Pete Culler 1840 british cutter for Bruce Northrup, plans

Discussion in 'Wooden Boat Building and Restoration' started by dave2700, Aug 27, 2020.

  1. dave2700
    Joined: Aug 2020
    Posts: 13
    Likes: 0, Points: 1
    Location: uk

    dave2700 Junior Member

    HI. I'm wondering if anyone knows anything about where I could get the plans for the Pete Culler designed 1840 british cutter for Bruce Northrup. The plans should include the table of ofsets anything is helpful. Thanks

    stay safe
     
  2. DCockey
    Joined: Oct 2009
    Posts: 4,818
    Likes: 370, Points: 83, Legacy Rep: 1485
    Location: Midcoast Maine

    DCockey Senior Member

  3. gonzo
    Joined: Aug 2002
    Posts: 14,735
    Likes: 756, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    Those plans are enough to generate a table of offsets. It is not too hard to do. They even have the diagonals, which are great to double check the accuracy of the lines. Are you thinking on building one?
     
  4. SamSam
    Joined: Feb 2005
    Posts: 3,900
    Likes: 197, Points: 63, Legacy Rep: 971
    Location: Coastal Georgia

    SamSam Senior Member

    How would you do that, just use a scale on the paper drawings? and then work it out lofting? Could it be done to where you could feed accurate numbers into a cnc machine?
     
  5. DCockey
    Joined: Oct 2009
    Posts: 4,818
    Likes: 370, Points: 83, Legacy Rep: 1485
    Location: Midcoast Maine

    DCockey Senior Member

    That is the way it was done when Culler drew the plans. If Culler had created a table of offsets he would have done so by measuring the paper drawings with a scale.
    For the CNC machine to do what - cut frames, carve a model, ???

    CNC machines require more than "numbers". They need a digital model of what is to be cut, frequently a CAD model, in a compatible format, for example .dxf format. A CNC machine can't do anything with just a table of offsets.

    One method to input the required information from lines drawing into a CAD system is to scan the lines, display the scanned lines in CAD and trace over the displayed lines. Another method is to enter a table of offsets to create a set of 3D points. Once the lines drawing information is in the CAD system it can be used to create a suitable CAD model to use as input to the CNC system.

    One approach is to create a CAD model which is directly analogous to traditional lofting of a set of curves. The curves can be reconciled (made to intersect as appropriate) and faired as in traditional lofting. Curves can be created from the set of curves to use in cutting frames, backbone parts, etc analogous to creating physical templates from a loft. However the lofted lines by themselves, even as a CAD file will not be sufficient for using the CNC machine to cut a surface.

    Another approach is to use the information from the lines in the CAD system to create a surface which I refer to as a virtual half-model. That surface can be used as input to the CNC system for cutting the hull surface, or it can be sectioned as needed to obtain the necessary data to cut frames, backbone parts, etc.
     
  6. SamSam
    Joined: Feb 2005
    Posts: 3,900
    Likes: 197, Points: 63, Legacy Rep: 971
    Location: Coastal Georgia

    SamSam Senior Member

    "Another method is to enter a table of offsets to create a set of 3D points. Once the lines drawing information is in the CAD system it can be used to create a suitable CAD model to use as input to the CNC system."
    This is what I was wondering. I assume the "lofting", or the reconciliation of minor differences, would be worked out by the cad program so the output of the cnc operation would be accurate. Thanks.
     
  7. dave2700
    Joined: Aug 2020
    Posts: 13
    Likes: 0, Points: 1
    Location: uk

    dave2700 Junior Member

    yes i am thinking of building one thanks for the help
     
  8. DCockey
    Joined: Oct 2009
    Posts: 4,818
    Likes: 370, Points: 83, Legacy Rep: 1485
    Location: Midcoast Maine

    DCockey Senior Member

    The CAD program by itself would not do the "lofting" or the reconciliation of minor differences. A knowledgable user using a suitable CAD system could do the the "lofting" or the reconciliation of minor differences.
     
  9. gonzo
    Joined: Aug 2002
    Posts: 14,735
    Likes: 756, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    The OP didn't say anything about CAD. All you need is a big enough flat surface, a few sheets of masonite, pencils, a measuring tape and a few long sticks.
     
  10. DCockey
    Joined: Oct 2009
    Posts: 4,818
    Likes: 370, Points: 83, Legacy Rep: 1485
    Location: Midcoast Maine

    DCockey Senior Member

    The OP didn't say anything about CAD or CNC. SamSam asked about input for CNC which I replied to. That is where the mention of CAD came from, not the OP's inquiry.

    Certainly a boat could and has been built from the Culler plans without a computer in sight.
     
  11. SamSam
    Joined: Feb 2005
    Posts: 3,900
    Likes: 197, Points: 63, Legacy Rep: 971
    Location: Coastal Georgia

    SamSam Senior Member

    The op asked about plans with offsets, you said it's not hard to generate offsets, I asked how you would do it and threw in the cnc possibility as it seems everyone wants to use cnc now, and was informed that yes, it's easy to generate offsets in general for manual lofting, and that a cad program has to be developed first to guide a cnc program. Thanks again, DC.

    I don't know if the Pete Culler plans above have any construction details, so if op needs those details, he should get the book mentioned here to see what might be involved. It looks to be a long term, expensive project. Three pages is not going to inform much on construction techniques, so op might need other boatbuilding books to learn those techniques and processes.

    35' 10" British Cutter | Mystic Seaport Ships Plans https://store.mysticseaport.org/ships-plans/35-10-british-cutter.html

     
    Last edited: Aug 31, 2020
  12. DCockey
    Joined: Oct 2009
    Posts: 4,818
    Likes: 370, Points: 83, Legacy Rep: 1485
    Location: Midcoast Maine

    DCockey Senior Member

    Based on what builder's expect today from plans Culler's plans for the "1840 British Cutter" might be best considered as a preliminary design. Anyone contemplating building based on those plans might want to invest in a knowledgable naval architect/boat designer doing some hydrostatic calculations, a weight and CG location estimate, and a preliminary stability analysis. Culler was better known for the look and character of his designs than being technically thorough.
     
  13. gonzo
    Joined: Aug 2002
    Posts: 14,735
    Likes: 756, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    The OP has not been back to state what he wants.
     
  14. TANSL
    Joined: Sep 2011
    Posts: 6,300
    Likes: 315, Points: 93, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    Probably what the OP wants is exactly what he asks for in post # 1. Since he has not reappeared here, it can be assumed that he has not changed in his wishes.
     

  15. dave2700
    Joined: Aug 2020
    Posts: 13
    Likes: 0, Points: 1
    Location: uk

    dave2700 Junior Member

    i just wanted to know if you could build a boat with those plans or if anyone found plans with a table of ofsets
     
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.