如果已经完成，你可以节省自己的时间不必要的努力 - 除非当然像我一样，你喜欢绘制船体！
如果它不存在，您很有可能会找到类似的东西，您可以将其用作起点 - 将新数字放入现有的和类似的偏移表远比从头开始更容易，至少从头开始。
计算> Rescale> Length Overall（全部更改）
我们现在可能需要改变我们的小艇的比例，因为试验和测试的规则规定了梁和干舷。在这一点上，我转向一本由John Teale编写的有用小册子“如何设计小船”的图表，并由Adlard Coles Nautical出版。（约翰·泰勒也是一位经常和有趣的英国“经典船”杂志的贡献者。）
（尝试不要双击，因为Hulls会要求您键入新的X，Y和Z坐标，如果发生这种情况，请勿单击取消 - 这使得软件认为您的意思是X，Y和Z都为零并立即将您的合理绘图变成废话，如果发生这种情况，请回到上次保存的版本，我相信格雷格会很快就把这个小问题放在正确的位置，如果在阅读之前还没有这样做的话）
从另一个减去一个我得到一个24.8in的干舷数字，而从约翰·泰勒的图表，我真的在寻找约19in。现在，你可以选择一个特别高的弓 - 无论我去哪里，我看到那些无耻地打破了泰勒先生的规则的船只，而且有一些流行的设计，高弓，以应付粗糙的水域。不过，我尊重泰勒先生的判断，我认为我会按照这本书重新调整最大高度。我会通过将最大高度降低5.8in来实现（即，旧的干舷图减少新的）。显然，这将重新缩小船上的每个垂直维度，但是让我们来看看我们的感受。你现在可以预期的是：
我可以在水线上增加梁，注意从弓到船尾产生甜美的曲线。从约翰·特雷（John Teale）的书中，我收集到的最大光束通常是水线光束的1.1到1.2倍，但像这样一条小负载的水槽可能会被破坏。 我可以增加船的总长度，比如说六寸。 最后，我可以选择从Teale先生的书中打破另一个规则，并扩大船体，再次使用Rescale最大光束。 在这种情况下，我选择后一种选择（我做出了正确的选择吗？谁知道？），并发现6号车宽阔的船减少了我与中国人和艉板的关系。记住，要扩大6in的船，你只需要添加3in到Rescale Beam图。
现在这艘船的船尾有一个可爱的斜坡。通过平衡它，我可能只是把艉板从水中拿出来。这一次，我们使用偏移表来解决问题。我转到数据菜单，然后单击偏移表。这看起来不像传统的偏移表，但并不是太难以遵循 - 只要记住，X是你所看到的一半的光束，Y是高度，Z是距离杆的距离。
在这种情况下，我可以通过确定船尾的Z坐标全部为132in，然后点击“完成”按钮，从而使船尾伸直。从侧面看，我可以看到，一个小小的调整将使艉板完全脱离水面，仍然产生一个公平的曲线。所以我把船尾和下一个小河的平底移动一下。这变得越来越好 现在，位移曲线告诉我，水线上升到艉板的最底部，水中最上方只有很小的数量。大。但现在bouyancy的中心再次向前迈进。哈！ - 这意味着在船尾部的框架中的梁的更多的调整。所以我这样做 我从来没有说过这是一个简单的练习！
在这一点上，我的好奇心让我看看这艘船的稳定性。但是在这里我必须发出一个小小的警告 - 在执行此操作之前将Auto-spline Chines设置为ON，因为在我的PC上，可爱的旧Hulls完全破解并崩溃，而不让您保存。我已经失去了几张图纸。
在这一点上，当然，我真的不知道你的小艇的细节，这自然会与我的不同。然而，从我看来，我可以看到，11ft可能太短了，因为一个真正的干燥小艇设计为承载一个这样大的负载。如果我再次开始，我可能会选择一个常规的婴儿车，或者在弓上有一个窄的横梁。从我所看到的，我也建议，如果你的意思是在任何地方排列或拖动这个水槽，这将是值得给它一个skeg，将有助于跟踪相当好 - 究竟应该是多大的是一个审判的问题并且错误，但从其他船只看这个大小，面积约一平方英尺，给或采取一点，不应该太错了。使它从船尾跑步，从船尾三英尺处，并以船尾结束，
DXF输出设备在对话窗体中，我也可以点击扩展，DXF和文本。当按下保存时，这些将分别告诉软件将开发的面板以CAD标准.dxf格式保存，如果您有一个3-D CAD软件包（将在计划中显示为图形），则会以三维生成.dxf图像并以2-D包装提升），并输出一组坐标，可以在使用板条铺展之前将其标记在单板上，然后切割 - 至少比正确的放样更好！
这里我要补充一个重要的警告。赫尔斯所生产的坐标在造船方面是传统的。然而，赫尔斯有一个错误，产生了像12-8这样的坐标。解释为13-0。有一天这可能是固定的; 直到那时，不难生活，但你必须了解它！ .dxf输出的一个非常重要的用途是确保复杂多线工艺的船尾和弓形横梁真的是平坦的。从Hulls输出文件，使用CAD软件包进行检查，如果需要，请返回并修改。当然，你可以通过毕达哥拉斯几何来完成所有的事情 - 如果你喜欢用可以更好的方式修复的小事情。
输出偏移我还没有尝试过，但是我收集可以输出使用Hull产生的偏移量的ASCII文件。您安装通用/文本打印机驱动程序。然后，选择我的电脑/打印机 - 然后单击添加打印机。选择GENERIC并安装驱动程序时，选择打印文件选项。要使用，只需右键单击GENERIC / TEXT打印机图标，然后在启动Hull之前选择默认值，并将偏移量保存到您选择的文件中。当然，在退出Hull之后，您需要右键单击常规打印机并恢复其原始默认设置。
Gregg Carlson's Hulls program
an alternative tutorial
The 7ft10in hull
Return to boat design home page
Hulls is a great program. It has given me hours of fun and helped to deepen my understanding of boats, and before going any further, I would like to thank its developer, Gregg Carlson, for making it freely available.
This tutorial takes you through part of a design process for a general purpose 11ft stem dinghy in order to illustrate Hulls' features.
To my mind, the first step is to check that the hull you are interested in has not already been drawn and in the Hulls format, *.hul. You may be surprised at what you can find in what Gregg calls his inspiration list, which includes a soft-chine plywood Laser-alike, and a Munroe Egret, which goes by the filename of 'Derby'. There's also my own small collection at http://home.clara.net/gmatkin/design.htm .
If it has already been done, you could save yourself hours of needless effort - unless of course, like me, you enjoy drawing boat hulls!
If it doesn't already exist, you are very likely to find something similar, which you can use as a starting off point - putting new numbers into an existing and similar offset table is far easier than starting from scratch, at least to begin with.
By 'similar', I mean something with the same number of chines, and the same sort of bows and stern. For example, if you wished to draw an 11ft dinghy with a flat bottom and two chines, you might wish to start with one of my drawings '7ft10in.hul' (pictured above), which you should be able to pull down easily from my Web pages area using the following URL:
http://home.clara.net/gmatkin/drawings.htm This file is a good start, even though it's shorter and fatter than the shape we are setting out to develop here.
Having used Hulls to open this file in the usual way, give the file a new name and save it straightaway to avoid the possibility that you might over-write the original. When I did it for the purposes of writing this alternative tutor, I called mine 11ft.hul.
The next task is to extend the drawing to 11ft, or 132 inches. This is made easy in Hulls using the Calculations menu:
Calculations>Rescale>Length Overall (Change All)
Enter the 132in figure for 11 feet, and RETURN. The result will look exactly the same as before, for while the given dimensions of the drawing have increased, the proportions have not changed in any way and the program fits it into the available screen space as before.
We probably need now to change the proportions of our dinghy, as there are tried and tested rules governing beam and freeboard. At this point, I turn to some graphs published in a useful little book, 'How to Design a Boat' by John Teale and published by Adlard Coles Nautical. (John Teale is also a regular and interesting contributor to the superb British magazine Classic Boat.)
According to Mr Teale, a reasonable beam for this dink would be about 4ft 6in or so, presuming a waterline length of just under 11ft. So, accordingly, now we make the beam of our dink 54in. Go to the Calculations menu again:
Calculations>Rescale>Maximum Beam Only>
And enter the figure 27in to produce a total maximum beam of 54in. You'll notice that this makes the planned dinghy a little less beamy.
Now it's time to think of that bows freeboard figure. Here Mr Teale suggests a figure of 1ft7in or so. But this time we can't simply rescale the maximum height, as the whole thing turns on how much water the boat is displacing. My guess is that this boat will weigh about 100lb (this is based purely and simply on another boat of similar stitch and tape construction, but you can check the numbers later) and with, say, three adults weighing 200lb each, we quickly come to a huge-looking displacement figure of 700lb.
Clicking on the top lefthand view will give you a view along the bows to stern axis of the boat. Using the Calculations menu again, enter 700lbs:
You will observe that the water level rises to just kiss the chine. In order to keep wavemaking and general fuss to a minimum when travelling through water, I have read that it is wise to make sure the waterline does not rise above the chine at the design load. I think the writer was referring to hard chine boats in particular, but I suspect following the same rule won't do any harm here.
We can't go ahead and adjust the bows freeboard yet, as I can see a problem that will materially affect the displacement results we've just been looking at: it is that the lower part of the transom is under water, and will cause wasteful turbulence as it moves.
So I would start to work on fixing that by looking again at the stern-on view. Select the blue line denoting the stern frame, left click on the lowest chine of the hull and pull it upwards to the 700lb waterline.
(Try not to double click, as Hulls will then ask you to type in new X, Y, Z co-ordinates. If this happens DO NOT click cancel - this makes the software think you mean that X, Y and Z are ALL zero and instantly turn your sensible drawing into nonsense. If it happens, go back to your last saved version. I believe that Gregg will put this minor problem right shortly, if he has not already done so by the time you read this.)
Also raise the point at the left of the screen, where the centre line of the boat meets the flat bottom of the hull. the bottom must curve front to back, but as plywood does not take kindly to being forced to take compound 'tortured' curves, let's keep things simple by keeping the bottom flat from side to side.
Then click on the side view. To be frank, we've produced an ugly underwater shape, and so will have to think about raising the bottom at the third frame as well. To compensate for the loss in bouyancy, and given that we need this dinghy to carry 700lbs efficiently, I would then widen the body of the hull at both the stern and the third frame slightly. Boats intended for use with an outboard and/or for carrying large loads have to have wide sterns in any case.
Now let's have a look at that bows freeboard figure. Again from the stern view, I find that in my drawing the water level is at 7.5in, while the overall maximum height (at the bows) is 32.3in (though by now your drawing will be different, and increasingly all your own!).
Subtracting one from the other I get a freeboard figure of 24.8in, whereas from John Teale's graphs I'm really looking for about 19in. Now, you might choose to have a particularly high bows - wherever I go I see boats that shamelessly break Mr Teale's rules, and there are popular designs that have high bows in order to cope with areas of rough water. However, I respect Mr Teale's judgement and I think I'll follow the book and rescale the maximum height. I'll do this by bringing the maximum height down by 5.8in (that is, the old freeboard figure less the new one). Obviously this will rescale every vertical dimension in the boat, but let's do it anyway and see how we feel about it. As you might now expect it's:
Calculations>Rescale>Maximum height only>
In my drawing, I insert a new maximum height of 26.4, and then look again at the displacement situation by asking the software to recalculate the waterline at 700lbs. The good news is that I'm still happy about the overall form this boat in many ways, but the bad news is that I've still got a stern that's in the water, and the waterline is now above the level of the chine. What should I do now?
There are at least three choices that I can see:
I may consider that these things don't matter too much, and do nothing. That's ok, so long as I'm not looking for this boat to row like a Thames skiff.
I could increase the beam at the waterline, taking care to produce a sweet curve from bows to stern. Again from John Teale's book I gather that maximum beam is usually 1.1 to 1.2 times the waterline beam, but in a small load-carrying dink like this rule could perhaps be broken. I could increase the overall length of the boat by, say, six inches. And, finally, I could chose to break another rule from Mr Teale's book and widen the hull, again using Rescale Maximum Beam Only. In this case, I choose the latter option (Have I made the right choice? Who knows?) and find that widening the boat by 6in overall reduces the problems I'm having with the chine and the transom. Remember that to widen the boat by 6in, you have to add only 3in to the Rescale Beam figure.
I also widen the flat bottom slightly at each frame from bows to stern. The displacement calculation says that I've still got some transom and chine in the water, but by now I'm prepared to rationalise and say that it probably won't carry three 200lb adults all that often, after all.
Now look at the side and plan views. The side view now shows me a sheer that I don't care for too much. Knowing that a sweet sheer can usually be obtained by making sure that the sheerline is straight for the first third of its length, comes to a minimum a little abaft the halfway mark, flattens out for a bit and then rises cutely up to the stern. Fiddle with it for a while until it looks good to you, but remember that a little dinghy like this will need to have a health amount of freeboard amidships.
In the case of my drawing I'm also a little unhappy about the centre of bouyancy, which is just about halfway from stem to stern, and I know that John Teale says it should be a little aft of this point. This time, I click on the plan view and move the second, third and fourth frames slightly towards the stern. This also will make the bows section far easier to make because the ply will not have to curve so sharply.
I also further widen the flat bottom and the adjacent chines to produce fair set of curves, and look again at the way the bottom curves. I have read Uffa Fox, and understand that to give this boat a fair chance of planing (with an outboard, obviously!), I have make sure that the deepest part of its 'chest' is about a third from the bows. I do this by deepening the second frame slightly. This is probably best done in the stern to stem view. Do look at it from the other views too, to ensure that the curves continue to be fair from each angle.
Now it's time to look again at displacement. What do I see? There is still a trace of transom in the water, Dammit!
Now, the stern of this boat has a cute slope. By squaring it off, I might just bring the transom out of the water. This time, let's use the offsets table to fix the problem. I go to the Data menu, and click on Offsets Table. This does not look like a traditional offset's table, but it's not too hard to follow - just remember that X is half the beam at the point you are looking at, Y is the height and Z is the distance from the stem.
In this case, I can straighten out the stern by making sure the Z co-ordinates in the stern are all 132in, and then hitting the 'Done' button. From looking at the side view, I can see that a small tweak will bring the transom out of the water altogether, and still produce a fair curve. So I move both the flat bottom at the stern and the next chine up slightly. This is getting better. Now the displacement curve tells me that the waterline rises to the very bottom of the transom, and that there's only a tiny amount to the uppermost chine in the water. Great. But now the centre of bouyancy has edged forward again. Hah! - that means more tweaking of the beams in the frames in the after part of the boat. So I do it. I never said this was a simple exercise!
At this point my curiosity leads me to look at the stability of this boat. But here I must issue a small warning - leave the Auto-spline Chines set to ON before you do this, as on my PC poor old Hulls goes completely crackers and crashes without letting you save. I have lost a few drawings that way.
Given its form, this hull should be highly stable, and I can find out exactly how stable by going to Heel on the Calculation menu. This tells me that at 15 degrees of heel, and with its weight evenly distributed about the boat, my little vessel would have an impressive-sounding righting moment of 383 foot-pounds, but this is a fairly academic figure in a boat this size, as trim will depend on the passengers moving as required.
Finally, if we were interested in making this dink sail, we might like to consider adding side decks to provide a comfortable sitting out position. We can do this by adding a chine.
Again, let's use the offsets table. I use the Chn slider bar to add a fifth chine, and then hit the offsets table button. First I make the Z co-ordinates for the fifth chine in each frame the same as its sisters lower down the frame. Then I make the height (Y) of the fifth chine the same as the height of the fourth at each frame. I can add a camber later if I want to. Then I make the width (X) at each frame three inches less than the maximum beam at each frame. (Except at the bows, of course!)
I also make the rabbet line of the stem lie back into the boat to form a small deck area. If I place the final chine offset about 20in from the bows I get a result I think is beginning to look sensible - but which but makes the deck very narrow in parts. I fix this by adjusting the fifth chine at the second frame.
By this point, of course, I don't really know the detail of your dinghy, which will naturally be different to mine. However, from looking at mine, I can see that 11ft is probably too short for a real stem dinghy designed to carry a load as large as this. If I were to start again, I would probably opt instead for a conventional pram, or something with a narrow transom at the bows. From what I have read, I would also suggest that if you mean to row or tow this dink anywhere, it would be worth giving it a skeg that would help it to track reasonably well - exactly how large it should be is a matter of trial and error but, from looking at other boats of about this size, an area of about a square foot, give or take a little, should not be too far wrong. Make it run from, say, three feet from the stern and allow it to end with the stern, round it off, and attach a metal strip for protection.
Three dimensional modelling Pressing the CD button at any time produces a three-dimensional view that can be moved around using the X, Y and Z buttons at the top of the screen. Also, if your HTML browser has a VRML add-on, pressing the VRML button produces a three-dimensional object in that format. I've tried it, but it was very, very slow on my 90megahertz computer with 40megs of ram and I don't bother now, as the wireframe view that the CD button produces works well.
Developing the panels This is possibly the most impressive feature of Hulls. Go to File Save, and take a look at the dialogue box. There you will find scads of useful buttons to press, and criteria to input. Place up to eight structural frames where you like. I suggest for our 11ft dinghy, you might like to choose three or four and distribute them reasonably evenly. Some of these will handily double as walls for built-in bouyancy.
If you change your hull model and wish to nest a new set of developed chines, as you might do if, for example, you wanted to fit the panels for a whole craft onto a limited set of sheets of ply, it seems to help to save the new form, and close Hulls and then reopen it and your file to ensure you are nesting the correct panels.
DXF output facility On the dialogue form I would also click on expansions, DXF, and text. When save is pressed, these will respectively tell the software to save the developed panels in the CAD standard .dxf format, produce a .dxf image in three dimensions if you have a 3-D CAD package (which will appear as a drawing in plan and elevation in a 2-D package), and output a set of co-ordinates that can be marked out on sheets of ply prior to being faired with a batten and then cut - at least it's better than proper lofting!.
Here I have to add an important warning. The co-ordinates that Hulls produces are in eights, as is traditional in boatbuilding. However, there's a bug in Hulls that produces co-ordinates that read like this 12-8. Interpret this as 13-0. One day this may be fixed; until then it isn't hard to live with, but you have to know about it! One very important use for the .dxf output is to ensure that stern and bows transoms of complex multi-chined craft really are flat. Output the file from Hulls, check it using your CAD package, and go back and amend it if you need to. Of course, you could do the whole thing by Pythagorean geometry - if you like fiddling about with small things that can be fixed in better ways..
Buttoning on Patterns>Nesting produces a handy gadget that allows you to nest the developed sheets onto up to five 8 by 4ft ply, and Save here produces the co-ordinates you asked for earlier.
Outputting offsets I haven't tried this, but I gather it's possible to output ASCII files of offsets produced using Hulls. You install the Generic/Text Printer Driver. Then, select MY COMPUTER/ PRINTERS - then click on ADD PRINTER. Select GENERIC and when installing the driver, select the PRINT TO FILE option. To use, simply right click on the GENERIC/TEXT printer icon and select as default before firing-up Hulls and saving the offsets to the file of your choice. Of course, after exiting Hulls you will need to right click on your usual printer and restore its original default setting.
What else can Hulls do? If you've got this far, I honestly think you'll find the rest of Hulls' features fairly self-explanatory. Try them out!