Le Gros Ventre by Richard Dunn - 1:24 - POF - from Ancre plans

[Richard Dunn]

Layers are not all that organised yet either, I don't work that cleanly, I always get hassled at work about it to in my professional work but meh. I prefer to tidy up at the end.

[woodrat]

On 12/24/2022 at 10:59 AM, Richard Dunn said:

Keen to hear what others who have done this build say but I am going to make a prediction, I expect the hardest part of fitting to be the fitting of the waterways and outer binding strakes to the dovetails in the top of the deck beams.

Yep. At 1:48 and using jarrah wood (too brittle) I was not able to reproduce the dovetails so I turned them into a continuous rebate. It will be hidden by the upper planks🤷‍♀️.

Happy New Year.

Dick

[Richard Dunn]

I removed the file as I was not happy with something.

[Kranck]

Hi,
Following with the greatest attention...
Did you loft the surface before designing the frame? 
I'm still pondering the options about my La Belle with Rhino (beginner though)

 

And what about CNC? Do you intend to use a 4D apparatus? Otherwise, I suppose you cannot fully mill the frame on all sides, right?

 

Best regards,

 

Nicolas

 

[Kranck]

Besides, I'd be happy to have a look at your pdf, I'm sure I would learn a lot, should you consider to upload it once more.

I followed your rhino hull lofting webinar with great interest (I mean, I DO now understand english as spoken by an australian) but I find it difficult to apply the method to round hulls, mainly because :

- Defining what a fair surface is seems to be quite difficult, as compared to more recent ships  - as such, I ssem to lose a lot of details of double curvature in some frames when I try to smooth a bit too much

- The 'knot' or error in the loft between the bow line and first station line. Not sure how to deal with that. And it does provide weird lines on that spot, which is quite logical considering the mathematical nature of Nurbs, but still annoying. 

 

 

[Richard Dunn]

On 12/30/2022 at 9:52 PM, Kranck said:

And what about CNC? Do you intend to use a 4D apparatus? Otherwise, I suppose you cannot fully mill the frame on all sides, right?

I am using CNC to cut the main parts and futtocks but not bevel, I will be doing most joints on a milling machine and bevelling like everybody else by hand.

In order to bevel I need to be able to do a 2 sided job and frankly the setup and jigging would take longer to do than the bevelling, besides I would feel I am missing out on a challenging job.
Also my CNC is temperamental and I don't want to risk the bevels and ruining my futtocks.

 

On 12/31/2022 at 12:38 AM, Kranck said:

I followed your rhino hull lofting webinar with great interest (I mean, I DO now understand english as spoken by an australian) but I find it difficult to apply the method to round hulls, mainly because :

Actually I am from New Zealand but close enough,
And yes the hull I have made is lofted from Gerard's frames, I used every 5th frame, I had no need to change any either but if you trace every frame you will get waves and unfairness just due to the tracing and line thickness.

The definition of fair is indeed different nowadays, back in the early days they were not trying to get streamlined hulls as much as just remove high and low spots, also the way the frames are shaped in old ships with that distinct array of arc  and tangents is very deliberate, if one pays close attention to the shape of futtocks that result from this formula it means that the futtocks shapes change very little from frame to frame over the middle 3/5ths of the vessel and instead the angle they meet at does, this makes it I believe possible to predict the stock of timber and ensure that futtocks can be obtained from trunks, of course at the ends they would have to use bent trunks etc but for most I personally believe that's the reason the sections have that zoned collection of arcs apparent in nearly all ships of the period.
Not the only reason but one of them.
I do not even use porcupines to fair lofts in this case, as long as I build the lofted surface with enough Isoparms to follow the shape, I think Le Gros Ventre used 30 around half girth.

Most ships now have lines that are 3 very distinct zones, aft, mid and forebody and the middle is often completely unchanged so it can be lengthened or shortened if needed .even some Catamarans I designed  for a navy oceanographic vessel years ago had a lengthenable hull I was provided with to modify.

 

 

Edited January 8, 2023 by Richard Dunn

[Richard Dunn]

I have now machined all the futtock timber stock into Quarter sawn planks, one plank per frame  750 x 50mm x 8.5mm allowing for final sanding to 8.41mm and have also cut the actual futtocks for frames 15-34.

[Kranck]

11 hours ago, Richard Dunn said:

The definition of fair is indeed different nowadays, back in the early days they were not trying to get streamlined hulls as much as just remove high and low spots, also the way the frames are shaped in old ships with that distinct array of arc  and tangents is very deliberate, if one pays close attention to the shape of futtocks that result from this formula it means that the futtocks shapes change very little from frame to frame over the middle 3/5ths of the vessel and instead the angle they meet at does, this makes it I believe possible to predict the stock of timber and ensure that futtocks can be obtained from trunks, of course at the ends they would have to use bent trunks etc but for most I personally believe that's the reason the sections have that zoned collection of arcs apparent in nearly all ships of the period.
Not the only reason but one of them.
I do not even use porcupines to fair lofts in this case, as long as I build the lofted surface with enough Isoparms to follow the shape, I think Le Gros Ventre used 30 around half girth.

Most ships now have lines that are 3 very distinct zones, aft, mid and forebody and the middle is often completely unchanged so it can be lengthened or shortened if needed .even some Catamarans I designed  for a navy oceanographic vessel years ago had a lengthenable hull I was provided with to modify.

 

 

Thanks, that is an explanation about older ships that I had never heard before. Very interesting. 

 

I think I will use a 2 sided CNC job job milling both sides of the frame. I'm interested in the process. I hope it works without too much loss of accuracy. 

But the whole job of learning rhino to drawing the frame and finally machining them is quite rewarding I think.

 

I'm still fighting with the bow now, trying to avoid the singularity, but the McNeel forums are full of clever tricks to deal with that. 

 

Good luck !

[Richard Dunn]

If you can pm me with some shots showing me the issue I will show you how to fix it, I just don't understand what the issue is yet.

[Kranck]

And what is a porcupine ? Except from the animal...

[Richard Dunn]

Porcupines.

[Richard Dunn]

By the way don't feel you have to build a hull with one surface, it seldom is done that way except racing yachts

My hull surf in bow is done like this, as long as the lines are fair and the surface tangency is tangent or curvature continuous as needed.

the smaller cuts  are a result of later work cutting the bearding line etc.
I have waterlines and buttocks update constantly to check and also in this case after the main body is lofted I will project waterlines onto front edge and manually create bow waterlines by tracing plan view into rabbet and then lofting the bow surface using curvature continuation, the forefoot patch is just a patch to fill the hole. but the result is still better than ok.
I have done this for many many ships including the Cutty Sark restoration, where the counter was a separate surface.

 

 

Edited January 10, 2023 by Richard Dunn

[Richard Dunn]

And to slow down even more I have a commission to build a model to throw into the mix.

[Richard Dunn]

Some of the Le Gros frames cut stacked on baseboard in background of second pic, but the pics here are of the static commission build I have started 3 days ago, all ready to plank and completely cut out, decks, superstructure, everything!.
Frames are 4mm Finnish 5ply,,, very stiff and wonderful to work with, the rest is 1mm ply

Note the way I tab the frames onto the build-board extension and machine the decks in , these can then be cut of later with minimal clean-up to beams surfaces.

The deep notches in beams are for the longitudinal deck stringer that form the hatch coaming sides and tie the decks together.

Below are parts for superstructure ready to assemble.

Edited February 5, 2023 by Richard Dunn

[Richard Dunn]

I don't want to star another build blog for this model as its commission and paid for but in case anyone is interested its this vessel.
A very nice subject and not too much work at 1/48  and 1760mm.

Edited February 6, 2023 by Richard Dunn

[mtaylor]

Feel free to open a log on it, Richard.  We have more than few members who do commissioned work and post logs.  

[Lubber Line]

On 2/6/2023 at 3:41 PM, Richard Dunn said:

I don't want to star another build blog for this model as its commission and paid for but in case anyone is interested its this vessel.
A very nice subject and not too much work at 1/48  and 1760mm.

Tamahine?

[Richard Dunn]

Yes
Superstructure built and hull half planked already

[Richard Dunn]

 

On 2/7/2023 at 8:02 AM, mtaylor said:

Feel free to open a log on it, Richard.  We have more than few members who do commissioned work and post logs.  

Not sure if the Client wants me to advertise it.
If it was up to me I would.
I will see if I can do just key points

[mtaylor]

16 hours ago, Richard Dunn said:

 

Not sure if the Client wants me to advertise it.
If it was up to me I would.
I will see if I can do just key points

No worries.  You don't even have to mention a "client".  But, good idea to check with them.