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Catamaran or Monohull

Discussion in 'General Yachting Discussion' started by dwlingren, Jan 14, 2019.

  1. GhostriderIII

    GhostriderIII Senior Member

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    Tipping doesn't happen all that much anymore. You're thinking of racing cats on foils.
  2. Pascal

    Pascal Senior Member

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    After seeing the galley up and aft on catamarans but also a number of power boats in the 50 to 60’ range, moving the galley on old 53 Hatt was the first thing I did when I started the refit. Sure we lost 6’ of salon space but we both love cooking and not being in hole down below is critical
  3. Oscarvan

    Oscarvan Senior Member

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    Mono hulls that are over canvassed/sailed too hard can get knocked down. If there's ANY time AND the designer hasn't sold his safety soul to the speed devil they will round up and righten themselves.

    The risk with an over canvassed cat is that speed and some heel combine to bury the leeward bow in the wave ahead. There's a lot of mass/momentum. If there's enough momentum it may cartwheel. The difference with the monohull is that there are fewer warning signals. No excessive heeling, no excessive rudder forces. A cat sailor has to sail more by the numbers.

    Any of the above will exert enormous forces on the rigging/hull and very often things go "boom" in the night.

    As someone said above, a prudent sailor, cat or mono, reefs early.
  4. Oscarvan

    Oscarvan Senior Member

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    I can see that 100% as I've spent a lot of time in the hole. One of the reasons I keep coming back to the galley up 58MY and the 58LRC
  5. AFranklin

    AFranklin New Member

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    Most cruising cats don't have enough wetted surface area to trip. If they get overpowered they just make significant leeway. Without daggerboards, flipping a cruising cat is a very difficult proposition.

    Galley down in a m/y works just fine if you are in good weather where you're grilling out topside most of the time:)
  6. Oscarvan

    Oscarvan Senior Member

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    Yes, works for the one who gets handed the platter with marinated meats and does the flipping. Not for the one who preps and presents the rest of the meal and has to clean it all up.
  7. brian eiland

    brian eiland Senior Member

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    Been away from this forum for quite a while, but when i was very involved with boating, multihulls were my choice. Here is a little posting I made about the importance of SHALLOW DRAFT

    I can't emphasis SHALLOW DRAFT enough. Here I am defining shallow draft as 4 feet or less. The Chesapeake Bay (America's largest inland water bay) has a few navigable deep water channels, but the vast majority of its area is 4.5 feet of water or less on average. If you truly want to explore the Chesapeake Bay and its many tributaries (one of the truly great cruising areas), you better have a shallow draft vessel. Ditto for the Outer Banks of NC (I once did them in a 37 foot sailing cat that I could kick up its CB's and rudders to draft only 24 inches). Its nice to have a shallow draft for the Florida keys, and the 10,000 island area of SW Florida, and those inside waterway passages of the west coast of Florida. Gunkholing is so much fun, and you miss some of this fun when your vessel draws too much water....you end up passing many delightful spots for fear of running aground.

    If you are intending to do the east coast, then around Florida, you might well consider doing the popular 'Great Loop', up the Mississippi, to the Great Lakes, down the Erie Canal, etc.

    And don't forget the Bahamas that whole chain of islands is structured on a shallow ocean shelf that is a delight to go cruising across rather than around, especially with those crystal clear waters. Shallow draft is king!
  8. Oscarvan

    Oscarvan Senior Member

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    In my experience skinny, but not THAT skinny. On the last boat our draft was 4'6" and I wasn't scraping bottom. There were a few areas where I had to pay attention but generally speaking there was plenty of water, even in the nooks and crannies. That said, 6 feet would hamper the fun a lot more as now you need 8-10'
  9. AnotherKen

    AnotherKen New Member

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    That is why I meant this as advice for an inexperienced sailor. They are much more likely to get into a situation where they at least get close to tipping the boat. And yes, while Catamarans do tend to be more stable, when they do reach the tipping point or pass it, they are much harder to recover at that point. Whereas with a monohull, while easier to get to the tipping point, they are easier to recover from that state also.
  10. Oscarvan

    Oscarvan Senior Member

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    Not talking about a sudden gale force gusts and the resulting "knockdown"..... But anything short of that the properly designed monohull will save you from yourself if you are over canvassed and or over trimmed. As the boat heels the changed hull shape and the changed relationship between the sails and the relative wind will move the center of lateral effort and the center of lateral resistance around to the point where the rudder can no longer overcome the luffing tendency no matter how hard you steer.... (in fact it will stall out) and the boat WILL round up.

    I remember having a heated discussion with Gerry Douglas, the Catalina designer, about the fact that one of his boats would round up at about 20º of heel.... to protect me agains myself. I thought that a little conservative as it made the "fun" sailing near impossible.
  11. HTMO9

    HTMO9 Senior Member

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    I can not talk about those french racing carbon monsters, as they are not my neck of the woods but bigger cruising catamarans will under normal circumstances (even in gail force winds) not tip over due to wind force and they do not round up (we call that a sun shot). Before a bigger cruising cat tips over, the standing rigging will break and mast and everything aloft will come down. But if a tip over really happens (due to rogue wave f.e.), the cat will completely capsize and the mast / sail becomes the sea anchor. As said before on this forum, the most stable position of a cat :). Thats why big cats all have to have emergency exits on the salon floor.

    A capsized larger cat can only be straighten up again in open sea over the bow. Means, with a safely floating capsized cat, the bow compartements are sealed off and then filled with water until the vessels bow sinks and eventually the boat turns around head over heels. This has been done by circumnavigators in the middle of the ocean and the journey could be continued (not talking about the internal damage). Smaller and offshore racing cats (should) have automatic inflatable emergency buoyancy devices mounted way up in the mast.

    But for me, the biggest difference, when I was sailing a larger cat for the first time (a Catana 58), was its behavior in the waves. This noticeable cork screw type movement, one has to get used to. And it is getting worse with bigger waves. Just imagine, taking a dune buggy with 20 ft track width at an angle of 45 degrees over the top of a big sand dune. Thats exactly what happens to a cat. Only the stomach of an experienced salt neck can take that type of movement for longer periods. Forget about your next turn point, go head into the seas and resume course later.

    The main difference with a cat rig is, single masted cats do not have aft stays and normally no salings (spreaders). Means, boom travel may be limited by the upper and lower aft angled stays. Means, if the boom goes wild, you are downgraded to a power cat, because your sailing gear is ruined. But a patenthals can happen on a modern rigged monohull with swepped spreaders too. Some other construction fundamentals are a vital for smooth and quiet sailing. First the open foredeck with a well designed tramaboline (the net) and the freeboard of the bridge deck between the hulls. In worst case, every small wave slamms under the bridge deck / foredeck and makes the ride very noisy and uncomfortable.

    Early british Prout Catamarans had a comletely closed solid foredeck. Besides their awfull exterior design, anything rougher than glacy sea was a nightmare. Tanks god, this company is bankrupt. The ugliest sail boats I have ever seen. That 34 ft Prout cat I sailed on in the Solent some 40 years ago, nearly stopped every time hitting a wave.

    Lagoon has a closed foredeck option on their new 78 ft power cat. I hope nobody will ever buy that option, unless this boat will only cruise on very calm inland waters.

    If I had the choice between a 40 ft monohull and a 40 ft cruising catamaran for long range blue water cruising, I would always take the cat. More living space, always upright sailing, just more comfortable with better performance and less fuel consumption. Cats are real mile eaters, close quarter tacking is not their world.

    And remember, galley up makes the admiral happy :p.

    patenthalse.jpg
    Do not forget, sailing is fun, believe it or not.
  12. Oscarvan

    Oscarvan Senior Member

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    That sounds interesting.... Although it yielded some entertaining video, a search for this procedure unfortunately did not yield any results.
  13. HTMO9

    HTMO9 Senior Member

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    I do not think a catamaran builder will publish videos about turning their capsized cats around. I remember pictures in the operating manual of a South African Catamaran explaining this procedure. But You need some ideal conditions to follow this procedure. On most videos of capsized boats you see, the crews are just happy to save their lives. And this regardless of being multi- or monohulls.

    First and most important point is to keep the capsized boat afloat. For this purpose, many blue water sailors have emergency buoyancy bodies in their hulls. Devices similar to inflatable matresses and stowed for example under the beds. In case of water ingress those devices are inflated with attached compress air bottles. They fill a good portion of the cabin and keep the boat afloat. This will buy you sufficient time to try any kind of emergency procedure.

    Here is a little video about a salesman talking about the advantages of multihulls over monohulls. Sorry Carl, he is from Denison Yacht Sales :D.



    He really points out most of my arguments from above. But one more point I extracted from these videos. You can not create or develope a fast power cat from a sailing cat by just removing the sailing gear and put bigger engines in. The typical canoe type hulls of a sailing catamaran do not make good planning hulls. This power cat in the video with its special planning hulls performes quite well, I must say. But with its closed foredeck it is only good for coastal cruising.