Running planing hull at displacement speeds

Discussion in 'Powerboats' started by oldsalt1942, Aug 24, 2014.

  1. oldsalt1942
    Joined: May 2009
    Posts: 9
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Florida

    oldsalt1942 Junior Member

    I retired to Panama and am having a 23' panga hull built for me. I plan to add a cabin to it in the style of the narrowboats of the British canals (the panga only has a 6.5' beam). Pangas are planing hulls, but with tides around Boca Chica, where I will be operating, are 12 to 19 feet the flat bottom is good for grounding out between tides, or tucking up close into the mangroves.

    I do NOT intend on using the boat out in the open waters of the Pacific. I will be putting around in the various rivers and bays or the area and am not really interested in going anywhere fast. My question is, will I run into any real running problems putting a smaller outboard on the boat and operating at displacement speeds? After all, a lot of the boats have a small "kicker" that they use when trolling. What would be wrong with using something like that full time?
     
  2. Mr Efficiency
    Joined: Oct 2010
    Posts: 7,697
    Likes: 267, Points: 83, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    There would be a penalty in extra fuel use, but little else to bother you. You might use as much as twice the fuel, and that is probably pessimistic, but seeing it is only a small engine required, no great problem. If you were using it daily and for long periods, it might become a handicap.
     
  3. JSL
    Joined: Nov 2012
    Posts: 743
    Likes: 37, Points: 28, Legacy Rep: 41
    Location: Delta BC

    JSL Senior Member

    See if you can get a 'sail boat' kicker. They have bigger props for your weight.
    Watch the cabin weight & location-you don't want any stability or handling problems
     
  4. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 471, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    That style of hull will be pretty twitchy at displacement speeds, so mount a couple of hefty skegs well outboard so she'll still take to ground upright and hopefully control the low speed tracking issue you're bound to have. Low profile runners might do it, with less ventilation issues at high speed, though you'd probably need at least 4 across the bottom.
     
  5. sprit
    Joined: Jul 2013
    Posts: 46
    Likes: 1, Points: 8, Legacy Rep: 14
    Location: Lexington, MA, USA

    sprit Junior Member

    Most pangas are built heavy and strong for offshore use. If you want reasonable slower speed performance, consider reducing the scantlings of the boat. and using a canvas cabin. If you have a light engine, and keep gear to a minimum, your performance should be OK.
     
  6. rustybarge
    Joined: Oct 2013
    Posts: 533
    Likes: 3, Points: 18, Legacy Rep: 37
    Location: Ireland

    rustybarge Cheetah 25' Powercat.

    I can recommend the Tohatsu 6hp saildrive extra long shaft OB.

    Pushes my 1.25 tons cat at about 6kts against waves and wind no problem, and is easy to lift onto the transom at only 25kg.the long leg keeps the prop in the water when it gets choppy.

    [​IMG]
     
  7. tom28571
    Joined: Dec 2001
    Posts: 2,470
    Likes: 113, Points: 63, Legacy Rep: 1728
    Location: Oriental, NC

    tom28571 Senior Member

    It depends on what you are calling a panga. The name has come to be used for many different boats. Indigenous pangas that I saw in Latin America were basically double ended displacement hulls with horizontal wings added under the stern to provide lift for planing with larger motors. They had flat bottoms but rounded bilges/chines. Such a boat would be fine with smaller motors but the steering issues mentioned need addressing with some lateral resistance skegs, runners or some such. Your boat sounds like a normal flat bottom skiff.

    If your boat has a wide transom and will be heavy, it should have enough rocker to bring the aft bottom up near the surface for efficient displacement speed. Since you say its a planing hull, that will not likely be true and the problem will be when the speed in in the "hump" range.

    A bigger question is, why not build the boat for the intended speed range?
     

  8. tom28571
    Joined: Dec 2001
    Posts: 2,470
    Likes: 113, Points: 63, Legacy Rep: 1728
    Location: Oriental, NC

    tom28571 Senior Member

    To help clear up the matter, for some history of the real pangas look at :

    http://en.wikipedia.org/wiki/Panga_(boat)

    You will see there is scant resemblance to boats called "pangas" by several manufacturers who only capitalize on a catchy name. Most are simply skiffs made longer than usual. Makes for confusion much like the term "dory" and "sharpie" that are often used the same way.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.