Maximum simple trailerable power cruiser - looking for ideas

Discussion in 'Boat Design' started by Steve2ManyBoats, Sep 15, 2010.

  1. Steve2ManyBoats
    Joined: Sep 2010
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    Steve2ManyBoats Junior Member

    This is my first post to this forum, though I've lurked here for a while. I'm a 50 something that never grew up. I've got 11 boats, many of which I've designed and built, and am looking at retirement in 2 years. I'm a recent widower who was lucky enough to find a wonderful woman who loves the water as much as I do. My plan was to cruise as much of the US and Canadian coastline as I could, picking different destinations each year. However, since I have a waterfront home in Annapolis, I don't want/need to evacuate for a few years, just a few months each year.

    So there begins the plan. Most folks thinking of extensive cruising think of a big catamaran or a big trawler and dive right in for a multi year cruise. I have a different idea.

    Since I have so may boats, I also have a nice big turbo diesel pickup that gets 24 mpg on the highway to move them back and forth between houses and haul each year. My idea was to leverage that mileage and speed and buy/build a 40 ft by 8.5 ft (legal limit without permit) power cruiser, get one of those nice aluminum triple axle trailers the offshore powerboat guys use and drag my boat to a different destination each summer and winter and spend a month in each place just farting around getting to know each place. In general, here are the specifications of what I think I'll need:

    length - 40 - 48 ft.
    beam - 8.5 ft.
    power - 200 hp 4 stroke outboard
    displacement - 10,000 lb
    construction - ply with xynole and eopxy covering
    accmmodations- 2 adults
    cruise - 12 wiht a max of 18
    water -maybe 200 gal
    fuel - 100 gal
    no bridge but photovoltaics on the cabin top
    generally a lot of room and minimal gadgets

    I really like the general idea of the Chesapeake deadrise - long, narrow seriously veed bow and flat bottom aft and swoopy sheer )I've designed and built 2 20 somthing versions in ply, one of which I still own) though they're planked and way too heavy and can't live on a trailer. Maybe a plywood version.

    I've seen Karl Stambaugh's flat bottom Redwings (up to 40 ft) and like their look but I'm thinking they're too flat, too slow and too heavy.

    Likewise, Ruell Parker's Commuter 36 is interesting, but it's a little too light, small and fast for my needs.

    I've also seen some of Atkin's designs but none meet my needs.

    I'm concerned about seaworthiness of a very light boat with little draft - don't want it to be too snappy. I know the boat will be crossing the gulf stream on weather windows to the Bahamas so it's got to have a decent motion if things get a little snotty.

    I've built about 25 boats so I know my way around the shop.

    Anyone know of any designs I might be interested in or designers who might be working in this direction?

    Any advice greatly appreciated. Kindness to a noob to this firum also appreciated.

    1 person likes this.
  2. Easy Rider
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    Easy Rider Senior Member

    I am "manyboats" on the Atkins Yahoo site w 15 boats. Thought about changing to manyboats here but most know me as Easy Rider.
    I will be watching to see if this turns into an interesting thread.
    FAST FRED is working on a Seabright that will fit into a container.

    Easy Rider
  3. Steve2ManyBoats
    Joined: Sep 2010
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    Steve2ManyBoats Junior Member

    I hope this thread takes off, too.

    Easy - thanks for the post. I hope this thread takes off too. Rolling resistance is so much less than drag through the water, coastal and river cruising by trailer to a destination then sheltered cruising at each destination seems to make a lot of sense to me. There just seem to be so few designs around, much less boats built, for this purpose.

    I believe that the largest unpermitted trailer (and load - read boat) is 52 feet long by 8.5 feet wide. I figure that maxes out to a 48 ft by 8.5 ft boat. Bill Garden has designed some really skinny boats (like Tlingit which is 62 ft. by 7.5 ft) but none seem to be just what I need. Bolger also designed the Wyoming (a 51 ft by 8 ft "Bolger box") which is somewhat closer to what I need but I'm leery of the pounding of that flat bow - even though it's narrow - heading into anything other than a mild chop. I'd also be concerned that it might slap at anchor - and I'd be planning to anchor out more than tie up in a marina since most marinas charge by length, where long, skinny boats are at a distinct disadvantage.

    I was hoping to find something along the lines of an older Chesapeake baybuilt (when they made them longer and skinnier) designed for plywood with more cabin space - sitting headroom on the forepeak bunk, under the trunk cabin, an appropriate salon with standing headroom for helm, galley, head, and a hard canopy over 3/4's of the cockpit that I can enclose with eisenglas and canvas for a convertible second salon.

    In all ways, I'd consider this a "fair weather" coastal (not blue water) cruiser that puts a premium on efficiency, trailerability, simplicity, modest accommodations for two, modest speed and classic good looks.

    Anyone know of a design that's close or a designer who is working in this area?

  4. u4ea32
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    u4ea32 Senior Member

    Steve, I'm working on a very similar concept. Our design goal is to build a 2-4-6-8-10 boat: two can live aboard for indefinite periods, four for a weekend or so, six for a sit down dinner party, eight for cocktails, and a ten knot cruise.

    Easily trailerable, so we can cruise the lakes and rivers of North America, and so shipyard bills are eliminated. As I am sure you are very familiar, towing long loads is pretty darn easy, but over wide and over high is simply unworkable (entrances to MANY launch ramps leave scant inches on 8.5 foot beam trailers) , regardless of permits.

    So we are looking for any length up to about 20 meters (66 feet), but beam max is 8.5 feet, or better 2.5 meter (8'3"), and height on trailer max is 12 feet so the super structure does not trim trees as we drive down the road! And weight on trailer is probably 4 tonnes (8800 lbs) or less, to ensure economic towing and cruising.

    And the boat MUST be beautiful!

    Current concept is a displacement hull form, as 10 knots on a light, long hull does not require planing.
  5. gonzo
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    gonzo Senior Member

    Deadrise boats are long and skinny. They do well on a chop. The way they were set up for fishing, they have low freeboard and a large open deck. If you had a larger house and more freeboard, it would be more seaworthy. 200Hp may be more than you need for your target speed. If you are doing long offshore passages, twind 100Hp may be a good option.
  6. Wavewacker
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    Wavewacker Senior Member

    Hi, and welcome, I'm new here as well. I'm sure you have pulled boats down the road, but I would give more consideration to the towing aspect. It's not that your turbo D isn't big and bad enough to pull the Queen Mary II, but driving through gas stations along the interstate, trying to go through a drive through, trying to turn around at Wal Mart. Your truck is 18' the toung of any trailer will add 6 or 7, you're getting at 60', I've been on those public boat ramps and you have to go through parking areas to get to many of them, dodging boat trailers, many are crowded.

    How many second mates will you be taking with you that takes you over 40' ? IMO, 30/32 foot is a PITA to haul!
  7. u4ea32
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    u4ea32 Senior Member

    We are working two approaches right now, one is the "best way" and the other is the "single outboard" way.

    The "Best Way"

    Powerplant (propulsion and electric power generation) for this vessel is an interesting trade study, made more interesting by the following driving requirements:

    • Very inexpensive to purchase originally, install, repair, and replace.
    • Very quiet operation and power generation underway and at anchor.
    • Very maneuverable, as on-off trailer, docks, narrow waterways, congested marinas and anchorages, and getting through locks all are made trivial ONLY with really, really good maneuverability.
    • Very stable underway, as narrow light displacement boats will snap roll in most any seaway.
    • Very fuel efficient (really, very low operating costs), as fuel costs will increase while my income will decrease as I reduce my work and eventually retire.

    If we go the obvious approach, with engine, generator, bow thruster, stern thruster, main propulsion, and stabilizer fins, we've got a lot of complexity, which means cost to operate, and (to a MUCH lesser extent) cost of initial acquisition.

    If the boat is as light as the other constraints (trailerability, efficiency, limited beam) force it to be, then the power to push the boat will be less than the power for house systems which, due to the intent to cruise North America's interior during the summer, will include air conditioning. Therefore, there is the possibility for something like diesel-electric propulsion, as used by all modern cruise ships due to their much greater need for house power than their need for propulsive power for sub hull speed cruising.

    So the current best concept is to utilize electrical generation (probably a single 20KW diesel generator, augmented by solar panels on the roof for at anchor quiet ship operations), that drives four (!) azimuth pods. The four azimuth pods, two (port and starboard) at about 40% LWL aft of the bow, and two (port and starboard) at about 70% aft of the bow, together will be controlled entirely by computer, providing mobility forward, backward, laterally, rotationally, and most importantly, for anti-roll at any speed including zero speed. Also, they can provide dynamic positioning (DP) which is very useful for waiting in river current for a fuel dock, bridge opening, etc.

    One thing that is very, very easy to do is implement software control of multiple azimuth pod drives for these applications. No complex mechanical couplings that also transmit vibrations, nothing to break or fail, and no problem at all having multiple control algorithms for different situations. Well, its very easy if your day job is rocket science, as mine is!

    To make electric propulsion actually make sense, one needs high efficiency. Hard, but some firms are finally getting there (see Torqueedo). So if we were to build today (we will start build in two or three years), we would use four Torqueedo "outboard" units in wells that are conceptually similar to those for a Melges 32 rudder.
  8. u4ea32
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    u4ea32 Senior Member

    Just using a single outboard, combined with the skilled use of helm, thrust, and bumpers, is clearly a great way to go.

    The single serious drawback is the need to run at planing speed to resist rolling in a seaway. If one adheres to the "only protected waters" maxim, then this drawback disappears.

    I've got friends with large yachts that are great for ocean voyaging, so I can live with the limitation. I'd rather not, of course, but sometimes leveraging constraints can lead to really, really good solutions. And a single outboard, with solar panels on the roof, has an awful lot going for it.
  9. Squidly-Diddly
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    Squidly-Diddly Senior Member

    how about a cat? Click my handle for "all posts by..."

    or view my gallery.

    I've got sails showing on my cat but a big part of the concept is a "land based construction" type standard 4'x8' flat deck for building ANYTHING, or carrying RVs or trailer homes.

    Main disadvantage over mono-hull or 'scissors-cats' is it would be a little work to set-up and disassemble the deck.
  10. u4ea32
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    u4ea32 Senior Member

    I totally agree that one must consider getting though crowded public launch ramps! And I can't get negotiate many drive-throughs in my F-350 even when I'm NOT towing...

    Remember that the interstates are crowded with those very long semi's towing 53 foot trailers. Federal transportation regulations require that such rigs must be legal everywhere, with certain limitations such as the centers of ancient villages, towns, and cities.

    My current boat on the trailer is 40 feet from the ball to the outdrive. I have had some problems related to length: on a couple of local launch ramps I need to simply drive right over some islands and curbs due to the "artistic" way the landscape planners laid things out.

    But I don't often have length issues in other situations, including gas stations, shopping center parking lots, and the like. Once you are towing anything, you can't fit into a parking space ;) Since gas stations need to be configured to allow the fuel tanker trucks to get in and out, I can't remember a situation where I could not get in or out. Some easier than others of course!

    I've measured the tightest situation I have -- backing from the narrow street I live on into my driveway, putting the boat down the side of the house -- and I can easily do it until load exceeds 80 feet (!). With a little practice, and sometimes with someone behind the rig watching, its really pretty easy.

    The thing that makes very long loads like this (where the CG is close to the mid length of the boat) so easy is that the length from the ball to the aft axle on the trailer is what dictates turning circle. With a long boat, the trailer axles are still far forward of the transom.
  11. u4ea32
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    u4ea32 Senior Member

    Our original concept was a cat, but as we went through the design spiral it became clear that a monohull is really the way to go. We also explored a modern tri (really, 3 feet wide at the WL, with "training wheels"). These multihull concepts start out sounding really good, but they fell by the wayside because:

    Performance at these speeds (around 10 knots) are simply dominated by displacement: the lighter, the better. The total surface area of the boat (deck, topsides, underwater, bulkheads, ...) obviously is the dominant factor of the weight of the boat itself. A monohull clearly always has a substantial advantage in less surface area for any given size or volume, and hence has a substantial weight advantage, and therefore efficiency advantage.

    Also, close set multiple hulls exhibit terrible wave drag rise even at very low speeds: the waves combine in typical catamarans and trimaran configurations. Consider that the energy that goes into making those wakes comes from the boat propulsion system.

    While there exist multihull configurations where, by staggering hull arrangement, one can cause some of the wake waves to cancel, the constraint of the outer length-beam box makes such configurations substantially worse than a single longer hull... At least in the simulations I've been able to do, where the increased displacement due to the increased structure and surface area is taken into consideration. I could be wrong here, I'm not done with this investigation, but it does not look promising at all.
  12. Easy Rider
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    Easy Rider Senior Member

    Steve 2,
    Look at the Atkin
    The Marcia scaled up and maybe streched a bit to 8.5 x 36' would be close enough maybe. Would require much less than 200 hp. The flat part of the bottom would be under the WL at rest so would be quiet at anchor. With very little rocker (Marcia) an a long hull pounding should be minimal. Probably less than a shorter average V bottom like a Bartender. I would think when getting well over 4 - 1 B/L ratio bows being burried and OB props in the air would become a problem in certain length seas.

    Easy Rider
  13. Steve2ManyBoats
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    Steve2ManyBoats Junior Member

    More thoughts and reactions...

    David, Easy:

    Really appreciate your contributinos to this thread. David, interesting that our design briefs and intended use envelopes are so similar. As long as coastal really means coastal and not passagemaking, long narrow light power boats seem to become feasible. I agree that a catamaran is out. No way to make it work on an 8.5 ft. beam and a 53 ft. trailerable load. Maybe two trailers, but then it would be such a PITA to assemble it on site, it would never get used which would sort of defeat the whole purpose of a cruiser easily trailerable to a distant destination.


    Interesting idea about vectored propulsion. However, I'd cringe every time I ventured into shallow water with that set up. And I plan to venture into shallow water a lot. Over the last decade, most of my weekend cruising (locally in the Chesapeake) has tended to be in shallower areas where there tend to be fewer people. For me cruising is a private activity, not a social one. I'm the last person who would be found in a raft up. Given my predisposition for poking around shallow places away from the crowd, my inclination would be towards a single powerplant, most likely a four stroke outboard (though it might have an inboard well mount) with a long shallow stub keel to protect the outdrive from a hard strike. That long shallow keel will also likely be needed to keep the boat tracking straight in a crosswind since it's shallow draft and light weight will mean it will be blown about a lot and will tend to fall off the wind.

    On the topic of maneuvering, Bolger had noted that some of his Bolger boxes could be effectively maneuvered by using a simple bass boat trolling motor on the bow. They make these now for salt water, though the shaft would be too short for a tall bow. Maybe there's some way to increase shaft length so this would work. The fancy ones come with remote control for speed, depth and direction so if one could be made to fit, it could provide some pretty snappy maneuvering from the cockpit. Downside is it would look pretty ugly folded on the foredeck. Up sides are vectored bow thrust, no bow thruster, no holes below the waterline, and if it ever breaks, you unbolt it and fix it on your work bench or throw it away and get a new one.

    I keep coming back to a long thin Chesapeake deadrise, like one of the old hooper island draketails, though with a box stern. One they have at the Chesapeake Bay Maritime Museum, the Martha Jane, is about 44 ft by 7.5 ft. Rides like a dream even in snotty chop. Build that in ply with epoxy/xynole covering, hide an outblard in an aft well, lightweight house with a big cockpit hard cover that can be enclosed for a second salon and I think this might work.

    The hard part, for me, is not so much the hull as the interior design. I'll need to disguise the fact that the hull is only 8.5 ft. wide. Some of the RVs I've been in, although the surfaces are often tacky, have cleverly used long narrow spaces to make them feel more open.


    Have you worked up any design sketches yet?

    Thanks again for all who contributed to this post.

  14. srimes
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    srimes Senior Member

    what about putting the trolling motor in a well also? Then it could be hidden from view.

  15. thudpucker
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    thudpucker Senior Member

    I pulled a 19' Fifth Wheel trailer around the US for a few years. We had a Ford 7.3 diesel.

    The winds, changing lanes, reading signs from a long way off and getting to a fuel pump, Tunnels, overpass's, narrow streets with awnings. All things you had to keep in mind.
    You can pull your big boat around easy enough You learn as you go.

    As far as the boat goes, I went to Korea and back on troop ships. Both ways we ran into water I was certain the ship couldn't handle. At some point on the water, every boat is going to meet water too big for it to handle safely.

    Long skinny boats aren't tippy but they roll. Rolling, causes everything in the overheads to crash down on you.
    Plan your interior to put most things in lockers on the Decks. Sit on the lockers so your sitting high and nothing is gonna fall on you. Better visibility that way anyhow.
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