Looking for efficient low HP, need opinions!

Discussion in 'Boat Design' started by Wavewacker, Jun 21, 2016.

  1. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Making a Digger anything more than what she is, just isn't going to work well, particularly in deep water.

    Attached is the second smallest of my riverboat series. It has the elliptical transom shown, but a traditional transom version is also drawn up, which can have the outboard(s) hung externally, saving considerable cockpit space too. It also has all the usual options for her sheer treatment and cabin layouts typically offered with the riverboats. It's light, shoal, fairly narrow and reasonably efficient, particularly compaired to others of this class. She's a semi-displacement boat, but does best at displacement speeds. Well managed, she can go into deep water, though a steady diet of this (other than the occasional romp) might require some upgrades and modifications.
     

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  2. Wavewacker
    Joined: Aug 2010
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    Location: Springfield, Mo.

    Wavewacker Senior Member

    And I would agree, until Paul expressed concerns about Digger, it's a good looking boat and probably in the realm of my skill level. LOL :cool:
     
  3. Wavewacker
    Joined: Aug 2010
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    Wavewacker Senior Member

    Well, I set a time for myself to make up my mind, I think I have it.

    It was mentioned that for my first build I should build the dingy to my larger cruiser, I'm going down that road. Not necessarily a dingy but a much smaller boat, well, sort of, maybe.

    A garvey, simple box boat, 8' long, 4' wide, 2' sides, I may add a little flare to it and the bow will begin its rise about 6' back. This is what's in my head anyway. When that's done and it floats, I build another 8' section to bolt behind the bow section, then an aft section allowing a bit of rocker to the transom. All in, 24' but built over time, I can use section one and two fairly quickly I think. Doing one at 14 or 16 foot would probably be better practice for the bottom.

    Section 2 can have a low top, side curtains for sleeping at anchor or beached. Camp stove and the camp bucket can do for this year. Hopefully I'll get something wet. This is smaller river camping, the Buffalo and the White and messing around on local lakes, even the one about 100 yards from my house here in town. A bit like a large flatish canoe.

    But, that's not all, since Paul posted his river collection I've really been eyeing the pilothouse with the short cabin and I think he'll finally make a client out of me. LOL

    But, not so fast, I really like the longer cabin. I think this is probably beyond my skill level, it's a tad over my initial power request but for a boat needing a 20/25 hp,I think it would be worth the difference. My justification: How many Class B motor homes do you see at the Holiday Inn or the Hilton. Why, because they need a vacation from the vacation camper because it's too small, even in the Class A's you don't have a pool and a workout room!

    My thought is, go a bit bigger, more power, fuel costs a bit more, but it will cost less than having to go ashore more often for relief. So, okay, that makes economic sense.

    Just one thing, not sure I can bite off that bigger cabin in the initial chew, I'd like it to be built so that I may enlarge it to the long cabin version later on. I don't see why not.

    Just so happens I have some new, white, v-clad double hung insulated, tip out windows. Not sure of the size but there are some small ones that were to be used in a bathroom. Some more that would probably work in the pilothouse. (not my bullet proof windows BTW).

    And, another odd thing, years ago I began with a SOR of taking my motorcycle, well, that was pretty much shot down. But, at PAR's site, seems he rigged a boom on the Cooper Jr that can lift a Harley (he may mean a Harley Buell 250, LOL). Kidding PAR........But it looks like the same boom on that cabin cruiser too. Even beer kegs would be great! :)

    Sounds like a plan to me. At least build something smaller to learn the techniques.

    I'll get some practice before getting in over my head, at least cutting and gluing and operating my drill. Then I'll have something to pacify me for awhile because I'm sure that bigger cabin job is not going to be a 1000 hours for me, it might take me a long time. Any clue as to how long? Modest interior, no leather button and tuck on my boat.

    What do you guys think?
     
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    The mast and boom on Cooper and several other designs are all similar, designed to handle a hefty load. Cooper Jr's boom was a direct take off, of her bigger sister's setup. The Harley lifted was a FatBoy with hard bags, which screwed up the look and image of an FLST - you ain't so bad with a fairing, screen and bags, at least to me. The boom need to be reinforced, for this 700 pound load, but not a big problem.
     
  5. Wavewacker
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    Wavewacker Senior Member

    LOL, then this sets me back years, my initial thought was wanting to do the Great Loop and take my motorcycle for local touring.

    Some may recall my landing craft idea, then it was cat but that wasn't going to carry the load. Then to monos, then I was told it just wasn't going to be safe, I think someone said something about a lose cannon on deck.

    Gave up the idea, decided to buy a looper boat and not build that, but still wanted to build one. So now it's just a camp cruiser for the rivers and lakes, maybe a dash of saltwater someday.

    Now, the Great Loop is dimming as we really can't (or won't) be away from elderly parents for 3 or 4 months required for the loop. There are thousands of miles of rivers and lakes that can be seen in mini voyages, so here I am.

    All because a motorcycle wouldn't go on a boat under 30'.

    Now, I'm full circle, A full dressed Harley can go on a boat under 30 feet!

    Do I want to revisit that? I'm not sure I do, after accepting compromises I'm not sure I want to go through that spiral again.

    But I'm not out of crazy ideas yet, I'd like to figure out how to build a trailer that is really a boat, just take a plug out of the bow and pin the receiver in, then lower the wheels and take off! I think that would cause the inspectors at the license office to scratch their heads, is it a boat or is it a trailer.

    If you ever see a boat going down a river with registration numbers on the bow and a trailer license on the stern, you'll know I succeeded.

    :)
     
  6. socialb
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    Location: TX

    socialb New Member

    1 person likes this.
  7. Wavewacker
    Joined: Aug 2010
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    Wavewacker Senior Member

    Thank you Socialb, yes, that fits the bill alright! The recommended 30 hp is more than I wanted to go, I'd like to see that cabin go aft a little more too, but that's certainly on the right track. I can live with a 6' 8" beam.

    PAR, I PMed you back on your plans.

    Guess the first thing that needs to be done is to figure the weight of the souls on board, equipment and gear, I'm planning on a gen set with a batter bank for the trolling motor, 3/12v, not sure on that requirement yet but I don't want to run out of juice. I'm allowing 100 pounds for the gen set, that's heavy.

    At 1.5 fuel burn at 10 mph, looks like 30 gallons for a 200 mile range. I think that's about 200 pounds with plastic tanks and lines.

    Doesn't seem like this will be on the light weight side! ?
     
  8. socialb
    Joined: Jul 2016
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    Location: TX

    socialb New Member

    A couple thoughts: Lillistone estimates 10 kts, not 10 mph, and also estimates lower HP to drive it at that speed, so you wouldn't need to run the throttle all out.
    Michael Storer also has riverboat plans: http://www.duckworksbbs.com/plans/storer/venice/index.htm that provide a boat similar in length and width, has a much longer cabin, but is meant for slower speeds and calm waters.
     
  9. socialb
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    socialb New Member

  10. Wavewacker
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    Wavewacker Senior Member

    All good ones, Socialb, lots of choices, but back to the original SOR, easy quick build, self righting, not sure about that one for a motor cruiser.

    The waters of our lakes and rivers are not so calm, I won't be entering any kayak rodeo but we will certainly see chop, currents and some deep rapids.

    Flat bottoms have advantages but I'll say that Paul has convinced me to go with a pointy end in the front. :)
     
  11. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    What is your insistence on the self righting aspect? Given the general dimensions of your boat dream, self righting will be exceedingly difficult to achieve, particularly with the shoal nature and flat bottom requirements. You can get a boat of this general SOR with a very high initial stability point, but the AVS will likely permit a capsize, again given the draft, weight and build type limitations on it. What you could get, with some serious design work is a boat with high initial stability and the propensity, to not like remaining inverted very well. This isn't self righting, but is a tendency to have the boat recoverable, assuming it's sealed up tight enough and you've not breached in the roll over. Powerboats very rarely find the need for self righting, so why are you asking for this as a prerequisite?

    I'll email you in the next few days, I've been up to my ears . . .
     
  12. Wavewacker
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    Wavewacker Senior Member

    Thanks PAR, I received the drawings and from what I do understand of them they are unique for a smaller craft. I do love curves but I'm concerned (read as lack of confidence) about a curvey hull made in my garage.

    As to self righting, I have motored about 50 years on our lakes and never flipped my boat or got swamped and sank, might be luck but my ventures to unknown waters on large rivers are a bit different. I may be overly concerned.

    Insistence? No, just part of the boat dream. I suppose other precautions could be taken in the event of disaster, besides pdf's, like an inflatable kayak.

    A cabin top would aid in recovery, one that makes being inverted very unstable, if it goes to its side I can probably turn a narrow boat.

    So, yes, guess we can skip that self righting part.

    Thanks again for your counsel and time in the forums Paul.

    And, up to your ears, that's a very good thing in any profession. :)

    BTW, Paul, how many hours do you think your Chiusa will take for the hull and rigging for a small OB without the cabin being completed initially, to get on the water?

    Thought is, the whole boat could take me years, is it possible to build the cabin a bit at a time, adding on over time and still having stopping points to use the boat?
     
  13. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    It would be unlikely you could right a capsized boat (like the ones you want) without the help of another boat and some tackle. This size boat just isn't something you can crawl out on a centerboard and flip upright.

    Build times can vary wildly based on many considerations. How many boats have you built, what is a reasonable assessment of your skill sets, how organized are you, how well equipped is your shop, how much time can you put in per day, etc., etc., etc.

    There's not a lot to a Chiusa build, so a fair estimate might be 500 hours. If it's a first or second build, expect this figure to rise dramatically. Build time is also dependant on the ability to remain focused. If building in 2 - 3 hour bits and pieces, you can double (or more) the actual build time, simply because you're picking up where you left off all the time, which isn't very efficient. On the other hand, if you can apply 20 - 24 hours per weekend, with occasional 2 - 3 hours sessions during the week, you'll be able to get assemblies completed, without having to remember what you were working on, the last time you were at the project.
     

  14. Wavewacker
    Joined: Aug 2010
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    Wavewacker Senior Member

    Well, my shop is basic hand tools, table saw, skill, jig, reciprocal saws, compound miter, drills, sanders, levels, etc. I also have some air tools and nailers. I can build a house, but I'm not a finish carpenter, I've done some major rehab with labor hired, so I have more knowledge than skill. I think I can still cut a straight line (harder than most think too). Construction wasn't my profession.

    As to time, I'm retired so I can make time but there is always some distraction and there is beer thirty. Mentally I can stay on the job 24/7, obsessed but physically, I may be done for in 4 or 5 hours. I'd say I could easily do 25 or 30 good hours a week and still have a life.

    I'll need some help carrying around a 4x8 1/2 ply sheet, I can take care of lumber and smaller stock.

    It's my first build! I think ply on frame will be the easiest for me to do. Never worked with fiberglass really. I'd rather tape joints and epoxy not a full glass job.

    I'd like to keep the materials limited to the lumber yards, I inquired about marine ply and they answer was, "oh, that has to be a special order and it's very expensive". Not sure how much they didn't even want to quote it.

    I'm highly organized in the office, not so much in a shop keeping tools put up (LOL) but there isn't a problem with organizing tasks. I've done construction management from my desk and on site.

    As I mentioned, I may enlist help from a friend who is a master carpenter, but he's never built a boat either.

    I'll probably break down material purchases into phases as I have limited storage. I might put up a 30' x 24' tarp between two large trees for my shed over a concrete slab floor outside. I have steel roof trusses that would make a good strongback.

    So, let's say the skills of the average Harry Homeowner and a bit more in knowledge. I expect to buy a few more tools and lots of clamps.

    First time build!

    So, Paul as well as all others experienced, how long do you think I should plan on before I could splash the hull?

    Looks like at least 6 months, more like 8 with weather days, but I don't know.

    Then, can the cabin be added along with the fit out over time while using the boat?

    Thanks! :)
     
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