Hickman Sled 18 Bonus plans

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jacquesmm
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Re: Hickman Sled 18 Bonus plans

Post by jacquesmm »

The HS18 drawings are called preliminary for a reason: they do not include the same details than the TX18 but, as I write in the notes, the specs are exactly the same than for the TX18. Same plywood thickness, same type and amount of fiberglass, same stringers, same transom specs. As they exist, the HS18 plans are similar to what most designers supply as complete plans and much better than any plan based on a table of offsets.
All the information is there to build the hull but for some parts, like the stringers, you must take the dimensions from the assembled hull.
This is for the HS18, the TX18 stringers dimensions are included.

I have only the PDF version of the HS18 parts, not the 2D CAD file and if you want metric, you must do the conversion yourself.
It is easy:
- create a small spreadsheet
- enter a dimensions value and convert all fractional units to decimal inches
- apply the conversion factor of 1" = 25.4 mm

Once that is done, all you have to do is enter the imperial dimension once and it will translate automatically.
I can quickly write such a spreadsheet and would post it if there was a way to attach an XLS file to my message.

The easiest way to scale and get metric units would be to enter what you have in any CAD system, scale and convert dimensions.


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Kenfyoozed
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Re: Hickman Sled 18 Bonus plans

Post by Kenfyoozed »

The spreadsheet version is what I did wrote last night. Just need to get all the dimensions now and have the labeled as to the corresponding positions.

Is there a reason this boat couldn't be built as a sheathed strip instead of stitch and glue? Or how about making flat panels from strips and using these instead of plywood?

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Re: Hickman Sled 18 Bonus plans

Post by jacquesmm »

Yes, you can use sheated strip: cut the plywood in strips or use plain strips, plank and fiberglass.
Use more glass in the skins because you loose the strength of the plywood.
Now, with strips, you can't get the shape from the expanded plates, therefore, you need more molds but it can be done.
Or glue strips together to make a panel and use as you would use plywood.
What would be the advantage?
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Kenfyoozed
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Re: Hickman Sled 18 Bonus plans

Post by Kenfyoozed »

At this stage I was thinking that by making panels from strips that it may cost less than plywood. I also wanted to add a flare to the bow like the Tideline has. So I thought that combining strip panels for the flats areas already there but using the sheathed stip method for the flare. If there are more molds needed I assume the molds would need to be taken from the stations. Build the stations as designed then basically use battens at the chines like is done in traditional boat building. This way you know where all the points are for the chines of each mold.

Also when converting from US to metric, for example the result is 205.43. What should be done with .43, round up? down? or does it even matter?

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Re: Hickman Sled 18 Bonus plans

Post by TomW1 »

Kenfyoozed wrote: Fri Sep 25, 2020 11:01 am At this stage I was thinking that by making panels from strips that it may cost less than plywood. I also wanted to add a flare to the bow like the Tideline has. So I thought that combining strip panels for the flats areas already there but using the sheathed stip method for the flare. If there are more molds needed I assume the molds would need to be taken from the stations. Build the stations as designed then basically use battens at the chines like is done in traditional boat building. This way you know where all the points are for the chines of each mold.

Also when converting from US to metric, for example the result is 205.43. What should be done with .43, round up? down? or does it even matter?
You buy a metric tape and use it. Lowe's sells them. They are combo metric/us. You also buy the metric plans if you are going to do any scaling up. Much easier.
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

jacquesmm
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Re: Hickman Sled 18 Bonus plans

Post by jacquesmm »

Strips will not cost less than plywood. When I design the boats, I analyze the curvature and check it against the ply thickness bending radius. I count on that stiffness to create a fair hull. It is the panels that define the hull shape, the molds play a secondary role, mostly of support.
In strip building, the shape is set by the molds. With insufficient molds, the strips will sag between molds, for that reason, you need more molds.
Even with plywood, you can create some flare. That flare will be purely aesthetic, it will not improve the running of the or the spray deflection.

In metric, round up to 1 mm.
On my plans, I set a dimension tolerance of 1/8" = 3mm. If I draft metric plans, that tolerance will be 1 mm but the HS18 is in inches only.
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Re: Hickman Sled 18 Bonus plans

Post by Kenfyoozed »

I've been playing around trying to develop this hull in delftship. But having a hard time getting the bow fleshed out. Anyone have any tips?

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Re: Hickman Sled 18 Bonus plans

Post by jacquesmm »

My plans should developed panels. Why do it differently?

There is no magic software for developing panels. I worked on that since 30 years and was a beta tester, in that field, for several CAD companies. Not one is perfect but the closed one is the cone methods from Orca 3D. It is tedious and requires a good feel for 3D geometry. You also need Rhino 6, total cost of softwarer is close to $ 4,000.00 and still, there is no guarantee that you will be able to get the result you want.

https://orca3d.com/

Somewhere on that site, they show my JA18:
https://orca3d.com/pages/gallery

Again, I did the work and I show the developed panels in the plans but, if you want to experiment, I can't help you with Delft, I never used that program. Do a search on Youtube, I think there is a Dutch designer that developed panels in Delft.

If you want inexpensive software to model in 3D and develop panels, look at Nautilus from Newavesys. I used it many years ago. It is good at developing but there is a very steep learning curve. You have to enter a compounding allowance for each material, that mean experimenting, testing. Nautilus cost about $ 300.00.
http://www.newavesys.com/
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Kenfyoozed
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Re: Hickman Sled 18 Bonus plans

Post by Kenfyoozed »

i wanted to build in 3d as it is and then scale it 10%. A few other topside tweets that i wanted to play with like the sheer line.....

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Re: Hickman Sled 18 Bonus plans

Post by jacquesmm »

OK, that makes sense.
How about getting a trial version of Rhino? I think you can save a few times without paying for the license. Or do a screen copy.
Once the model is created, type "devsrf" and follow the prompts.
Devsrf is not on the standard command list but it works OK.

I checked Delft: you can develop plates with Delftship Pro. It cost only 150 Euro, much cheaper than Rhino but again, I can't help you.
Most yacht designers use Rhino.

More: I found this:
https://www.boatdesign.net/threads/deve ... els.28896/
go down a few posts and there is a method listed for Freeship.
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