naval architect, perpendiculars are located where the DWL (LWL?) intersects the stem and sternpost/horn timber, thereby defining the LWL that needs to be divided into ten equal sections so that we can apply Simpson's Rules to calculate volume, displacement, WPA, LCB, LCF, coefficients, etc., etc. <grin>
    Hope for the best, but plan for the worst.

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