Design challenge

Discussion in 'Boat Design' started by fpjeepy05, Jul 11, 2019.

  1. fpjeepy05
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    fpjeepy05 Senior Member

    All the 15' montauks that I have seen have a bilge pump in the cockpit and no overboard drains, but maybe that is only the older models.
    [​IMG]
     
  2. fpjeepy05
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    fpjeepy05 Senior Member

    You put a lot of time into this response and I really appreciate that.

    Basically, it is a boat that I would want, and my idea was that maybe it would be unique enough that other boater would want it as well.

    I would like to fish off North Carlina. 20-30 miles out. All seasons, for pelagics and ground species. And I would like to do it with 1-2 friends and for $20 in fuel instead of $200+

    Most people will say that is impossible. A book I read posted a question to entrepreneurs, "What currently not possible, would revolutionize your industry if made possible?" So when I say minimal cost I mean rock-bottom. And burning extra fuel is not an option if it is going to be a revolutionary product.

    I was hoping to stick with outboard for simplicity and cost. Diesels are available now, but sooooo expensive. Sea condition... you would have to pick your days, but if a storm rolls in quick you should be able to survive. I was envisioning self-rescuing. We made some of our boats self-rescuing by putting two to four 2" Pvc pipes through the transom at the cockpit height and plugging the interior opening with racket balls. When a wave crashed on the deck you had to pull the balls out quickly, which was frightening, and they usually stayed out the rest of the day after that. Our bigger boat has a much higher cockpit and it just has big 3x8" scuppers.


    I wanted 270 degree enclosure for protection from spray and wind during the colder months. Bow to stern access is for fighting big fish. Sportfish boats fight fish off the transom because they can maneuver the boat well with twin engines and don't have the option of fighting off the bow. I've found it easier to fight big fish on the bow of a small boat for a number of reasons.

    I was thinking a t-top with a vinyl enclosure that snapped or zipped to the gunnels. This way when hooked on a big fish one guy could unzip the enclosure and the other could walk the rod to the bow.

    Another option might be an asymmetrical half house. So a port side, a port windshield and a rooftop, but clear vinyl on the starboard.

    Area would be enough space for 2-3 guys to hide under. Height would ideally be standing room, but if the beam is narrow and the CG too high it might have to be a seated area.

    I thought this panga would be super fuel efficient, and cheap to build and I know they are built to handle rough water. Adding all the other requirements on my wishlist would be the difficult part.


    Why do you say that? Taking a 50hp down to a 10hp seems like a large drop.

    What's the benefit of the blunted bow? Seems to me like it takes away the ability to cut through waves.

    If I understand the purpose of this correctly it is to move CG forward. Which makes sense, but makes fish-ability worse. I think finding a compromise here would be best. So rather than mounting the motor 4ft forward of the transom, maybe only 2ft, or something of the sort. Ideally, a guy should be able to walk a 6ft rod (loaded with a fish) around the transom without hitting the prop.

    Is wind drag really that high at 16 knots?

    That is a beautiful boat, and I'm all for that. And I guess it makes sense because horsepower was much more limited in those days. I feel like changing from a heavy IB to a OB might cause some performance issues, but I'd have to look more closely.
     

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  3. HJS
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    HJS Member

    This is a boat I designed for fishermen in the Gambia, 7,0 x 1,5
    Just now I design a larger boat with similar characteristics.

    JS
     

    Attached Files:

    philSweet likes this.
  4. fpjeepy05
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    fpjeepy05 Senior Member

    Is the 1.5 beam the chime beam or BOA? Seems like it could get a little squirrelly on plane if the planning surface is only 1m, but you would know better than me.
     
  5. HJS
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    HJS Member

    The planing surface beam is one meter. No poblem. Yes, I know better than you. ;-)
    JS
     
  6. fpjeepy05
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    fpjeepy05 Senior Member

    Doesn’t chine walk?
     
  7. jehardiman
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    jehardiman Senior Member

    Actually self-bailing cuts both ways. Water out = water in. Whalers typically have just a little water in the cockpit sump when stopped, and drain underway. That photo is not a factory ABYC sump pump install as 15/150 Montauk's were never factory fitted with one. It is occupying the space of the drain sump and would be impossible to get the drain plug out for operation. Seeing that the discharge has no hose means it is useless, and my guess is that it is not for operation, but something else, like to pump rainwater out (see this thread Classic Whaler: Boston Whaler: Reference: Bilge Pump http://continuouswave.com/whaler/reference/bilgePump.html).
    fpjeepy, I'm not trying to sell anything, but rather direct you to the best solution to your request. FWIW, I have had many sponsors over the years enter with a detailed shopping list like your first post. Generally that means that they have already decided for themselves what they want (rather than what they need) and have written down what they think supports their decision. Most, like you, are shocked to find out their pre-conceived notions are not totally correct. As gonzo and Phil have stated, a freight canoe and a panga do not fit your original requirements.
    What you want does exist, but maybe not in a way you think. FWIW, sea sleds (whaler type hulls) and v-bottomed garveys were developed for offshore fishing in the mid-Atlantic states. The reason is specifically because they were more stable and had better load carrying than round bottom hulls such as a canoe. It is precisely this improved stability that gives them a harsher ride in some conditions, but as it is wave slope, not wave size that is dangerous to a small boat, makes them safer overall and less likely to swamp.
    Oh, and why a garvey has a front transom? Ease of construction, less cost, and saves weight both forward and high, both of which improves stability which makes it a safer boat.

    edit: left off the last word.
     
  8. HJS
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    HJS Member

    16 knots. Around hump speed ?! Never heard about it.
    JS
     
  9. fpjeepy05
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    fpjeepy05 Senior Member

    That was the best image I could find on a google search and it looks like every whaler I've ever seen. I have never seen a whaler with scuppers. If I don't have scuppers and you are still claiming it is self-bailing, please explain. Pulling the drain plug while on-plane is not self-bailing.

    Freighter canoes are not self-bailing. They do not fit my recommendation. I don't want a freighter canoe.

    Phil said a panga would not work but provided no explanation.

    Stop saying sea sleds and garveys have a better load carrying capacity. This is just not true.

    Nor West 26 Chisasibi.JPG
    150 montauk.JPG

    Maybe I am not the one that has already made a decision, but maybe you trying to force the Boston Whaler as the solution to everyone's boating needs.
     
  10. fpjeepy05
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    fpjeepy05 Senior Member

    It's not a traditional "chine walk" but if the boat was on plane and rolled to port... the big flat could touch the water. It would create drag on the port side of the hull which would produce a yaw moment which causes a roll moment in the opposite direction which wets the flat on the starboard side of the hull. Repeat.

    I have a 5m x 1m soft bottom inflatable (google Saturn Kaboat) It rides on a 50cm air floor and has 25cm tubes outboard of it. and when lightly loaded it has this behavior if the boat leans and the tubes touch the water. It's moving slow enough it's not unsafe, but it is a weird feeling.
     
  11. HJS
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    HJS Member

    With such a primitive form one cannot expect anything else. Just because it floats and looks like a boat, so it's not a boat.
    JS
     
  12. fpjeepy05
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    fpjeepy05 Senior Member

    Do you have any photos or videos of your 7x1.5m running?
     
  13. fpjeepy05
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    fpjeepy05 Senior Member

    Question... Maybe this is worth starting a new thread, but I'll try here first...

    Longitudinal center of gravity is important for semi-displacement and difficult with transom-mounted outboards. Has anyone ever considered putting a counterweight on a long bowsprit? The net weight would be reduced because of the longer lever arm, and maybe it could hinge up for docking, etc.
     
    Last edited: Jul 30, 2019
  14. DCockey
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    DCockey Senior Member

    The longitudinal moment of inertia would be increased, and the pitch frequency would be reduced. Trim tabs or interceptors are a simpler way to control longitudinal trim.
     

  15. fpjeepy05
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    fpjeepy05 Senior Member

    Simpler... Yes. More efficient at semi-displacement speeds... No.
     
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