20ft Nemesis Cat

Discussion in 'Boat Design' started by Alexander Peter Bromley, Feb 24, 2021.

  1. Alexander Peter Bromley
    Joined: Apr 2020
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    Location: South Africa

    Alexander Peter Bromley Student Naval Architect

    100% agree. A continuation of the hull kind of pod makes sense, instead of the perched effect some pods give standing the engines out away from the hull. I still see there are brand new boats coming out the factory with them that to me makes no sense. Build a longer hull then already!
     
  2. Alexander Peter Bromley
    Joined: Apr 2020
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    Location: South Africa

    Alexander Peter Bromley Student Naval Architect

    @Mr Efficiency an ode to shallow draft surf launching. You will see the third white boat's engines hitting the bank while he's running.

     
  3. Mr Efficiency
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    Mr Efficiency Senior Member

    Beats me why alloy isn't more popular, for those boats, the gel coat cops a beating.
     
  4. Alexander Peter Bromley
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    Alexander Peter Bromley Student Naval Architect

    Yeah its weird we have very few offshore recreational fishing aluminum boat builders over here, none that I can think of actually coupled with the fact they are generally quite expensive.

    Here is one with the boat sitting high and dry after an attempted launch haha.

     
  5. Mr Efficiency
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    Mr Efficiency Senior Member

    Monohulls I assume also launched similarly ? But being pushed down the beach like that, would fall on to one side.
     
  6. Alexander Peter Bromley
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    Alexander Peter Bromley Student Naval Architect

    To protect the gelcoat in the keel area most of the boats have a metal keel strip for protection.

    Yeah the mono's are launched the same way but are much more awkward.
     
  7. Mr Efficiency
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    Mr Efficiency Senior Member

    The more I see of these SA cats, I realize it is just an altogether different direction they evolved along, because of this beach launch caper being so common. They are not really comparable with American and Australian boats, which have a lot more in common with each other. But I notice in one video I saw, it was "shad" fishing season, I had a sneaking suspicion that would be what is known as "Tailor" here, and Bluefish in the USA, and it was. I don't notice much difference in the morphology of the fish, like I do with the "ski boats" !
     
  8. Alexander Peter Bromley
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    Alexander Peter Bromley Student Naval Architect

  9. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    Sometimes, you just have to go out backwards rather than forwards, like the crew of this Mersey class lifeboat did in Britain -



    Alexander, I haven't watched all the videos you posted above - how do they typically recover your cats in South Africa?
    Do you come in at full speed, and run up the beach as far as possible?
    Like this Shannon class lifeboat?

     
  10. Alexander Peter Bromley
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    Alexander Peter Bromley Student Naval Architect

    Wow I had to pick my jaw back up. He did well to recover to get off the bank, but why then back all the way out!? Once he had enough space to turn he should have swung the bow around.

    If you watch the videos I posted you'll see how they do it over here, we drop the boat off in the sand and then a tractor with a long pole pushes the boat off from the transom with the boat facing the oncoming surf.

    Coming in, run full speed up the beach running with a swash to get as high up as possible.
     
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  11. bajansailor
    Joined: Oct 2007
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    bajansailor Marine Surveyor

    Thanks, I had only watched half of the first video when I scribbled my post above - I shall find some time to watch all of them fully.

    I think that he was most probably worried about the risk of capsize if he tried to do that - in those waves, if one caught him broadside there might have been a good possibility of capsizing.
    Hence why he decided to just go backwards the whole way - he knew that the boat could take it, and they had enough power, even in reverse, to punch through the waves.
    The crew very sensibly all retreated to the foredeck, rather than risk opening the door to go into the wheelhouse.
     
  12. Alexander Peter Bromley
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    Alexander Peter Bromley Student Naval Architect

    Yeah wow some crazy footage! Those boats can take an absolute beating.
     
  13. cracked_ribs
    Joined: Nov 2018
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    cracked_ribs Senior Member

    I can tell you that personally, the reason I might keep backing out in those conditions is that the boat can definitely take the beating...but you've got all your guys on the exterior sheltering on the bow there. No way am I going to swing her fast around with the possibility of a capsize, or even major list, with guys on deck. I'd also want to avoid forcing them to do a quick reposition to the stern for shelter; if the boat is backing fine, just run it out of the surf zone and reposition the crew once it's safer to do so.

    I don't run a lifeboat or anything but I have piloted a crew boat around in heavy weather plenty and if the boat is sealed up fine and not taking on water, I'll do pretty much anything to keep the crew from having to do sudden maneuvers on deck in heavy weather.
     
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  14. Alexander Peter Bromley
    Joined: Apr 2020
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    Alexander Peter Bromley Student Naval Architect

    Fair point.
     

  15. DogCavalry
    Joined: Sep 2019
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    Location: Vancouver bc

    DogCavalry Senior Member

    Well APB, I hope your question about whether or not your thread will be popular has been properly answered. Some great stuff here!
    Come visit my thread, if you're up for some sea sled Madness.
     
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