Best rough water hull you know.

Discussion in 'Powerboats' started by xarax, Aug 5, 2006.

  1. xarax

    xarax Previous Member

    Planing or semi-planing V-hulls have a hard time with short, steep waves. There have been various attemps to address the problem, often stated by many naval designers and owners as doomed to remain unsolved. Are there now, after all these years of modern powerboat development, any really satisfactory rough water planing or semi-planing boats that distance themelves from the rest ?
     
  2. SeaSpark
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    SeaSpark -

  3. CORMERAN
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    CORMERAN Junior Member

    Best rough water....

    To xarax.

    SeaSpark is on the right track.

    Nigel Irens is a pioneer in this area. His designs have PROVEN that there
    ARE ways to achieve good speed in rough water.

    However - this is a VERY sensitive issue in the marine design world.
    Especialy, people coming from a traditional European tradition.

    Whereas, Mr. Iren's inspiration comes more from the Pacific Island traditions
    - of the last 10,000 yrs. or so.

    More recently - a vessel called " Earth Race ", ( 40 knot, 80 ft. powered Trimaran) which recently docked in Vancouver, Can. - is showing very
    exceptional heavy weather performance.

    - In some respects, this boat is similer to craft that I have designed
    and built.
    - MUCH easier riding than the typical production planing boat.
    - So the excellent seakeeping of " Earth Race " is not a suprise to me.

    - Then there's the drug dealer's preferred marine transportation device.
    - As shown in the recent teen age movie " Miami Vice "

    Therefore, the answer to your question is:

    - Yes, there are ".....really satisfactory rough water planing or semi - planing
    boats that distance themselves from the rest."
    Quite a fair distance, in fact.

    Cheers !
     
  4. Ike
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    Ike Senior Member

    Best rough water planing hull? Coast Guard 30 foot Surf Rescue Boat. It has it's problems but it did the job. It and the 44 foot surf boat (not a planing hull) have been replaced by the 47 foot surf rescue boat (also a planing hull) and RHIBs. But in it's day it was the first planing hulled surf rescue boat
     
  5. xarax

    xarax Previous Member

    Surf rescue boat hulls

    Thank you Ike,
    Is there an essential difference between the hull lines of the 30 ft surf rescue boat and the hull lines of its succesor, the 47 ft boat ?
    These boats are remarquable, no question about that, but it seems to me that been able to climb 30 feet surf mountains on the one hand, and penetrate short, steep waves efficiently on the other, are quite different problems. Do the hulls of these rescue boats address both of them?
     
  6. Willallison
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    Willallison Senior Member

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  7. duluthboats
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    duluthboats Senior Dreamer

    To my inexperienced eye it looks like long and narrow is the way to go. The Irens designs so much so that they needed training wheels.

    Gary
     
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  8. Ike
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    Ike Senior Member

    XARAX;
    Basically the hull design is the same but there are some important differences. First place both of these boats have a deep vee aft fairing into a deep slightly rounded forefoot. Essentially they are the semi-planing type hull, but the chines only run about half way forward. They learned a lot from the 30 foot boat. The 30 was a single engine swinging a really big prop. The engine was amidships fore and aft (not a good place for a planing boat). These boats had a hook in the planing surface on the port side all the way aft to counteract the torque of the prop. They had some nasty habits, the worst was nose diving at certain speeds and laying over on the starboard side. This would throw the crew out of the boat if they weren't strapped in. But, they were quick, pretty good in the surf and rugged and a coxswain could be trained to anticipate the dive and avoid it.

    The 47 has basically the same lines, but has twin engines, placed farther aft, does about 25 knots. and doesn't nose dive. It is very rugged and has been through some really nasty stuff in real time ops. Of course it is self righting and will take a 360 and keep on going. Is it as tough as the old 44? Probably. But then the 44 could do only about 8 knots. The old 44 would pitch pole in a following sea if not handled by a really experienced coxswain. With the 47 you have enough power to out run the wave and even surf. Plus you can power up an oncoming wave as well. So in a following sea you can get on the back of a wave and stay there. The draw back is they carry a lot of electronic stuff and are bristling with antennas. All that above deck stuff disappears if they take a 360 and it's not easy on the stuff inside either. The crew has to wear survival suits and helmets and be strapped in. Otherwise when you get into the surf you'll lose them over the side (it's happened). For that matter last year one got lost in the surf in Oregon and the crew had to be rescued by helo. Strangely enough the boat survived and was salvaged with mostly water damage.
     
  9. xarax

    xarax Previous Member

    Thank you Ike,
    "...in a following sea you can get on the back of a wave and stay there."
    Remarquable ! Coast Guard made the right choice, I suppose, although the cost of about 1M$ each (for 150 identical boats) is remarquable, too....:)
     
  10. Ike
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    Ike Senior Member

    Yes, They are damned expensive, but then what's the price of a life? I spent 25 years in Boating Safety and believe me when I say that when putting together budget's they actually ask that question. Congressmen never actually come out and say it but when they consider the Coast Guard budget you can bet they have it in mind.

    (by the way for years the insurance industry used $500K, but now I think it's up above $1 mil, I've lost touch in the last few years)

    As for whether they made the right choice, I dunno? There were plenty of off the shelf designs available. Both those boats were inhouse designs. You want to know more detail about them talk to CDBarry.
     
  11. SeaSpark
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    SeaSpark -

    Lifeboats

    Our lifeboats are paid for by private gifts, the KNRM decided they want to operate without any attachment to the government for good American reasons. As far as i know all their boats are uninsured.


    http://www.knrm.nl/65reddingboten/20Type_Arie_Visser_(19_m.)/01Arie_Visser/

    edit:

    "arie visser" class lifeboats cost 1.200.000 euro

    displacement: 28 metric tonnes
    size: 18,80 x 6,10 m
    power: 2 x 1000 pk (735 kW)
    max speed: 35 knots
    capp.: 120 saved persons
    crew: 6
     
  12. xarax

    xarax Previous Member

    I am really sorry if I have not expressed myself clearly, Ike. Of course, a human life costs nothing, but nothing costs as much as a human life...What I had in mind was that, given the big total number of identical boats that, eventually, would be constructed in line, some 200 of them(?), the cost should have been lowered somehow, shouldn t it? And I guess that it might have been better statistically to build a double number of boats. each with half the cost, if this would have had help them to reach and save an endagered human life at a double number of places in half the time.
     
  13. Ike
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    Ike Senior Member

    First: doubling the production run doesn't halve the cost. It reduces it but not that much.

    Also That is why I made my comment about off the shelf designs being available. A lot of that cost could have been saved by using an existing design. Why didn't they? Most of the existing designs are foreign. Is that a bad thing? No. The Coast Guards 110 foot patrol boats are a korean design, adapted for our use. But, someone at the HQ level felt they needed to start with a clean sheet of paper and design it from the ground up.

    Time will tell. Plus that some of that cost is due to stuff added since 9/11, for national security purposes.
     
  14. MadMat
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    MadMat New Member

    What is the definition of "rough"? Do you refer to a large swell, or a heavy chop? IMVHO, driving style and boat setup have an awful lot to do with it.
    Many people prefer a heavier boat for what they define as rough, but given a well set up boat with sufficient performance to "get on top", a startlingly good ride can be achieved - whereby the boat feels like it's travelling in a straight line and the sea is going up and down to meet it!! However, the same boat when too rough to get on top, can be quite uncomfortable slamming up and down the waves (but nevertheless safe), whereas a finer bow & heavier boat can "mush" through the waves much more comfortably.
     
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  15. Ike
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    Ike Senior Member

    Rough is relative to the size of the boat and the size of the sea. Rough on a lake can be 2 foot waves. Rough on the Pacific caost is anything that keeps you from going out. (LOL) 20 foot breaking seas on the Columbia River Bar is rough for anybody.
     
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