Project SeaCamel

Discussion in 'Sailboats' started by Kamelisko, Apr 16, 2017.

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    ALL AT SEA Junior Member

  2. CT249
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    CT249 Senior Member

    Cat ketches are often give a very large handicap allowance to make up for the fact that they are considered to be slower than sloops. If the allowance was wrong, and cat ketches were as fast as sloops, then cat ketches would win all the time. They don't, because they are slower than sloops.

    Two of the most famous cat ketches were Cascade and a boat called Denali. Cascade was a 37 footer that was much slower than the conventional 37 footers of her day. The only reason she won many races was because she was initially given the rating of a conventional 30 footer. Even racing against the Scampi 30s, the 37 foot cat ketch Cascade was sometimes beaten. When she was given the same rating as the conventional 37 footers, her owner stopped racing her.

    It was the same story with Denali. Originally she was Morning Cloud, a 44' Ron Holland design that was a world-class racing yacht. When she was converted to cat ketch rig, she was normally about as fast as a 36 footer. The main reason she won was that she had a very good handicap rating. As a cat ketch, she was normally significantly slower than she had been as a sloop.

    There are many tales about "unconventional" rigs that are faster than conventional ones. Most of them are tall tales. It's not hard to pick the rubbish out - just ask for specific details, like race results, boat ratings and rule details. Almost all of these tales are fantasies based on myths, and they vanish when you actually look at the details.

    It's probably the same with the claims that turning booms forward when sailing downwind makes you go faster. Lasers, Optimists, Finns and windsurfers can all do it too. If turning the booms forward was faster then some of the hundreds of thousands of Finn and Laser sailors and their Olympic coaches would have noticed by now. None of them ever turn their booms far forward when racing, because it is a slow way of sailing. We can see it just about every day we go sailing on these boats, and it has been proven to be slower time after time after time.
  3. Kamelisko
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    Kamelisko Trying to design and build my own boat

    You are probably right. They're slower in some degree. But in this case the main thing isn't top speed but ease of sailing and maintain. If thinking of ocean crossing speed I think hull is much more important than sails or rig type. In this case this project isn't about speed either but comfort and safety. And of course for performance the boat could be slightly over rigged for light winds and when having furling boom it can be reefed steplessly. (this of course compromises some of the adjustment of sail)

    Also if you think of the winches and stuff, with cat ketch you need basically two winches and ropes to control the whole thing. Tacking goes without touching anything - just turn the boat.

    I'll sail short handed through oceans much more confident with free standing rig than conventional where breaking single bolt can collapse the whole thing down.

    I think the problem of Cat Ketch (or schooner etc.) is that there hasn't been so much effort for designing them further. Sailboat designs are very much controlled by competition rules and there's not so much room for new (or this case old and different) designs. And the idea of turning boom forward isn't about the speed but comfort and safety again. With two sails forward on different sides the rig is self-rightening in downwind without risk of broaching.

    But thanks all the replies. I'll continue tweaking ideas into something... :)
    SailorAlan likes this.
  4. Kamelisko
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    Kamelisko Trying to design and build my own boat

    Just couple new image of the idea. This is currently little longer as I imagined. That's because I want to have tender garage included... :) Tell me what do you think!

    EDIT: made another one...

    Attached Files:

    Last edited: Jul 3, 2017
  5. Kamelisko
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    Kamelisko Trying to design and build my own boat

  6. Kamelisko
    Joined: Aug 2016
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    Kamelisko Trying to design and build my own boat

    Hello again. Just wanted to get back into this matter to ask if anyone has a real experience of dinghy garages? I haven't really seen them ever used in real situations (read: swelly anchorage). I just wonder if they're any good in real life situations when boat rocks from side to side in couple of meters of swell and you have to get the dingy out from the garage? Should I forget the idea of garage?

    BTW there's a few "new" videos available behind that link above.
  7. JosephT
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    JosephT Senior Member

    Interesting project...will follow. Regarding the dinghy garage, Ok for calmer waters. If you're in a hurry to deploy it in moderate to rough seas I would go with a dinghy cradle or hoist rig off the stern. I prefer the stern hoists that you can raise/lower with a block & tackle configuration. Makes getting to shore a lot easier. This will also free up aft space for cabin usage (berth, deck storage lockers, etc.).
  8. gonzo
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    gonzo Senior Member

    My first advice is to keep all dimensions in the same system. Having a length in feet and a beam in meters will only lead to confusion and failure.

  9. philSweet
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    philSweet Senior Member

    "I disagree. The only extra bulkhead required in the drawings would be one at the foremast, which could be a ring frame. The hull will be lighter than a stayed rig as the stay and shroud loads are eliminated."

    This is laughable. On a 40,000 pound, 50' cruiser ketch, the difference between a well-executed three spreader main + 2 spreader mizzen vs equivalent rotating freestanding wingmasts is about 10,000 pounds. The masts will be about 1500 pounds heavier, the ballast needed to offset the masts will be 5000 to 6000 pounds of lead or 8000 to 10,000 pounds of iron. And the boat structure will have to be a ton or so heavier. It's that bad. That's for similar materials. If you go for composite masts, it's just a matter of cost. Used to be about $100 per pound saved, but probably coming down now. Basically, a boat with freestanding masts needs the hull to be designed specifically for the unusually high center of gravity. It's a very different hull than a stayed-mast ketch or a cutter. This isn't necessarily a problem, but it is necessary.

    Unstayed masts would be worth a look if you are air-draft constrained but not water-draft constrained. If you are stuck with 50' sticks but are okay with a 9' draft keel, then things aren't quite so dire. But that isn't how the cookie normally crumbles. Also, forget full battens and a big elliptical roach. With freestanding masts, you want little to no roach and conventional short battens due to weight constraints. You need to minimize bending moment at the deck. This is true of all ketches and all freestanding masts.

    Ketches require very heavy mast fitments because you need each mast to be able to withstand full heeling moment requirements - there is no division of loads from the design standpoint. Running jib-and-jigger in 40 knots, the mizzen will have 100% of the RM 30 load. This makes ketches heavy. They aren't slow for their weight, they are just heavy for their size. Therefore, a ketch is where you most want a weight-efficient rig. And ketches don't work like a jib and main combo. You want maximum separation between the sails. You want access to the most spread of air. This gives a higher effective aspect ratio to the sailplan.

    We get these sort of wish-list posts about once a week. The choice of build method (easy isn't terribly helpful) constrains hull shape choices. Cost, length, displacement, keel draft, and air draft limits usually make the preferred rig type pretty obvious. An "easy" hull will consume at most 25% of the cost of the complete cruiser-fitted boat, so it's not really a big deal. Just buy a hull and do the other 75% yourself.

    Crewing effort, voyage duration, and technology level further restrict viable options. Most sailboats are motorboats most of the time, in spite of what the dreamers imagine. (I'm one of the crazies, I burned 7 gallons of diesel cruising the Bahamas for five months.)

    Motoring costs a lot less than sailing. The higher percentage of time you are prepared to run under power, the cheaper the boat and the lower the cost to own and operate at the design point. Years ago here, we compared motoring and sailing a cruiser of this size and concluded you needed to do about 100,000 miles of sailing before the sailboat version of the boat broke even with the motorboat version. So understand that sailing is the luxury mode of transport. Less of anything sail related means more boat for the dollar.

    Other odds and ends -

    "45 to 50 feet. (LWL) big enough to liveabroad in comfort but handleable single handed."
    30-33 feet = single hander. 33-38 feet = couple's cruiser. Over 40' usually wants a crew of four or more to cross any distance, as in more than one week at sea. But you can coastal cruise a 50'er solo if you aren't in a hurry. Plan on about a 35 -40 mile per day average. A bit more if you motor.

    "Dighy-garage behind"
    Uh uh. That stuff starts at about 3 million dollars. Real estate is really expensive on a boat, and the dinghy is about the lowest of the low in terms of creature comforts. But the dingy is an important part of a live-aboard. Usually there is a proper cruising dingy of about 9 feet, and if you plan on staying somewhere for a while, you buy a 13' jonboat and sell it when you leave. You are looking for one nobody wants to steal while it's tied to the dingy dock for a year while you work for cruising funds.

    "Large flat areas for installing solar panels"
    One for the boat, one for each person on board, and one for each little Adco compressor for fridge, freezer, icemaker etc. 200W each. Batts - one for the diesel, two for the house, 1/2 per person, one for the electric anchor winch, one for each little Adco compressor. I put a 150W inverter in each cabin - not distributed AC in this size. For liveabord (not cruiser), you probably want AC electric distributed to cabins and galley. Now you need big frigging inverters and charge controllers and battery chargers and monitor systems - $15K minimum to do it properly. Work the load side hard, 50'ers don't need distributed AC. They need a couple of AC circuits for when in the yard or in the marina, which is hopefully not more than 1% of the time. But do fit some sort of air conditioner that can function when hauled out on the hard. You'll thank me later.

    • Kat Ketch rigging
    • Two rotating free standing wingmasts
    • Full battened sail
    These are mutually exclusive. Pick any one you want and abandon the other two. Ketches have an aspect ratio problem. One way to address it is to maximize separation between masts and use low roach sails. Works nicely with in-boom furling though. Masts are heavy since both have to be built to the same strength as a single sloop mast. This is where the handyness comes from. If they aren't built heavy, you can't vary the sail plan in the normal manner. Ketches make terrific cruisers but are a waste of money in a live-aboard.

    "Engine and other ”dirty” things fully separate from interior to keep smells and heat away."
    They are dirty if they are isolated. If they are plonked in the middle of the salon, they tend to be looked after. You aren't going to get an Amel type machinery room in a 50'er. Probably not in a 60'er either unless you buy a million dollar Amel. Forgetaboutdit. If you can slide your hand down the side of the engine box without getting burned, you are doing good. I had to drill a hole in the engine box of my boat to get at the dipstick. It is 1 inch bigger than the spec sheet size of the motor. And somebody at the factory ran an electrical harness between the exhaust manifold and the block because there wasn't enough room to go around the engine. Oh, putting the icebox next to the engine so that they share an uninsulated partition is dumb - don't do that (Catalina 38).

    "360° Electric saildrive propulsion and alot of batteries"
    Option does not exist. Revisit issue in 20 years, but don't expect too much. We've been promised this for 150 years now and still no joy. In a bizarre twist of fate, the very first ever outboard motor did this, but it has not been seen since except for trolling motors, cruise ships, and station keeping platforms.

    "Fixed, clutter-free windvane installation"
    Option will never exist. Windvanes are the working definition of cluttery. I love 'em, but they will always look like something designed by a five-year-old Rube Goldberg. It's just their nature.

    Rendering suggestion - reverse the bevel on the transom - you need the cubes.
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