Fishing Vesels stability

Discussion in 'Stability' started by Guillermo, Mar 8, 2008.

  1. Guillermo
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    Guillermo Ingeniero Naval

    Thank you for your kind offering.
    Just give me some time to have the program ready and then you tell him. We will be honoured if he wants to attend. The main focus of the Seminar will not be talking technical stability issues, but how to tell fishermen about it and how to give them useful information to be able to evaluate at sea the stability condition of the vessel.

    Cheers.
     
  2. Ad Hoc
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    Ad Hoc Naval Architect

    Guillermo

    Ok, i'll wait until more info is at hand. He is also very busy and may not respond in time or even have time/funds too. But one can ask...no harm in trying.
     
  3. Guillermo
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    Guillermo Ingeniero Naval

    All,
    Here you have the final program for the "crews and stability" seminar in Vigo.
    Final data has changed to september the 16th, due to the conference room availability.
    I'll be most happy if some of you could attend or then tell other interested people about it.
    As this may prove very difficult to achieve, after the seminar I'm going to prepare a CD with all papers and presentations and probably we'll post them at our Association's web pages.
    I'll keep you informed.

    Cheers.
     

    Attached Files:

  4. Ad Hoc
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    Ad Hoc Naval Architect

    Guillermo

    Thanks for the update. I'll ask my Prof friend if he is aware of this.
     
  5. Guillermo
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    Guillermo Ingeniero Naval

    Seminar took place yesterday and rose a lot of interest.
    I'll soon post a link to the web pages from where papers and presentations may be downloaded.

    Cheers.
     
  6. helen07
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    helen07 Junior Member

    My husband who was a trawlerman has fished just about every type of vessel mentioned has asked me to reply on his behalf .

    He says though the rule breaker design hasn't really changed the seaworthiness of boats but it has changed our attitude to the sea . The oldest boat he worked was a 1935 plank on frame construction , originally a seiner converted to scallop dregde and queenie fishing . A mere 50ft in length this boat was reasonably comfortable up to force 8 winds but had a tendancy to roll terribly . The same goes for all plank on frame traditional boats but add length and thats when the trouble starts . A similar boat built in 1946 and 65ft in length had a tendancy in heavy seas to lift her keel out of the water only to slam back down with a bone juddering jolt that made one fear she would spring a plank and the same goes for all of that design .
    The power available in traditional boats was severly lacking and so design was aimed at giving the smoothest cut through water allowing the sheer weight of the boat to give the best achievable steady speed (a must i fishing)

    Modern boats on the other hand have deep drafts , high rails and huge engines . This allows the weight to be carried deeper and to be dispersed over a far greater volume of water , the length of the boat is dictated only by the neccesary working deck space . This does not in anyway alter the sea worthiness of the boat , in fact it must improve buoyancy . To simplify - a canoe will offer greater efficiency through water than a barrel , but if you place a stack of bricks in a canoe it is likely to capsize whereas a barrel will simply bob like a cork .
    And thats why the rule beating design works , power is readily available nowadays so bob like a cork and rely on brute force to keep you moving .

    Incidentally the rules said to be broken are worthless anyway a smaller boat with a bigger engine will pull a larger spread of gear than a larger boat with a smaller engine thus the Smith family who have fished for centuries in hand me down boats are denied fishing rights because their boat is 3ft too long despite the fact the boat cannot possibly benefit from the extra length as a lack of power means they cannot pull even half the weight of the Jones familys new boat .

    Owners of beautiful traditional boats have been forced to cut off the stem to meet regulations , in every manner that matters the boat is self restricted to comply with the rules but that bit of wood would see them bankrupt if it were not removed . Forcing incabable boats further out to sea is the danger nowadays and as a result of this my husband has phoned home on 3 seperate occasions to apologise because he did not expect to survive . This has never happened on a rule beater design .
     
  7. Ad Hoc
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    Ad Hoc Naval Architect

    helen

    I do sympathise, and your husband does indeed work in a very harsh environment, one in which he faces danger, very real danger every day. For that one can only admire his courage. However, i should point out that
    "..Forcing incabable boats further out to sea is the danger nowadays.."
    no one is being forced by the regulatory bodies to go further out to sea. The lack of catch close to shore is the reason one is going further out to sea. That is the choice/decision by the skipper, to earn money, not as a result of legislation.

    The stability and seaworthiness of boats is far more complex and interlinked with each other. Many factors affect both, one of which is money. I am in no way a fan of endless legislation, i fight it tooth and nail myself, (I am a naval architect) however, one must rationalise what the concern really is and separate the all too obvious emotive argument from the logical one.

    An acquaintance of mine is a Prof on the IMO stability committee and he deals and does endless research on seiners and their stability; to improve their risk of capsizing. All the points you raised need debating rationally and to establish where the concerns lay and if the concerns have already been addressed.

    To do so, one needs data and facts. Without such there will be no progress to the satisfaction of anyone. Legislation is ostensibly reactive, it is generally "lagging behind" the current status quo. As such it just reacts to factual evidence and tries to prevent the same occurring. Hence facts are needed to build a case, any case, to indicate what/where if any aspect of the legislation is wrong.

    I am, for my sins, on Lloyd's Registers Technical Committee. We review rules old and new from in service experience to ascertain if they need changing. More often than not the change boils down to one of two issues:
    1)Rule inadequate, hence a reworking to reflect the 'current' thinking, based upon new evidence
    2) Poor design/workmanship/seamanship. No accounting of legislation can cover all these.

    Hence any argument about "this design" or "this rule" is wrong, one needs to establish what is really wrong and why.....if at all.

    Rules are there for a reason....but, is the reason still valid, or, has the rule just been poorly implemented that causes possible negligence or a cascade of events that leads to such, inadvertently. (ie establishing the chain of events that causes such accidents).

    Consequently, none of this is a one liner answer, and cannot be simplified into barrels bobbing up and down compared to a canoe, to justify a position or stance as a basis of inadequacy or ridicule!
     
  8. peter radclyffe
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    peter radclyffe Senior Member

    ad hoc , youve just trashed one mans 50 years experience
    is there anything you think you dont know
    your so arrogant
     
  9. Ad Hoc
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    Ad Hoc Naval Architect

    peter
    care to explain what you mean?
     
  10. wardd
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    wardd Senior Member

    experience without knowledge can be a dangerous thing and knowledge without experience can be next to useless
     
  11. helen07
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    helen07 Junior Member

    reply

    Ad Hoc the rule makers arrogantly and wrongly assume that the larger the boat the greater the fishing capacitity . Also it is arrogantly assumed that fishermen risk their lives daily in greedy pursuit of huge profits , again this is wrong .

    The current rules mean a fisherman with the money to buy a boat of the new design can if he chooses fish right up to the shoreline with gear acceptable to the rules , he can also if he chooses go maybe 40 miles or more out to sea and increase the size of his gear as the rules allow . His engine is likely to give him steaming speed under any weather conditions of around a 14 knots so the risk of poor weather can be calculated against travelling time to a safe haven .

    The vast majority of boats in the British fishing fleet are of the traditional design and few have suitably powered engines to make up an 8 knots steaming speed in favourable weather . However this is the platform on which a mans life revolves . He cannot due to the design of his boat and the rules fish inshore , he cannot due to the design of his boat and his limited power increase the size of his gear while fishing offshore .
    Thus he has 2 choices , either he puts himself and his crew in mortal danger , putting his trust in God alone , to catch just enough to cover fuel bills and hopefully pay the men a wage , though under the current rules he can never hope to show a profit that might encourage a bank to finance the purchase of a new boat . Or he can accept bankruptcy .

    My husband recalls an amusing incident when a safety inspector was not happy with a friends roll test results , (for those who don't know they tie a rope to the highest mast on the boat , attempt to pull the boat over , let the rope go and see how long the boat takes to come to rest !) . The Skipper got very angry as he had fished the boat for nearly 20 years . He took the inspector by the scruff of the neck dragged him aboard and steamed out to sea in a force nine gale . He arrived back maybe 2 hours later with a very green looking inspector and oddly enough all questions of stability were forgotten and no further action was taken .

    Fishermen are hard men they work with the sea , not at sea , for many it is the only life they know and current legislation is not helping them or fish stocks at all .

    Obviously real data and calculations are absolutely neccesary and none are offered in my posts but all data must be compared against what you call emotional views or else the data is worthless in reality .

    The second world war might be reduced to a simple mathematical sheet of calculations but does this in anyway reduce the profound impact the war had on the world and the people in it .

    The canoe and the barrel example is nothing more than a blatantly obvious observation .
     
  12. Ad Hoc
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    Ad Hoc Naval Architect

    Helen
    I'm not sure how you equate larger vessel with larger capacity and that the 'rule makers' assume as such; why must the boat be larger, for example? Who says you MUST have a larger boat. This may well be the designer squeezing out as much as possible from the rule that is allowable. Designers are very good at pushing rules to the limits, whether they make sense or not.

    May I ask, what size fishing vessel your husbands boat is (is it possible to provide some basic data), and what rules/regulations his boat must comply with, and if you can answer why, too?

    The why is important, as this defines the MO (Modus Operandi) for the whole boat, as such the rationale behind the designers thinking. Is the MO the same as the SOR - statement of requirements, that the owner wants, as the two can often be conflicting.

    I just wish to avoid the all too obvious emotive and hence polemic pathos arguments, as already noted by Peter above, without ascertaining any kind of facts first.

    Anecdotes are for those that wish to engage in heated personal debates, since i can provide many of my own. But they contribute nothing to the real concerns you have, other than my own personal story, as a counter.

    You must appreciate i am in no way belittling anything, i am just trying to understand your concerns to rationalise them in terms of how they fit into the law/regulations that exist.
     
  13. helen07
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    helen07 Junior Member

    Ad Hoc i appreciate your want for reasoned discussion rather than just anecdotal nonsense and i had no intention of turning this into a debate . I will try to make my point as specific as possible here .

    A 65ft plank on frame traditional build powered by a 110 Gardener and rigged for dregding cannot possibly pull more than 6 dregdgers aside in even the most favourable conditions . Poor weather means a dredge a side must be removed thus lowering earning capacity . The boat was built before the current rules were in place and it has been handed from father to son as is tradition . Under the current rules this boat must fish offshore for no other reason than it is too long . The son therefore cannot make a living without taking undue risks as time at sea is his only option if he is to stay in business . His earning capacity is so reduced that he cannot hope to finance a new boat and so a family that can lay claim to four generations in the fishing industry is lost as a boat can only remain sea worthy for so long .

    A steel boat specifically designed to beat the current rules with regards to length can fish wherever it wants , it can pull maybe 10 dredges a side with ease under any weather conditions and it costs upwards of £350,000 , a price tag most traditional fishermen cannot hope to meet .

    Rule makers fail to see that most fishermen want nothing more than to own a boat on which can make a living . A true fisherman will return to the same tiny patch of ground annually , fishing it for maybe 2 weeks until the catch shows signs of waning , he will then up gear and move on thus ensuring a productive 2 weeks the following year and perhaps for all the years to come from the same ground .

    To return to the question of stability , the new shorter boats do indeed bob like corks and the old idea of hulls designed to cut an easy path through water has been laid to waste by engines offering huge power . Though i can offer no statistics to prove my point experience tells me that the newer boats are extremely unlikely to dip there rails below water level (a common occurance on older boats) . As a working platform the newer design is far more unpredictable compared to old boats because while bobbing like a cork the seas motion seems unrelated to the boats whereas on the old design a boat will surf with the wash and dip with the troth rising violently when it meets a wave in a very predictable fashion to the experienced .

    I truthfully don't think i can add anything useful to this forum other than to suggest that all statistics and data are completely void once a boat puts it's gear in the water , the variables a fishing boat inevitably encounters are so complex that they deny calculation .

    If i were asked for a suggestion to make the new design safer i'd say greater thought should be given to how fast a submersed deck can clear itself of water . Metre high rails are now the norm yet a single scupper port and starboard in the after section rail is often the only drainage available and if a boat comes fast in heavy seas this could prove fatal in a matter of seconds .
     
  14. baeckmo
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    baeckmo Hydrodynamics

    Just a reflection here; talking about technical rules for the vessel design and safety is one thing. Talking about the rules that regulate who is fishing where, and with what capacity and so on is a completely different story. I believe that maybe Helen and Ad Hoc are not talking about the same set of rules.

    The later set of rules, today often with the aim of limiting the exploitation of a specific stock, will have direct impact on the technical design and ultimately on the ergonomy and safety for the crews. They are enviropolitical "catch limiters", BUT, they are generally not setting technical standards, other than for some random variables expected to direct the catching capacity in one way or another.

    They do, however sometimes lead to rule cheating designs that are problematic in terms of seaworthiness, fuel economy and crew comfort/safety. When these designs are confronted with, and falling short of the requirements of the (adequate) technical rules, it is all too easy to blame the tech rules for being tricky and the root of all evil.

    It is the ever changing catch limiting rules that we see as problematic for the fishing society here. A good vessel may be outruled overnight for a certain fishing and the fisherman going bust without the bureaucrats giving a d..n. The technical rules, on the other hand are based on physical laws that have not changed much since the first man using a floating log for transport.
     

  15. Ad Hoc
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    Ad Hoc Naval Architect

    Helen
    Thank you for your reply, and this forum is whatever we wish it to be, so no need to feel that one is hijacking or 'hmm, not sure where to ask this' etc. Vent and lets see where the topic/debate goes.....that is the point of a forum.

    You have, as i suspected lead into the area which i felt was the real concern. This has been preempted and pointed out by baeckmo :) (i have to get up pretty early in the morning to catch him out..hehehe).

    Since the argument is thus:

    If your husband and all those other fishermen, could jump into their fishing boats, and happily catch endless supplies of fish from say 5m or 50m from shore, would this satisfy you/them? Clearly the answer is yes.

    Today, in the waters that your husband plys, can he earn a good living by fishing some 50m off the beach...no.

    Why, centuries of fishing and, the heated debate of EU rules allowing 'other's nations access to the UK fishing waters etc etc.....another debate!

    However, the fish stocks have been depleted and as such to obtain a catch that would be considered "good" or "pays my mortgage" one cannot get until going much further out to sea.

    As soon as the area of operation changes, from say 50m to 50nm off shore, the design and safety and all the other aspects of design and operation change, considerably.

    Other commercial boats which were built some 50 years ago, for whatever function, by today's standards would also be hard pushed to pass any existing legislation.

    A good more recent example is the fast ferry sector. 15 years ago, hovercraft were Classed not by the MCA but by the CAA. It was considered an aircraft. The 'rules' changed with the introduction of the IMO High speed craft code. Hovercraft are now Classed in the traditional way, ie by a classification society for its strength etc and a flag state (MCA in the UKs case) for its safety, not the CAA.

    Almost all the existing older hovercraft cannot pass the current legislation to which they must comply. These require a redesign. Owing to their unique nature, they were given dispensation for many aspects and also older vessels allowed to run until they 'retire' owing to these major changes (with caveats!).

    Older fast ferries, did not require sprinkler systems or to carry a rescue craft etc, now they do.

    Rules constantly evolve and chnage and older vessels shall always be left behind.

    The situation you are in is slightly different since the same waters in which the previous generation fished, is no longer possible. So the constant, ie the same patch, has become a variable. This leads to different solutions and restrictions.

    It is sadly, more a case of over fishing, quotas and EU beaurocrats that are preventing that which has existing before, not the technical rules of fish boat design.

    Finally, as for:
    "..If i were asked for a suggestion to make the new design safer i'd say greater thought should be given to how fast a submersed deck can clear itself of water . Metre high rails are now the norm yet a single scupper port and starboard in the after section rail is often the only drainage available and if a boat comes fast in heavy seas this could prove fatal in a matter of seconds.."

    Rules exist for the areas of the freeing ports that must be in place to allow green/excess water to clear itself. The rule is thus:

    Area = 0.7 + 0.035l
    where l = length of bulwark.
     
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