Pocket cruisers

Discussion in 'Powerboats' started by Guillermo, May 13, 2006.

  1. Guillermo
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    Guillermo Ingeniero Naval

    Having opened a thread at the Sailboats forum about small seaworthy cruisers, I've considered the oportunity of also studying this concept for the motoring side of it.

    So I propose now a discussion about 'pocket motor cruisers' understanding the term as motor boats under 30' able to do extended coastal crusing for a family (Up to 4 people), so not runabouts or dayboats, in a safe and efficient way.

    The idea is to gather here what has and is been done around this concept and discuss their pros and cons, as well as the concept itself.

    To begin with, I propose to have a look at WHIO, a very nice design from New Zealand, winning the Jens Hansen Cup for overall winner at the 2006 Seresin Estate NZ Antique and Classic. In this case WHIO was conceived for a couple cruising in style in warm climates, probably being rather a day boat with cruising capabilities, which would be in the 'lower' end of this thread's purposes. Design is from Peter Sewell and Bill Simpson.

    http://www.steamlaunch.co.nz/Whio.html

    MEASUREMENTS
    LOA 9.1 m
    LWL 8.9 m
    BOA 2.24 m
    Fuel 120 lt
    Displacement 1350 Kg

    DIESEL ENGINE
    Make Toyota
    Type 2C 1800cc
    Hp 52

    PROPELLER:
    S/steel 21.5 x 21.5 in

    AMENITIES:

    Built in fridge and freezer
    Berths for 2/3
    Economical LED lamps
    Depth sounder
    Portable gas stove.
    At present a Portaloo is provided, but is intended to install a drying type head.
    Awnings are provided to enclose the after part of the boat.

    PERFORMANCE:

    Fuel consumption : aproximately 2 litres per hour at 10 knots. Accurate measurements have not been made for higher speeds but is estimated that it should not be greater that 6 to 7 litres per hour at 17 knots.

    In easy sea conditions she cruises comfortably at 15 knots and 12 in heavier conditions, Whio rides smoothly with very little pounding. She steers very well running before the sea with no tendency to broach.



    The following parameters were considered imperative in the design of 'Whio':

    - The overall dimensions have to be below those which would incur the necessity of an oversize permit for trailering.
    - In the interest of fuel economy and trailering 'Whio' has to be light and wherever practible the lightest materials possible must be used used.
    - 'Whio' has to be capable of making coastal passages safely and at speed and be able to cope comfortably with adverse sea conditions.
    - ...'Whio' has to have the appearance and elegance of a classic Edwardian launch.
     

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  2. tom28571
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    tom28571 Senior Member

    Guillermo,

    Are you proposing a discussion of Peter's boat or boats for coastal cruising in general?
     
  3. Guillermo
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    Guillermo Ingeniero Naval

    Boats for coastal cruising in general.
     
  4. tom28571
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    tom28571 Senior Member

    On the home page of the forum, look down near the bottom at the Option One thread. Several people discussed just this kind of boat over a long period of time.

    WHIO is a beautiful boat with exceptional performance. It is, however, a boat occupying a narrow niche that will not appeal to a lot of people. The accomodations are more spartan than most will accept. Peter had a well defined goal and stuck to it throughout the design and construction of the boat. The construction is pretty advanced for a novice and will not be inexpensive for a commercially built boat of this displacement. Peter is planing to build some for sale though. Since New Zealand is a more boat consious nation than we in the USA, perhaps they can find appreciative buyers there. The boat deserves an audience and I wish them luck.
     
  5. Guillermo
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    Guillermo Ingeniero Naval

    Thanks, Tom.
    As far as I understand, in Option One the Specs were:

    Size 29 - 32 feet.

    1 Coastal hopping
    2 Trailerable
    3 Range 300 miles
    4 Crew, 2 minimum
    5 Price range, under 50K US, for home built.
    6 Must be able to carry on a normal conversation at 3/4 throttle.

    1. Max speed 25 - 28 knots
    2.Max Cruise 20 - 22
    3. able to maintain planing down to 12 knots and economical to operate throughout its speed range

    Some preliminary scketches were posted.

    But what I'm looking for is to show up what boats are in the market already (or in designer's boards), under 30', be them trailerable or not, not price limit.
    So, this is not a thread for designers only, but for everybody just wanting to share boats they know within the scope of the thread, and discuss about them.

    Cheers.
     
  6. Guillermo
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    Guillermo Ingeniero Naval

    Some very nice pocket motor cruisers from Paul Gartside. 22' (3) and 24' (2) designs.
    http://www.gartsideboats.com/catpow.php

    Specifications for 22 Ft Motor Cruiser "Jennifer"
    Length overall 22 ft 0 in
    Beam 8 ft 0 in
    Length waterline 21 ft 0 in
    Draft 2 ft 3 in
    Displacement 4700 lbs
    Fresh water 100 liters
    Engine Perkins M30 29 BHP @ 3600RPM
    Fuel consumption 2.47 liters/hour
    Fuel capacity 260 Liters

    From Paul's:
    "She is comfortable, quiet, warm, and secure. Two steering stations allow for al fresco cruising when the weather is fine and cozy comfort when it is raining, as it often is on the BC coast. She has room to stow enough stores to be self sufficient in isolated areas for quite a while. Her accommodations, while compact, have all the necessities - heating stove, galley stove with oven,sink, head, good comfortable berth, comfortable seats. Special attention was given her soundproofing, so that even though the three cylinder diesel is forward under the double berth, she is quiet enough that conversation can be carried on at normal level. Fuel consumption is 2½ liters per hour at 6 knots and cruising range is 800 nautical miles."
     

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  7. tom28571
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    tom28571 Senior Member

    To make any headway, you need to do like Peter Sewell and set some goals that define the boat. Gartsides boat is very nice but it is 6 knots. Your original post implies that you want to move much faster than that.

    In the powerboat world there are displacement boats, semi displacement or semi planing boats and full planing boats. They are completely different concepts and call for different design directions, and consequent compromises, from the outset. I know of no boat in the size range you want that meets your other desires. If you can accept displacement speed or even semi-displacement speed, there are many, many boats to consider. If you want planing speed from just above displacement to above 20 knots with easy trailering, crew comfort and economical operaton, the list of commercially available boats that meets your other requirements gets very small - like zero. My boat, which is described in the Option One thread is an example, like WHIO, that sticks to a rigid set of goals. I'm currently working on a 28' version with the (nearly) same goals.
     
  8. Willallison
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    Willallison Senior Member

    I too think you need to narrow your parameters somewhat guillermo. (Though it's worth noting that neither of the craft you've posted meet your initial requirements - neither will sleep 4 people, let alone accomodate them for an extended cruise...)
    For instance, I had a Searay 270 Sundancer for a few years ( http://www.boatdesign.net/gallery/showphoto.php/photo/114/cat/500/perpage/24/ppuser/124 ) A young family of four could cruise on her extensively for a week or more - I did on a number of occaisions. However, I'm not sure it meets what I think you're lookinig for. With a range of under 200nm and only 90 litres of water, you'd probably be a bit hard pressed to be completely autonomous for a week.

    You would also have to define what you mean by seaworthy too....

    In the displacement world you could look at the Willard 30
    http://www.trawlerworld.com/w30_bermuda.htm
    As Tom suggests, there are any number of boats that might fit within your parameters...

    ps. Tom - when do we get to see drawings / pics / progress re "Big Liz" (no disrespect to your wife intended...)
     
  9. Guillermo
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    Guillermo Ingeniero Naval

    Thanks a lot, Will and Tom.
    Willard 30 is a very nice displacement long range small cruiser, much in the line I think this kind of boats should be for load carrying abbility (so allowing for long periods without re-provisioning) and fuel efficient motoring. I love the type, and adding some sail assisting-roll damping rig (not as much as to be called motorsailers), makes them an excellent option, in my opinion. I would appreciate very much all possible info on this kind of displacement boats.

    But I do not want to learn only about those boats, that's why I didn't narrow the search. Fast cruising motor boats are also an interesting possibility for extended cruising, if you are in areas where provisions can be easily made, so you do not need to overload the boat. Something like a marinas-hopping-mixed-with-some-overnight-stays-at-anchor cruising scheme. I'm really interested in knowing more about this last type of boats. More interested than in the displacement ones, to be clear.

    As to the crew, I said "up to four", so this meaning 4 being a top limit, but no a minimum. Sorry if I didn't explain myself. To clarify, let's say from 2 to 4, but the higher the number, the better.

    May be seaworthy was not the right word. What I meant was sea going ability, so EU Design Category C, or higher.

    Cheers.
     
  10. Willallison
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    Willallison Senior Member

    on that basis, there are any number of boats to choose from - thousands in fact.
    I'm not sure what CE certification the Searays carry - probably C

    One of my favourites are the Nimbus range of boats www.nimbus.se

    But it really depends on what style of thing you want to look at. As I see boats fall into one of two camps.
    1. The less is more camp
    2. The cram more into less camp.

    My Searay was most definitely in the 2nd group.
    Toms lovely Liz in the first group
     
  11. Guillermo
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    Guillermo Ingeniero Naval

    Yes. A problem....
    To refine search for fast cruisers, maybe we should limit things to the following:
    - Pilothoused
    - Full load considering fuel, 4 people (top), their personal equipment and provisions.
    - Full load top speed something like 18-20 kn (+/-), so no 'sporty' boats. Boats have to be designed with fuel consumption efectiveness (reasonability?) in mind, as they have to be intended primarily as extended cruising boats, even if it is in short trips from harbour to harbour.
    - The best or more interesting, in poster's opinion :)

    By the way, I like quite a lot the Nimbus 28 Familia (And not only because it has an spanish name!)
    http://www.nimbus.se/modelPageCoupe.aspx?pageid=438
     

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  12. tom28571
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    tom28571 Senior Member

    The following is excerpted from some of my other stuff but I think it fits here.

    Displacement boats are restricted to speeds below the "hull speed" of the boat determined primarily by the waterline length. For most smaller boats this will be about 6 to 7 mph. Planing boats can run at very high speed but tend to behave very poorly between their hull speed and up to about 16 to 20 knots. In this range they will assume a bow high - stern down attitude, make large wakes, steer poorly, absorb gobs of fuel and be generally unpleasant to be aboard. Unfortunately, this mid speed range is just where most cruisers would like to run if they had a choice.

    This common characteristic is never relayed to a novice boat buyer by dealers or the sales brochures. These usually show the boat happily zipping across the water at high speed or sitting at the dock with the crew lounging about with a beverage in hand. Such poor behavior may appear for the first time when the proud owner takes the new boat out for a spin. Often there is great disappointment and the boat may spend far more time at the dock than the new owner intended. Perhaps one family member, usually the wife, does not like running at full bore all the time and the husband can't stand idling along at 6 mph. Of such circumstances are boat widows born.

    Semi planing boats will run in the intermediate speed range but do require higher power and fuel relative to displacement boats. They will generally be heavier than planing boats and still make large wakes when pushed into their upper speed range.

    ---------------------

    One thing to gather from the above is that your top speed range falls right where many (if not most) commercial boats that offer the amenities that you want are just getting onto plane. It's also the top end of the semi-displacement boat's capabilities. In both cases, the boat is not operating efficiently and is likely using gobs of expensive fuel. Neither is easily trailerable with anything like a family vehicle. Oops, I forgot about the monster SUV's now being found in driveways.

    It's impossible to say anything about boats without personal wishes and prejudices getting into it.

    Probably the quickest way to narrow the choices is to decide that the boat need not be trailerable. Next might be to lower your speed requirements so that displacement boats qualify. Then all your other wishes get a lot easier to satisfy.

    Will, as you know this is at the opposite end of the spectrum from my boats. The 28 is an attempt to satisfy the wish for more room and amenities and still hold on to the requirements for trailering, economic operation and speed above 20kts. While "Liz" has proven to be capable of handling some rough conditions, I refuse to call either of them sea boats.
     
  13. Guillermo
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    Guillermo Ingeniero Naval

    Tom,

    A 28' boat (24 Lwl) with 8.2' knuckle width at the stern, with proper forms, should go into full plane at something like 18 knots, as per the formula: Planning S= 4*LCG/(Bs^1/2), estimating LCG at 0.55 Lwl. And a similar estimative for a 30' comes to 20 kn. So my asking for 18-20 kn in full load condition pursued to screen for well conceived and built boats. But I admit it is a bit tight. What should we work with, 22-25kn? More? What's your opinion?

    I haven't stated that the boats needed to be trailerable. And displacement boats qualify, for sure. See my previous posts.

    Cheers.
     
  14. tom28571
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    tom28571 Senior Member

    I expect that your numbers are pretty close.

    The problem that I see is that there is no reasonable margin between minimum planing speed and top speed. This means that the boat is either full bore or idling at displacement speed since anything in between is not a useful speed to operate at. If you want to have a top speed in the high teens, I would suggest a semi-displacement hull which will operate at all speeds up to its maximum.

    My boats have full planing hulls and will operate smoothly and economically at any speed up to about 23mph but I don't think they will satisfy your other desires for cruising amenities. It's all compromises. When I hear of a boat or vehicle with no compromises, I shudder, since I know that there is one giant compromise - money.

    Look at Sam Devlin's boats for an idea of how boats that suit your wishes might look. http://www.devlinboat.com/
     

  15. Guillermo
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    Guillermo Ingeniero Naval

    Tom,
    Sam Devlin's Black Crown 29 with the 200Hp engine should reach 23 kn. She's a nice boat, although I do not like very much sterndrives. This boat having a pretty big interior, has a somewhat small cockpit, and even part of it is taken by the engine box, if I understand well her drawings (http://www.devlinboat.com/dcbc29.htm)
    Maybe a solution allowing to have a free cockpit could be the use of a JetPac engine (www.swordmarine.com) hanging out the stern. Have to think about this.

    By the way, Devlin has some nice looking Motorsailers designs I didn't know. Good for my Motorsailers & Motorsailing pages, thanks!
    Some of those MS can be arranged as extended cruising motorboats, in this thread's line.
     

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