Any hope for this one?

Discussion in 'Boat Design' started by afteryou, Jan 29, 2013.

  1. afteryou
    Joined: May 2012
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    Location: Southeast Alaska

    afteryou Junior Member

    I did not draw a napkin sketch for you because I have no preconceived idea how it needs to look. Plus I think the dimensions speak for themselves it’ll be a box that’s slightly pointy on one end. I’m thinking maybe whaleback the bow for a little more room in the bunks. Small closed wheelhouse leaving hopefully 12’ of open back deck. The engine would be housed inside a box in the wheelhouse that would most likely double as a table.

    List of what I want
    Around 24’ in length and not less than 10’ of beam, maybe as much as 12’
    Single diesel powered
    Shaft driven prop.
    Dry stack exhaust would be a must.
    Running speed light 18knts +
    Running speed loaded 12knts+
    Pack at least 3,000lbs. Salmon + ice/water 4,000 would be better
    Burn less than a gallon an hour at fishing speeds 1-3knts. Best guess maybe 20-40 hp needed to tow the gear and push the boat, weather depending.

    Why is it so short? Because short is cheap. Moorage, haul outs, bottom paint, wire runs, hydraulic hoses. I could go on like this for a long time.

    Why is it so wide? First reason I need the deck space if it’s gonna be short it’s gotta be wide.
    Second reason stability the boat must be able to break the gear I’m towing. Maybe five hundred pounds to break it off the pole then twelve hundred to snap the wire at the side of the boat. VERY dangerous if you get hung up on the bottom in an ocean swell and the boat cannot break free.
    The third reason and I’m guessing here is that I would need the flat surface area to plane with all the weight I want to stuff in this thing. I know I am on a line here possibly well past it and into the realm of not going to happen.

    Ok so how much horsepower would I need to make this work and how much would that engine weigh? Speaking of weight let me stack some more on there say 150 gallons of fuel and no less than twenty gallons of water, plus at least a weeks worth of food for two people. Oh and I almost forgot anchor winch and gear sufficient to hold the boat in at least thirty fathoms of water during bad weather. I guess while I’m at it I’ll add the diesel cook stove and the kitchen (galley) sink. :rolleyes: Ha ha ha! I guess the trolling guirdies (little winches that haul the lines up) and the lead weights would add weight worth noting. Somewhere in the neighborhood of 500 lbs all together. The weight would be located approximately four feet forward off the stern split between the two sides.

    Inside chop 3 to 4 feet the boat will pound like crazy that’s fine nothin’ can be done about it and I can live with that. It’s in the ocean that the boat will need to shine that’s where it matters. It will have to be safe in a North Pacific gale. Not that I spend a lot of time in weather like that but it does happen and I don’t want to have to worry about the boat. Keep in mind that part of the reason I want the boat to be fast is so I can run away when the weather starts to pick up. Most of the time however I’ll be going somewhere between a knot to three knots with stabilizers deployed.

    So is there any hope for this idea? What would need to change? Or should the whole idea just be bagged?

    Thanks for taking a look.
    1 person likes this.
  2. WestVanHan
    Joined: Aug 2009
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    Location: Vancouver

    WestVanHan Not a Senior Member

    Modern electronic diesels at the torque curve and on boost give over 20 hp/gal an hour.
    So at 40 hp you'll be burning ~2 gph,and as you'll want to be able to go faster you will be off the best fuel burn rate,so add more-2.5 gph?

    As for the rest-is this what everyone else is using?
  3. afteryou
    Joined: May 2012
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    Location: Southeast Alaska

    afteryou Junior Member

  4. Gilbert
    Joined: Aug 2004
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    Location: Cathlamet, WA

    Gilbert Senior Member

    If you really want it 12 feet wide I would suggest you make it around 8 feet longer.
  5. michael pierzga
    Joined: Dec 2008
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    Location: spain

    michael pierzga Senior Member

    And 20 to 40 hp ?

    Did you mean 200 to 400hp for 18knts ?

    or 20 to 40hp to go 1.8 knots ?
  6. afteryou
    Joined: May 2012
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    Location: Southeast Alaska

    afteryou Junior Member

    Gilbert, by traditional standards I would agree with you but if you look at length restricted fisheries new boats are commonly breaking the one third ratio. Bristol Bay gillnetters for example. They are capped at 32' and are pushing out over 15' beam in some cases.
  7. afteryou
    Joined: May 2012
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    Location: Southeast Alaska

    afteryou Junior Member

    20 to 40 hp to tow the fishing gear at 1-3 knots.
  8. midnitmike
    Joined: Apr 2012
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    Location: Haines and Juneau

    midnitmike Senior Member

    Now 32x16 is the new norm...if they get any wider they'll be


    PS. Sent you a PM
    Last edited: Jan 29, 2013
  9. Tad
    Joined: Mar 2002
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    Location: Flattop Islands

    Tad Boat Designer

    You don't mention construction material but I'm visualizing a giant aluminum pram...? For the hull to work at all though your required vast speed range it will be very inefficient at the bottom and top of operating speeds. For it to possibly work in the higher speed ranges (> 6 knots) will require the big fixed weights (this includes the engine) to be as far aft as possible, not up in the bow cabin.....

    Studies coming out of the UK are showing some indication that short fat high-sided boats may be more vulnerable to capsize......another un-intended consequence of length based licensing......
  10. sean9c
    Joined: Jan 2011
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    Location: Anacortes,WA

    sean9c Senior Member

    and 700+HP

  11. yipster
    Joined: Oct 2002
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    Location: netherlands

    yipster designer

    Speed consumption wide and what else
    Even a catamaran will be having trouble meeting all wishes but might be interesting to check how close it may get
  12. lobsterman
    Joined: Mar 2004
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    Location: Maine

    lobsterman Junior Member

    Check out Munson boats, i think that they are up near you, and might have a stock hull design that would fit the bill. Also there is another company up there that builds a landing craft type hull, that could work, but i can't think of their name at the moment.
  13. afteryou
    Joined: May 2012
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    Location: Southeast Alaska

    afteryou Junior Member

    So I was having my lunch scribbling down a few numbers trying to figure out how much everything on the boat would weigh and it doesn’t look good. Rough guess, I’m getting real close to 10,000lbs including engine, fuel tanks, fuel, fish, rigging, stove ect. This does not include the weight of the boat itself. 6 plus tons at 24’ long… yeah. Might work for a tugboat I guess :(

    So I might have to go a bit longer, but how much?

    Fuel economy is a real concern. I have compared fuel consumption with a few different fast sport boats over the years and it seems like their getting 1 to 2 1/2 mpg. With my current set up I get around 3 1/2 but I only go seven knots on good day. Most day’s time is money and if I want to make a move for a different spot twenty miles away it’s going to take me three hours to do it. If my boat went 18 knots obviously it would only take me a little more than one hour. How many fish would I catch in the saved hour and a half +? Who knows that’s why they call it fishing and not catching right. Hopefully it would be enough to pay for the extra fuel though.

    I was looking at some of the smaller bow-picker gillnet boats for sale on various broker sites in the 26-28’ range they claim speeds of 20+ knots with 220 hp Volvos linked to a stern drive. They could only pack around 2,000lbs but it seemed like most of them had a more modest beam.

    Having the engine mounted aft in the boat poses real problems for a troller. We need to play each individual fish up to the back of the boat and then whack the #$%@ out of it with a stick :D We need a clear open stern with our feet between a foot above and a foot below the waterline. Ideally we need to be able to freely move from one side of the boat to the other to play the larger more stubborn fish. The exhaust being in the stern of the boat sucks. Loud and stinky blowing in your face all day. Wet exhaust is even worse billowing around the back of the boat and getting the gear all covered in unburned fuel.

    Outboards and outdrives are an issue as well there are people who use them but they have problems with the fish getting the leaders caught in the prop or the fish themselves. Plus they just are not very reliable.
  14. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    something like a mullet boat?


  15. midnitmike
    Joined: Apr 2012
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    Location: Haines and Juneau

    midnitmike Senior Member

    That uniflite is looking better all the time...;)

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