Lapwing 1816 Revenue Cutter

[iMustBeCrazy]

I needed a break from staring at lines on a screen.

 

Midship frame 1:24 in MDF.

 

1:24 is massive! 1:48 might be too fiddly for PoF for me, top timbers would be like matchsticks.

[Tony Hunt]

Hi Craig, fascinating thread.  One Lapwings near-sisters, HMS Bramble, is also of considerable interest to Australian maritime history (as you probably know), she served a long time on the Australia Station and did a lot of survey work in tropical waters.  Bramble Cay on the Great Barrier Reef is named after her.  Interestingly, the NMM in Greenwich has a plan showing her rigged as a schooner, and the ANMM in Sydney has an 1849 painting by Oswald Brierly showing her in the Louisiades, also rigged as a schooner and a close match to the NMM plan. But the Greenwich NMM also has a painting reputedly showing her rigged as a cutter.

 

 

[iMustBeCrazy]

G'day Tony,

12 minutes ago, Tony Hunt said:

(as you probably know)

Actually, I didn't. I haven't delved very deeply into all the sisters, half-sisters, cousins and nieces, there's too many.

 

Cutter then Schooner is the way I see it, the Cutter painting is dated 1840 and the sailplan 1841 so that works.

 

I guess I will have to investigate Bramble further.

 

[Jaager]

Post #30  - the top graphic - Body plan - aft - the new green station shape.

 

You should maybe recheck the location of the sheer point.   I see it as being too close to the preceding station.  There will be a bulge.

If you do use that shape, you may wish to leave the inside a lot fatter.  Otherwise the inside will have to have a scab layer to make it thick enough when you rasp the outer surface to get a smooth run. 

[Tony Hunt]

38 minutes ago, iMustBeCrazy said:

G'day Tony,

Actually, I didn't. I haven't delved very deeply into all the sisters, half-sisters, cousins and nieces, there's too many.

 

Cutter then Schooner is the way I see it, the Cutter painting is dated 1840 and the sailplan 1841 so that works.

 

I guess I will have to investigate Bramble further.

 

I suspect you're right - she came to Australia in 1842 as a survey vessel and served until 1859 at least. She remained in Aussie waters though, and was sold in 1876 to serve as the lightship marking the Sow and Pigs, a very well known patch of subtidal rocks right in the middle of the fairway at the entrance to Sydney Harbour.

[iMustBeCrazy]

12 minutes ago, Jaager said:

You should maybe recheck the location of the sheer point.   I see it as being too close to the preceding station.

It's certainly not final but I should have pointed out that whereas the others are every second station, as usually depicted, that one is station 15, only a single step from the preceding station (14). It's a bit of a guesstimate to try to fill in the huge gap between station 14 and the transom. Same goes for the first station at the bow.

 

If I could get out and buy some cardboard I would mock it up to get a better feel for the lines.

 

But, thank you, all criticisms and suggestions gratefully accepted!

[iMustBeCrazy]

Some sketches of Bramble taken from Owen Stanley - Voyage of H.M.S. Rattlesnake

 

 

[Tony Hunt]

Wow, they're marvelous. I hadn't seen them before. They certainly confirm the schooner rig, don't they!

[iMustBeCrazy]

9 minutes ago, Tony Hunt said:

They certainly confirm the schooner rig, don't they!

Yes. And that cockroaches can be really hard to get rid of

[Tony Hunt]

The pearling luggers used the same trick.  it must have been quite a business drying all the interior out afterwards.

[iMustBeCrazy]

Work continues, Disposition of the Frame:

 

 

[iMustBeCrazy]

Still going. Trying to work out the structure of the stern, very little info to work on. Any ideas? Any references?

 

 

Re-did the frames to include decks, it will make life easier later. I wonder, what else am I missing.

 

[Bob Portsmouth]

I would say the the timber arrangement was structurally more or less the same for the cutters? In which case it won't differ too much from Alert. There are a lot of CAD drawings either on here or Ships of Scale.

[iMustBeCrazy]

7 hours ago, Bob Portsmouth said:

I would say the the timber arrangement was structurally more or less the same for the cutters?

Thanks for those Bob, slowly piecing it together in my head but it's still mostly imagineering.

 

 

[Bob Portsmouth]

Hope it helps Craig

 

[iMustBeCrazy]

7 minutes ago, Bob Portsmouth said:

Hope it helps Craig

Well, it doesn't help my headache but it certainly helps. For one thing it shows I forgot the fashion piece. Doh!

 

Still need to rework the side counter timbers and perhaps the counter timbers:

 

 

[Bob Portsmouth]

Down to you mate, you left me behind a long time ago!! Best of luck.

[druxey]

Those counter timbers look a little thick in siding to my eye. Also as per the illustration posted above, usually the counter timbers slope slightly inward.

[iMustBeCrazy]

9 minutes ago, druxey said:

Those counter timbers look a little thick in siding to my eye

Thanks druxey, currently 8 inches, probably only need 4 or 5.

9 minutes ago, druxey said:

Also as per the illustration posted above, usually the counter timbers slope slightly inward.

I guess for even spacing top and bottom. I'll fix them.

[iMustBeCrazy]

Current state of play:

 

 

[iMustBeCrazy]

3D Transom (MDF):

 

Note that when making any part from the drawings you must make sure that the part is drawn 'square on', those that aren't such as the transom, counter, cant frames etc. need to be corrected.

For example the transom viewed from the stern appears to be 49 inches high but as shown is is actually 52 inches. To correct this, the drawing from the stern needs to be stretched vertically by 52/49ths (1.0612244).

 

Also you need to allow for any bevelling which may not be shown. In this case, the fashion pieces are wider on the forward side and the bevel is shown on the corrected drawing. Yes, I forgot the bevel the first time.

 

[iMustBeCrazy]

Well, it took two days just to draw the counter timbers and I've just moved one two inches so it now has to be totally redrawn.

 

So I've been trying to understand the yellow area in the drawing below.

 

The 'trim piece' is shown on the sail plan of the Lapwing (Danish archive) and the Nightingale. It probably extends out to the dotted line and maybe more, framing the planking.

The stern rail must blend into it somewhere somehow.

 

But the question is, what is the structure, how is it supported? It doesn't seem to overlap the counter timber enough to be fixed to it.

 

Can anyone point me to anything that might help? Or point out anything I may have misinterpreted from the drawing?

 

 

[Bob Portsmouth]

I assume the trims are for appearance only, they're reminiscent of the transoms of Yorkshire Cobles and Thonnieres and Langoustiers of Brittany where they're simply extensions of the transom boards. A look at some of those may shed a light?

[iMustBeCrazy]

8 hours ago, Bob Portsmouth said:

I assume the trims are for appearance only, they're reminiscent of the transoms of Yorkshire Cobles and Thonnieres and Langoustiers of Brittany where they're simply extensions of the transom boards.

Thanks Bob, I saw Fukui's post

just after wrote the above. It's a possibility but I'll have to draw it to see how it looks.

 

 

[iMustBeCrazy]

First, a small distraction. This morning turned out sunny despite the forecast so I snuck out down to the park for a little exercise and photography.

 

When I got back I modified my balsa mock-up of the stern/counter. It's rough but I think it works.

[Tony Hunt]

A lovely picture of a Black-shouldered Kite and a rather unfortunate mouse that has become lunch.

 

The counter mock-up looks good too!

[iMustBeCrazy]

1 hour ago, Tony Hunt said:

A lovely picture of a Black-shouldered Kite and a rather unfortunate mouse that has become lunch.

 

The counter mock-up looks good too!

Thanks Tony.

 

I think it was brunch. The same bird once caught and devoured a whole rabbit! Admittedly it was a small rabbit but still several times the size of a mouse. Afterwards it could only fly 50 metres between rests.

 

I've been having a break on the drawings as my eyes are going rectangular what with computers, books and TV. Hope to get outside again soon if the weather moderates. Old man winter seems to have arrived early.

[iMustBeCrazy]

Well, after chasing my tail around and around and around (that curve at the wale shown in post 52 can't exist) I think I'm going to have to build the stern in PoB to see what's happening. I know the outer counter timber is a straight piece of wood with a kink in it, probably leaning over towards the centreline so that the 'elbow' sticks out a bit but in 2D it's not easy to visualise and harder to draw. No wonder they didn't do detailed drawings.

 

Anyway, comments, suggestions please, I haven't done this before. This will be a fairly rough mock-up for my needs, but I still want the drawings to be useful to others.

 

Starting with the keel, bulkheads/moulds when I have done them.

 

 

[Jaager]

What research and experience has shown me:

In post #41 -  the frames from H fore to 10 aft are all bends (paired frames with alternating,  overlapped,  butt joins) .  There is a significant shift, narrowing, and air gap as they rise.  They are still paired bends.  They would have been assembled with chock lumber pieces holding the gap and the bolts and dowels that held the pair together would go thru the chock wood.  The chocks would not be a lot larger than the bolt diameter, so as not to impede air circulation.   They did not use glue, so the strength of the bend structure would be the same,  timbers touching or spaced apart.  The same as washers on a bolt.   Between the bends would have had temporary or fixed chocks too.  They may or may not have been knocked out when the planking firmed up the structure.   The cant frames forward of H and aft of 10 would have had their own chocks.  The result would not be very attractive.  Not worth showing in a model.  Little wonder that most models with visible framing from back when is at least a bit stylized.   Most old tests do not show this, but they don't show how to drive a nail either.

 

So you are going POB.  .....groan. 

 

Imagining this as POF - an obsession, I admit - I would side glue the bend paired frames and not narrow the sided dimension.  A single frame flying in the wind would be weak. End grain to end grain glue joints are not reliable and can withstand almost no stress.   A glued up bend is a strong structure.   To me, the upper - topside - above the LWL - framing structure is functional only and has all the visual attraction of the 2x4 framing in a single family dwelling.  I plank over it.  Because I hide it, and because it makes the whole significantly stronger, I fill the spaces between the bends above  the LWL with the same wood as the frames -and also glued.

Trying to figure out the join angles of the cant frames makes my head hurt, so I would frame using square to the keel bends thru M forward and 15 aft.

The hull below the LWL can then be totally planked over - with proper support for single layer planking, or partially or totally  not planked  .... for show.

Just an alternative to consider.

[iMustBeCrazy]

7 minutes ago, Jaager said:

So you are going POB.  .....groan. 

No need to groan, I'm only doing a rough PoB so I can figure out the stern. Probably only do the aft third and only plank one side above the wale. But while I'm doing that I might as well draw the extra bulkheads.

 

I will continue trying to draw all bends and the cant frames for PoF plus bulkheads for PoB. As this is largely a family history project, showing the crew accommodation is important, and PoB doesn't do that.