iMustBeCrazy

1 hour ago, Cabbie said:

Have a look at my Sampson boat co

G'Day Chris,

I've seen many of his vids, got hooked and watched them one after another. Will look again for specific lofting vids.

Edit: Just watched Lofting the Lines Part 1, the discussion on lofting starts after 17 minutes in and it seems I my understanding of those bits was right (so far).

1 hour ago, mtaylor said:

I'm a newbie at lofting also and may be wrong, but I think you need to treat the stern and bow sections separately.   

G'Day Mark,

I freely admit I'm a newbie at ships and may be wrong. Can you elaborate on 'separately'? Maybe we can work out if we're coming at the same thing from different directions.

Lets continue:

Remember those errors I mentioned? As Bruce said, you can just "ignore the differences". I chose to try to fix them.

So we now have the image in the CAD program with the shape and aspect ratio corrected.

First image is the 'uncorrected' version.

The purple lines represent the measurements taken from the Plan (top view) and Elevation (side view) these should match the measurements in the table of offsets which I don't have. On the Stern side they were pretty close (shown in the second image) but on the Bow side at station H (looks like an 'N' on this drawing) it's slightly out while station A (in green) is too wide. If I reduce the height to bring the sheer down at station H, it will be too low at station A. This is an error in the original drawing which cannot be corrected by distorting the drawing, it needs to be redrawn. Also the rabbit is incorrect at both the bow and stern compared to the elevation drawing.

This meant that I had to re-import this section of the drawing in two parts (Stern and Bow) so that I could leave the stern untouched while correcting the scale and aspect ratio of the Bow as best I can then drawing new hull lines respecting the curves where possible. The curves are a number of arcs joined by (sometimes very short) straight lines. I think one station had 5 arcs and one had 2.

.

Also remember that I really don't know what I'm doing.

Craig.

A few examples. These are the Bountys launch.

First is as downloaded, as you may see from the frame it is narrower at the top. Also the aspect ratio is wrong, the height is too short for the width.

Second has been corrected in photoshop. (but I did work out the ratios in CAD first as it's more accurate).

Third is many hours of mucking around in CAD with more to come.

All of this is just a learning exercise so I can better understand redrawing Lapwing in CAD.

Craig.

4 minutes ago, Mr. Hornblower said:

Yep, paper, pencil, eraser and a waste paper basket

Copying your image on to graph paper and drawing the new one on to graph paper will help. Otherwise draw a grid on the original.

Craig.

6 minutes ago, bruce d said:

The most promising for a quick result must be photo editing provided the subject has the right proportions to start with.

Provided you have both vertical and horizontal size references (objects of known height and width) you can resize the image using different multipliers for height and width. So a 1000x1000 image could be resized to a 1011x998 for example.

That's the easy bit, removing distortions is harder and can be impossible.

Craig.

7 minutes ago, bruce d said:

Sorry for the long answer

Bruce, (good rant) there is no short answer. Also there is always a learning curve.

Methods.

1/ Paper, pencil and ruler. Painful but works.

2/ Photocopier. Also painful but quick.

3/ Scanned image in photo editing software. Learning curve (Scaling, distorting and other things) but it works.

4/ Scanned image in CAD software. Biggest learning curve but best results.

Let us know which method you think you might use and we'll go from there.

Craig.

54 minutes ago, Mr. Hornblower said:

No worries at all Craig, we're all learning new things here

Ok, I'll share some of the things I think I've learnt.

First off your thread led me to this thread which should help you and also taught me some new things.

Second: All drawings contain errors! Measuring devices, paper distortion, copying distortion, those beers they had for breakfast etc all add to errors.

More later.

41 minutes ago, allanyed said:

Steel (1805) and the Shipbuilder's Repository (1788) list scantlings

Opps, sorry I do have scantlings for Speedy (ZAZ6426 and 6427). My brain hurts, too much learning new things.

Also apologies to Caleb for the unintentional hijacking of his thread.

Craig.

10 hours ago, bruce d said:

Have you seen this?

Thanks Bruce, but yes.

The first is a proposed 'Fancy' I think based on the lines of the 'Cheerful' but it was cancelled and a 'Fancy' was built from the 'Lapwing' instead.

The second is the 'Lapwing' with notes about the 'Fancy', 'Kite', 'Racer' and 'Sprightly' and including alterations to the interior for the 'Speedy'.

Anything online from the NMM I have (I think). What I hope for is better quality and I'd love the contract or scantling details.

Craig.

G'Day Caleb,

You've had some good suggestions above but perhaps you should reconsider the Speedy (1828), there's just more information available, including plans for a 1:100 scale paper/card model published in Modelarstwo Okretowe 22, which can be found online.

I'm on a family history quest myself about the Lapwing (1816), one of my ancestors was part of the crew when she sailed to Adelaide.

Despite having four 'sisters' - Kite, Fancy (1817), Racer and Sprightly, three 'half sisters' - Nightingale (1825), Speedy (1828) and Snipe (1828) and six 'nieces' - Vigilant (1821), Swift (1821), Basilisk (1822), Bramble (1822), Skylark and Diligence - I'm still struggling for enough good information for a scratch build.

Craig.

G'Day Guys,

Browsing my State Library web site recently I came across some high res (~6000-5000px) photographic copies of some Bounty plans you might like.

They are not quite square (slightly trapezoidal) due to the camera being offset but can be fixed in a graphics app.

Each image can be downloaded as a jpg or a ~85MB tif.

https://viewer.slv.vic.gov.au/?entity=IE5718048&mode=browse

Craig.