Best Inside Passage Trawler??

Discussion in 'Boat Design' started by DanRay, Sep 10, 2010.

  1. apex1

    apex1 Guest

    Well, not really 25 -30 in these conditions, but maybe 18 when the seagulls search for shelter. And that is a lot.

    A&R and Lürssen still have the plans, and I am sure A&R would be pleased to build you one (Lürssen does not build below 50m ), at say 20 meter LOA. Which would still be a decent size.
     
  2. BATAAN
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    BATAAN Senior Member

    Here's the original that the WW2 boats came from. All I need is lots and lots of money.
     

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  3. srimes
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    srimes Senior Member

    what was the beam on those s-boats?
     
  4. apex1

    apex1 Guest

    Though often spread, this was not the predecessor of the Schnellboot. Lürssen designed the first of their class independent from former civil craft (yachts). But of course, as it is in our industry, some influence will have been there.

    Regards
    Richard

    Data:
    Dimensions
    Displ. (Max): 110 t
    Length (Total): 34,94 m
    Length (Waterline):
    Beam: 5,28 m
    Draft: 1,8 m

    [​IMG]
     
  5. BATAAN
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    BATAAN Senior Member

    114 ft (35M) long and a little under 17 feet (5.2M) beam. Most had 3x supercharged MB or MAN diesels. Disp about 114 tons.
     
  6. BATAAN
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    BATAAN Senior Member

    Understand not the direct predecessor, just an early link in design chain.
     
  7. apex1

    apex1 Guest

    Yes, see my edited post above.

    With the 20 cyl. MB Diesel they were even capable of speeds above 40 kn!
     
  8. Commuter Boats
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    Commuter Boats Commuter Boats

    The original was 114.6' x 17.3' for a length to beam ratio of 6.62 to 1.
    So with the same ratio the 20 m boat would be 3.01 m in beam ( 65.6' x 9.9')
    The boater who is willing to accept the mooring cost of a 70 footer generally expects more creature comforts than fit into that footprint.
    William Garden did a nice job of utilizing the space in his "Captain Teach" ( 80'x11'), and Tad has drawn some very nice accommodations into his slender boats ( I wish he would show us an accommodations plan for his 80 footer). If anybody would care to pencil a quick idea of what might be done in a 20 m x 3 m I'd be interested in seeing your ideas.
    I've invested quite a lot of time in trying to optimize an efficient minimum cruiser for two. In the interest of gaining understanding as to how such a craft handles I built a 28' x 4' which I powered with a 25 hp four stroke outboard. At .75 gallons per hour ( approximately 8 hp) it ran at 12 kn and had decent manners, at full power and 2 1/2 gallons per hour it could do nearly 20 kn. I wish I was working on next evolution of that design which would be somewhere around 7.5' x 44' but life gets in the way and I first need to complete a 7'x31' for my lady ( she didn't like the skinny boat).
     

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  9. BATAAN
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    BATAAN Senior Member

    The problem in a displacement motor boat is always a trade off between narrow=fast and wide=comfortable. I have a very wide slow comfortable sailboat, but if I built a powerboat, I would give up the comfort for getting there very very fast. Dave Gerr's designs like NEEDLE show what can be developed. Now to make it more fuel efficient and faster.
     
  10. FAST FRED
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    FAST FRED Senior Member

    Now to make it more fuel efficient and faster.


    What you are really asking is how can I make it lighter.

    This is hard on a "Cruising" boat where refrigeration , air cond , heat , and other goodies are on the Desirement list.

    So the second question is what can you do without?

    FF
     
  11. BATAAN
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    BATAAN Senior Member

    Personally I lived on a 40' sailboat for 30 years w/o hot water, shower, a/c or refrigeration so I'd not have a problem with a stripped-out light fast boat. Most people would need more comforts than I do.
     
  12. apex1

    apex1 Guest

    Did I say:
    ?

    You even quoted it.
    And it was meant to point out that the original (downsized to 50 - 60ft) dimension was insufficient.
     
  13. liki
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    liki Senior Member

    It has already been done by a well respected professional.
    http://www.gerrmarine.com/power_70.html#ironheart

    But quite naturally it would be well possible to come up with a different plan, say a slightly larger pilot house to fit engine and bunkers under it.
     
  14. BATAAN
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    BATAAN Senior Member

    Here's Dave's study drawing for IRONHEART.
     

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  15. apex1

    apex1 Guest

    There is nothing new in our business..................
    But much was forgotten when fuel cost was no issue, especially in the US.
     
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