how do cats handle big waves?

Discussion in 'Multihulls' started by Guest1578132542, Jul 15, 2010.

  1. Alex.A
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    Alex.A Senior Member

    Just to lighten things up.... apparently not a hoax - both whale and boat ok - broken mast only!!! :eek: Dont think anything but a steel yacht could've.
     

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  2. CatBuilder

    CatBuilder Previous Member

    Terrible PhotoShop job!

    They didn't put in any turbulence on the "boatward" side of the whale and they really botched the whale's shadow on the hull.
    Plus do you think the guy at the helm might have glanced to his left?



     
  3. daiquiri
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    daiquiri Engineering and Design

    Off-topic:
    Hey Ray, Now that you said it I just recalled that we've had a conversation in another thread about your new cat's rudder. How about a little update (back in the other thread, of course) on how did you resolve the problem of sluggish turning? :)
    Cheers.
     
  4. Alex.A
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    Alex.A Senior Member

    Apparently not - made all local papers and overseas too.....
     

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  5. sabahcat
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    sabahcat Senior Member

    Looks more trimaran than cat to me
     
  6. ancient kayaker
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    ancient kayaker aka Terry Haines

    I don't really want to get into the mono vs multi debate any more than the bicycle vs car ditto, but does anyone know of a cat or tri lifeboat?
     
  7. mark775

    mark775 Guest

    It's actually a Stolcraft - The tri part ends just past where you can see it. It was supposed to be "the thing", the navy, naval architects; "best thing ever", etc.. admittedly not stereotypical cat but parked with "for sale" sign just the same.
    About the whale - I looked close, too. I beleive that the people are telling the truth but it sure looks like a fake picture - probably to demonstrate what happened. This happens quite a bit, actually. Two tour boats in SE were landed on a few years ago. I routinely have to pick up and move when these big, stupid things start getting goofy like this... Fun to watch - but from a distance.
     
  8. mark775

    mark775 Guest

    I will say that a lifeboat is a completely different thing, in effect just a bubble, heavier on the bottom. It doesn't have to be useful or comfortable - just survivable. And they appear to be able to survive a lot (maybe not the contents!)
     
  9. rayaldridge
    Joined: Jun 2006
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    rayaldridge Senior Member

    Mark, This is what Chris White says about engines in the Atlanta 46:

    "A twin screw cat is probably the most maneuverable vessel afloat; with one engine ahead and the other in reverse the wide separation of the propellers produce enormous leverage that will turn the boat without the need for forward motion, no matter what the conditions. Anyone who has tried to maneuver a large boat in close quarters on a windy day will understand that attraction.

    While nothing compares to twin engines, maneuverability under one inboard engine is acceptable and as an economy or weight saving measure this is a viable alternative.

    Twin Yanmar 2GM30F (27 HP.) engines will yield a range under power of 500 miles at a cruising speed of 9 knots with the standard fuel capacity of 90 gal. in the A46/LR. The range can be extended 50% by slowing down to 6 knots.

    A pair of Volvo 2003 engines will push the A-46 to 10.5 knots maximum, 9.2 knots at 2300 RPM. Addition of a turbo charger to the Volvo 2003 will bring the maximum speed up to 11.5 knots."

    But remember, these are sailboats, and they will go a lot faster and further under sail. Sail makes for a more comfortable boat, even for a cat. The great drawback to multihulls is that by their nature they cannot carry the weight that a monohull of similar size can. If overladen, they become slow and dangerous. So they are less suitable as pure powerboats, because they can't carry enough fuel for a long ocean passage. Guys whose route takes them through the Doldrums sometimes lash a drum of fuel to the cockpit, but it's likely that 500 miles of range will get you to the next patch of wind.

    Honesty compels me to admit that an Atlantic 42, a slightly smaller version of this boat, did capsize on Lake Michigan. Here's what the tugboat captain said after he went out and towed the boat back:

    "Why the catamaran capsized remains a mystery. The owner and his two companions had been sailing several hours in 15 to 18 knots of wind. They were inside the cabin with the boat on autopilot. In what can only be considered a 'microburst', it went over in less time than it took the owner to shut off the autopilot. He and the crew simply 'walked' up the wall and onto the ceiling where they remained dry for an hour and a half until the rescue divers from the Emmet County dive team arrived. The owner actually called the Coast Guard using his cell phone as his masthead antenna was 70’ under water."

    This was really dumb-- full sail, sheets cleated off, autopilot on, and everyone below. When a good cat goes over, it's usually either because they're racing, or they're idiots. In this case, the microburst might have resulted in hurricane force winds briefly-- we had one of those up in the NY's North Country a few years back. Took off roofs, knocked down a lot of timber.

    daiquiri, I haven't had time to work on the little cat lately. However, I'm starting to come to the conclusion that I was spoiled by Slider, and that whatever combination of factors made her such a snappy tacker may be difficult to achieve in a little boat without deep foils.
     
  10. CatBuilder

    CatBuilder Previous Member

    Glad I didn't bet on the whale! ha ha ha

    Mark: My bet is not for taking a catamaran into the surf. Surf will destroy any boat. My bet is for capsizing from sailing it...
     
  11. Westernman51
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    Westernman51 Junior Member

    That is a very good question. In the UK the RNLI (Royal National Lifeboat Instution), which does the search and rescue around the UK coast line (and does a very good job too and is entirely funded by donations), has boats designed and built to their requirements - as nothing of the shelf will do the job.

    As far as I am aware, they have never, ever built a multihulled lifeboat/search and rescue craft.

    Have they missed something, or do they know more than we do?
     
  12. Westernman51
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    Westernman51 Junior Member

    Ouch!

    I often leave the boat on the autopilot in those conditions with full sail up and everything cleated. I may well be below for a few of minutes if there is no traffic in the neighbourhood (e.g. to have a pee), with no one else on watch or on deck.

    My neighbour in my marina (a light weight cat), says his concern in rough weather is to avoid pitchpoling by going too fast (like the hobie cat in the youtube clip above).
     
  13. Fanie
    Joined: Oct 2007
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    Fanie Fanie

    Isn't this what you get into when the big waves start breaking :eek: I think the trick would be to have enough power to head through the waves and to prevent a broach. It should work ok to do a surf launch with a displacement cat and two motors if you're carefull about it.

    I have wondered about the same thing. A 9 -12m lightweight cat with two 80 - 120hp outboard motors on should make a great rescue vessel - fast, good in rough weather, good maneuverability, and a lot of deck space if it's say 6m wide.
     
  14. Fanie
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    Fanie Fanie

    The pitchpoling cat in the youtube vid could maybe fit an underwater wing that trims itself down at higher speed. The stern could have a speed adjusted pressure wing pulling it into the water and may prevent the stern from lifting up. The drawback would be that it will slow the vessel down a bit. Although it could work I doubt the idea would become popular - the main concern there is max speed, and not the pitchpole.
     

  15. Fanie
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    Fanie Fanie

    A clutched cleat may save the day. It's easier to trim the sails back than to right the boat.
     
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