yes i know but then they can take the guns and the other parts from that ship and go to the format that is close to them
If I got a nickel for each time somebody told me what I wanted to do was impossible... well, you get the picture. Having a background that includes experience with computer cooling system design, aircraft aerostruture design and high performance car design has shown that me that it's never impossible with things like this; it's just a matter of whether the cost in time and money is worth enough to somebody to warrant expending enough of both to develop a finished product. I'd like to point out that if we were to figure out a destroyer next, we'd be the ones that would have to figure out how to make the design work well from wood, with allowances for build variation. Gascan, should I count you in alongside mike5334, katori87 and myself for this combined effort on the Emile Bertin?
That's a pretty safe bet there, especially considering how my lil' bro Gascan lives just across the hallway from me, and we spend almost as much time talking about this project offline as we do posting about it online [] I am still pretty hesitant about the Emile Bertin. It's significantly bigger than most of the other ships we've been looking at. It's closer to 600 feet than 500, while most of the other ships are in the 400-500 foot range, and it displaces at least 2000 tons more. I would be worried that whatever layout we come up with for the guts, we would not be able to transfer into other ships. On the other hand, if we were to design for a Tashkent, Capitani, Mogador, Gearing, or similar ship, it would be much easier to transfer the basic design and guts into another similar-sized hull.
The key drawings that we're going to need to work from are 1, 2, 8, 9, 10 (all in 1/100 scale but should be verified by measuring a small section printed out); a few of the others with more details may prove useful too. For example, drawing 7 shows all of her external rigging, firing arcs, etc. For anybody who may be following along, the information we're referring to may be found at the following link: Visit this site Keep in mind that these are huge if you try printing them out; they're all several feet long and about 20" or so tall.
I figure we may as well begin with the Emile Bertin despite its larger-end size at just over 48 inches in length. While it's not quite the size target we originally envisioned, the source data is readily available and it's suitable for sorties from both sides. Since it is on the larger end, even we get a little more leeway with how well we execute the design. I'd like to look at it this way; since we're starting with a larger vessel that isn't much of a challenge for us to design well, we'll have one definite product from this before we go chasing a design that may take longer or (hopefully not) meet a less than entirely successful conclusion.
I thought I made a post, but I must have thought I submitted it when I closed Firefox. If we're all happy with the Emile Bertin, we should start figuring out the next step. We need to compare big gun and fast gun rib spacing and hull construction rules. What are overall dimensional tolerances, how much depth can we add, do we want to flatten out the bottom? For every 1/8" of rib thickness (up to 3/8"), big gun clubs require at least 1" of space from the inside edge of one rib to the inside edge of the next (that is different that center-to-center spacing). We also allow up to 2" impenetrable area (measured at the waterline) from the bow and stern. I believe Fast Gun has stricter rules for bow and stern penetrable area, so could we check that out?
From the 2008 Edition of the MWC Rules book 2. The total hull length that can be solid material shall not exceed 15% of the overall length of the hull. This includes ribs, solid material at bow and stern, and fillets. Measurement shall be made along the longitudinal centerline of the model (farthest point forward to farthest point aft of hard area). a) A rib or keel shall be defined as any solid material attached to the hull skin, which is perpendicular to the plane of the waterline, and whose function is defining the shape of the hull. b) Ribs and keel can be no thicker than 3/8" thick material. c) Minimum spacing between ribs shall be no less than 1" from rib centers. d) Solid material in the bow may extend no more than 2” aft following the contour of the bow. (See Diagram A.) e) Solid material in the stern can extend no more than 1" forward, following the contour of the stern. 3. The main deck(s) may be no more than 3/8" thick (maximum thickness of any single or multiple deck assembly). 4. Impenetrable material may be used as hull skin, but must be at least 1" below the waterline or more than 45 degrees down the turn of the bilge. (See diagram B) The hull skin immediately around the prop and rudder shaft exits may be impenetrable material; it must not, however, interfere with the inherent penetrability of the hull.
The rules across the board seem to allow 2% variation with the potential for a little more allowable variation in fast gun so I believe that's what we should target being able to achieve. For the purposes of easing the build, we probably should flatten a portion of the bottom; however, my opinion is that part of it (towards fore and aft) should more closely follow the prototype hull form to try an preserve some of the hydrodynamic efficiency of the design. I also believe that we should make provisions for the bilge keels to be made from 1/8" plywood or a similar material, although it will be up to the individual builder whether or not to utilize them. All that I see regarding ribs is that a maximum of 15% (of 48.39") may be impenetrable, leaving us a total of 7.25" (assuming I haven't made any mistakes) for ribs and impenetrable hull at the bow and stern. If we assume close to the maximum of 2" impenetrable at the bow (which would be following the bow contour) and close to the 1" maximum at the stern, along with 0.25" ribs, I think we'd have 17 ribs that would need to be spaced out with 2.5 inches between each pair of ribs. Anybody from the fast gun side of the community out there who could verify this?
The numbers almost work out good for 19 1/4" ribs with 2" inside to inside spacing and 3" bow and stern impenetrable. Unfortunately, that is 16.01% of the length of the ship. Even if we go 2% longer than scale, it is 15.70%, which isn't legal. The same is true if we go with 12 3/8" ribs. Total impenetrable area for 2% oversize is 15.20%, which is illegal. If we drop one 3/8" rib (11 ribs) or two 1/4" ribs (17 ribs) and increase the average spacing, we can meet the 15% rule.
I'd be fine with either of the configurations. I think I'd prefer 17 1/8" ribs myself, but I'll allow those with more experience to make the decision of how many we go with.
If you alternate 1/4" and 3/8" ribs you still need to use the 3" spacing required by the 3/8" ribs. I prefer to use all the same thickness of wood. I like 3/8" aircraft ply, but I'd like to take a closer look at how close the ribs would be to the ribs provided by the plans. Of course, if we make a CAD model, we can be sure that the hull will be smooth and have nice curves. The problem with 17 1/4" ribs is that you need to cut out more ribs and you have to clean off more ribs every time you reskin, and I hate scraping ribs clean. On the bright side, you only need two thicknesses of wood if you go with 1/4" ribs: 1/8" decks and 1/4" subdeck and ribs and keels.
If we make this as universal as possible, we'll use the CAD data to interpolate ribs for a wood hull while the solid model data could be fed into a rapid prototype machine to make a plug for a fiberglass hull. (-:
in my humble and oh-so-unbiased opinion, fiberglass is for the folks who don't know how to build wood. Actually looking at it, the drawings so conveniently provided by the French gov't look to be perfectly set up for a Big Gun ship with 1/4" ribs. And they've got the horizontal and vertical sections as well, so we can technically figure out any other ribs we may need without having to use CAD. The only big benefit to CAD-modeling at that point is to assemble the various hull parts and plan out how components will fit in.
The main reason I would rather still want to generate a CAD model is to be able to provide exact, dimenioned templates for each part such that there are files that intrinsically retain their dimensions (whereas an image file depends upon the interpretation of pixel quantity into dimensions) and could be used to laser-cut wood sheets into the various parts. Since it looks as good as it does though, what do you think then if we see what happens if we just use some image editing to render ourselves a preliminary set of templates so somebody can assemble a hull to offer some feedback on the dimensional quality? If we do this with keel construction, we can create the kit plans off the existing drawings; all that would need to be done as new work would just be to denote the width of the slots in the keel and the ribs for them to interlock during assembly.
Well, it also saves having to carve the more complex bow and stern sections. Another thought I have toyed with is having a CNC router carve the impenetrable bow and stern sections (all the stuff with the complex curves in a wonky stern below penetrable as well), then a wood kit, with those bits, is a lot less daunting to a newb. Or do it in 3 major bits - the impenetrable areas, and add ribs and caprail. The "solid" bottom could have the water channel and rib notches carved in by the CNC Router in a 2 step process. Just thinkin'. I am really looking forward to Techshop coming to Texas this summer. Cheers,
oNE OF YOU NEEDS TO ORDER A TASHKENT KIT FROM BDE. I THINK IT IS 30.00 BUT IT COMES WITH ALL LAZER CUT PARTS AND THE EXACT CAD LAZER DRAWINGS THAT THE PARTS WERE CUT FROM. IT WOULD GIVE YOU A WONDERFULL INSITE INTO HOW TO DO A BULK RUN SHIP.I WENT TO KINKOS AND HAD IT BLOWN UP 50% AND NOW I HAVE A 1/96 TASHKENT THAT WENT TOGETHER LIKE A NICE PUZZLE. ASK WREO ABOUT HIS KIT
I've seen photos of the Tashken laser-cut kit; the easiest way for us to be able to execute a similar kit (and the 2D CAD that would be necessary for the company doing the cutting) for the Emile Bertin would be to digitize the profiles of the ribs and work from there.
