CNC cutting lengths needed for various metal sailboat hull designs

Discussion in 'Sailboats' started by cadmus, Dec 11, 2014.

  1. cadmus
    Joined: Mar 2009
    Posts: 65
    Likes: 0, Points: 6, Legacy Rep: 10
    Location: USA

    cadmus da boom hit'um 1ce 2often

    I am very lucky to have married into a family with a very large CNC watercutter and plasma cutter. It would have been better to marry into enough money to just buy a PREBUILT boat but I will take what I can get ;)
    I have been trying to estimate cost associated with said equipment. This is a function of time which is a function of material (Al vs Fe), material thickness and linear cutting length. Can anyone provide me with linear cutting distances for each material thickness for any medium to heavy displacement 32-42’ sailboat hulls. If just framing or part of framing or plating that is fine, just specify. I plan to build aluminum but steel would be fine info also, I can estimate the scantling change. Yeah, I know this is heavily dictated by the design I want to build but that will be debated over the next few years. BIG error bars are fine on this estimate. I am just getting a feel for this cost of this part of the build process. I have years before I can commit to a design. But I know what types of hulls and types of construction will increase or decrease this cutting distance and I can estimate up or down and put big error bars on my estimates. I have tried to find this info (or cutting files) for common (kit) boats, Pratique 35, Dix 32 & 34, Fay 32, 36, 40 & 44, some metal multichine version of the Endurance 35, trisbal, trismus, standts… many others. But, I have found nothing and I can guess why. Any help is appreciated. Feel free to guesstimate.

    (EDIT: i list these designs because i know numerous people have had Dix boats and Fay boat framing and plating water cut. I am open to anything of similar length and displacement)
     
  2. gonzo
    Joined: Aug 2002
    Posts: 13,932
    Likes: 481, Points: 93, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    The manual for the equipment your family has will give you the information. It is not possible to guess what speed it can cut without knowing the make and model, the alloy type and thickness. It can be from 1 inch/hour to feet/second.
     
  3. Mikeemc
    Joined: Nov 2014
    Posts: 71
    Likes: 1, Points: 8, Legacy Rep: 17
    Location: South Carolina

    Mikeemc Junior Member

    We have a water jet cutter too depends on what material your cutting.
     
  4. cadmus
    Joined: Mar 2009
    Posts: 65
    Likes: 0, Points: 6, Legacy Rep: 10
    Location: USA

    cadmus da boom hit'um 1ce 2often

    No... i am asking for the cutting lenghts of various designs.

    No. I am not looking for info on the watercutter speeds. I have that. AND I can adjust that depending on how nice of a cut I want.

    I am asking if people, who have CNCed frames, plating or everything on aluminum or steel sailboat builds (as described in the original post) can report how many linear feet of cut at each metal thickness were involved with the design they built and the parts (if not all) that were CNC cut.
     
  5. TANSL
    Joined: Sep 2011
    Posts: 5,898
    Likes: 231, Points: 73, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    I have much information about that for many ships: number of parts in each, cut length, void movements, etc. But everything depends on the type of vessel under consideration and the structure has been designed for the same. If you could give me more data, I will gladly help.
     
  6. pdwiley
    Joined: Jun 2008
    Posts: 1,002
    Likes: 86, Points: 48, Legacy Rep: 933
    Location: Hobart

    pdwiley Senior Member

    Why bother? Honestly, the cutting time/charges are going to be such a tiny proportion of the overall build cost that what you're doing is akin to straining gnats while planning on swallowing a camel.

    I cut all my plate with a $600 plasma cutter.

    PDW
     
  7. cadmus
    Joined: Mar 2009
    Posts: 65
    Likes: 0, Points: 6, Legacy Rep: 10
    Location: USA

    cadmus da boom hit'um 1ce 2often

    TANSL,
    Thanks for the offer to help, I will send a Personal Message shortly.

    PDWILEY,
    you said: "Why bother? "
    I really do not feel this cost is insignificant. I am not wealthy or careless enough to enter into a project without having cost estimates and time estimates of all parts of a project and a measure of my error. Even if i agree your statement that this monetary cost is trivial I need to ask myself how long will it take to cut a full boat worth of framing and plating? I can not cut into the factory's normal functions so i will be working at night, living with the in-laws, and skipping my work responsibilities. Also, i might hire the cutting out to a more local shop at a higher cost but save my time and freight? Quotes from local shops would be based on the same factors: cut length for each metal thickness.

    What is unacceptably sloppy is that i am asking for this information for ANY sailboat design of length and displacement similar to those listed above. Vague. I know. It is kind of a catch 22. I can only derive this value myself by digitally lofting a design, I can only do that buy BUYING the full plans and building rights, but I would not purchase stock plans or commission plans without first knowing the construction costs. So having a few examples will help narrow down the decision.

    Thanks,
    Pete
     
  8. gonzo
    Joined: Aug 2002
    Posts: 13,932
    Likes: 481, Points: 93, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    Ask your inlaws. If they are running a business cutting metal, all the data is already available to you. Anyone claiming to be able to provide any figures will have to get access to the data your inlaws have.
     
  9. pdwiley
    Joined: Jun 2008
    Posts: 1,002
    Likes: 86, Points: 48, Legacy Rep: 933
    Location: Hobart

    pdwiley Senior Member

    I'm afraid that you're screwed. That information isn't likely out there and it certainly can't be generic.

    Take 2 examples - a single chine hull basically comprised of flat plates. You can work out pretty easily the length of cuts for the deck edge, bearding line, chine line etc. Butt joints will depend on the size of sheets you can buy and handle. Frames can be easily estimated - they're all straight lines and a lot of them will nest inside others. So it's pretty simple to work out. I could do it for my boat if I had to, but I'm not going to measure it up, too much hassle.

    Second example - a compound curvature round bilge hull. Good luck working this one out in advance. Or at all as plates need to be rolled in an English wheel or similar to develop the compound curvature. Suffice to say there is a hell of a lot more butt joints, more and smaller plates, and correspondingly lots of welding to glue it all together again. Frames are equally demanding to make.

    In between there are multi-chine designs, radius chine designs etc etc.

    Honestly, if your budget is going to be so tight that you need to consider in fine detail the cost of cutting the plate - don't build. Life is going to be hell.

    If you build out of steel, have you factored in the cost of blasting & priming, or can you buy blasted & primed plate from the steel merchant? The cost of blasting & priming is going to be many, many times the cutting cost.

    There are lots of steel & a lesser amount of aluminium boats out there. If you want to go sailing, buy one. There is no sense in building your own unless you really want to build a boat, in which case, seriously, you're concentrating on a trivial expense when you should be looking at much bigger issues (like blasting & priming). If I can cut all the plate for a cost of $700 or so - plasma cutter & consumables - for a 12m steel sailboat, I suggest you do the same or use a figure of say $1000 as the max you'll pay to have it done professionally because over that, you can do it yourself cheaper.

    Please don't advance the 'it saves time' argument - if you wanted to save time, you'd buy a boat.

    PDW
     
  10. TANSL
    Joined: Sep 2011
    Posts: 5,898
    Likes: 231, Points: 73, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    There are many people "able to provide figures without having to get access to the data your inlaws have".
    I totally agree with pdwiley regarding that information depends largely on the type of boat and the type of structure. Obviously, a transverse structure take many more parts cnc cutting than a longitudinal structure composed largely of extruded profiles.
    If you indicate me the boat you are studying, we can define the type of structure, scantlings and we can make a correct estimate of the number of pieces and cut lengths. The cutting speed for each material and thickness, is the user of the cutting machine the only one who knows.
    This is what I can offer. I enclose three examples of information that my system generates.
     

    Attached Files:

  11. bpw
    Joined: May 2012
    Posts: 291
    Likes: 4, Points: 18, Legacy Rep: 34
    Location: Cruising

    bpw Senior Member

    He is asking how many feet of cuts are needed for a sailboat hull, this has no relation to the equipment used, and unless his in-laws build boats they will have absolutely no clue.
     
  12. DGreenwood
    Joined: Aug 2004
    Posts: 719
    Likes: 38, Points: 28, Legacy Rep: 507
    Location: New York

    DGreenwood Senior Member

    Usually if you buy the bid package, you can estimate the cutting footage with a batten and a scale ruler. It won't be perfect but you can get pretty close. Frames are the toughest but a little math and some guesswork will put you within 5% of actual. I would think if the designer has that info he would share it with you. Did you try calling them?

    As someone pointed out, the change in cost for this part of the work has to be an almost undetectable fluctuation in the spending stream for a boat build?
     
  13. cadmus
    Joined: Mar 2009
    Posts: 65
    Likes: 0, Points: 6, Legacy Rep: 10
    Location: USA

    cadmus da boom hit'um 1ce 2often

    Thanks for the replies. I had family visits for a week then field research for a week and had no internet.

    pdwiley, i agree with everything you say but have no clue why you would discourage someone from investigating this cost.

    DGreenwood, I have asked designers. they said nothing or said "i should have that info, let me look into it"
    I have not purchased any building rights or plans at this time. You are right, i could estimate it or get it perfect by lofting it if i have decided on a design i like but at this time I have not.

    I am surprised this is not information widely posted when designers are trying to sell stock plans. Material lists and cutting lengths do not divulge information about the design but allow buyers to plan.

    bpw, correct. thanks.

    TANSL, Many thanks for the information and offer. I will send a personal message soon.

    Thanks,
    Pete
     

  14. pdwiley
    Joined: Jun 2008
    Posts: 1,002
    Likes: 86, Points: 48, Legacy Rep: 933
    Location: Hobart

    pdwiley Senior Member

    I'm not really trying to discourage you from investigating the cost, I'm saying that the cutting cost is trivial, noise level, in the overall costs of building a boat. It simply doesn't matter. You will spend far, far more money on paint alone than you will getting plate cut. So in effect you're straining at gnats while planning on swallowing a camel.

    For designers with CNC cutting plans they could probably work out the edge lengths but this limits your choices to designers with CNC cutting plans (and those who can be bothered). This is a subset of all plans and for the older boats there's no way they're going to work this out on the off-chance that you'll buy a set of plans off of them.

    I've done this, for a single 12m long boat admittedly, so I know how long it takes & how much it costs to cut the plate up. The only way I can see it working well getting it CNC cut is if you buy a complete pre-cut kit of all frames and hull plate in one go, and that's not what you're talking about here.

    Think on this - if you didn't have access to family run cutting, would you still build a boat and would you still care about the cost of cutting plate? Pick a design that you love and buy those plans. Everything else will fall out in the wash. Budget 5 years for the job..... and one further bit of advice - make sure you have a fully enclosed workshop to build in. It's miserable working outdoors, everything slows down. I built my shed before I started on the boat and it was sized to make boat building easy.

    PDW
     
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.