SimonBrown

3 hours ago, terryb said:

I recall it was quite a haven for wildlife, but it seems to have cattle grazing now, with most of the shrub and trees gone.

Its a brilliant place for wildlife. The cattle help graze the heath, keep the shrubs and trees suppressed and lets the lowland heather heath exist. Shows how nature really abhors a vacuum, and I reckon those rounds you speak of are just under the soil.

There are the remains of two target trackways in the ranges. I will nip over there again and get enough images for a 3D model now I have the GPS marks.

I too would love to see any old photographs of it in action.

Well I took a ride out...went looking for the which house complete with its diesel engine and managed to get hopelessly lost and in a bog...I did cross the bed of where the railway once ran but except for an earth bank there was not much to see. Worth a look along the entire length perhaps to see if there are any remains?

Short story: did not find the squiggles, knew I was faced with 18kms of headwind on the return so bailed the search. 

At some point I will go back and have another look, as well as get a few images of the diesel engine that sits in the winch house. It might make a lovely 3D model.

I really have no idea how I managed to create duplicate entries?

I will put the keyboard down and check out those shapes.

By the squiggles do you mean these:

https://www.google.co.uk/maps/place/51°16'04.7"N+0°41'14.4"W/@51.267977,-0.6887742,461m/data=!3m2!1e3!4b1!4m6!3m5!1s0x0:0x0!7e2!8m2!3d51.2679768!4d-0.6873375

Make sure you are in satellite view to see the shapes.

If the ranges are open I will take a ride over there and find out, but I suspect they are scrapes put there by the wildlife people. They strip off what little topsoil there is and it provides a window of opportunity for species that like that environment.

5 minutes ago, Adrian Barrell said:

Strangely enough, the 4" Mk V naval gun is a likely candidate. A first war gun using separate loading ammunition but by WW2 was used as a high angle AA gun with fixed ammunition.

Well that is not as daft as it seems! Naval guns we know something of, but knowing they were repurposed as high angle AA makes a lot of sense.

Many thanks for this - much appreciated.

Some more images of hold number 4. First up, an overview of the contents. Note the crates of 4in shells on the right hand side...there is a lot of bang left on this wreck:

Hold 5 overview

Note that originally this hold would have been rectangular. The force of the explosion is apparent.

Now some detail. I have expanded the image to show the suspect torsion bar:

Hold 5 Centre

The trolly is in the lower right corner.

At the forward end, there is another pile of possible torsion bar/axle remains. A view of these would be most welcome:

Hold 5 Forward

Any opinion or thoughts on these would be, as ever,  most welcome.

David - I think you are right. Worked at 43 Command Workshops in the past and yes we had those very things. Now convinced I was 'over thinking' what the trolley could be...its...a...trolly!

I will have a deeper look at the structure you refer to - that would be amazing (but not impossible) if we can ID another vehicle from a torsion bar covered in marine growth. Many thanks for this.

Following on from the work in holds 1 & 2, Alex and I are starting to look at what might have been carried in holds 4 and 5.

Hold 4 has sustained the most damage, to the point that around 30m of the ship is now missing. We have identified 3 Universal Carriers, plus some very shattered remains of other vehicles that may be beyond ID - just diffs, wheels, tyres etc plus an engine block. The bomb  landed in this hold and the subsequent fire ensured the ammo functioned. We will return to this area of the ship later.

Hold 5 has fared better. I have generated a high resolution image of the hold and its contents. To say things are jumbled is an understatement:

A view of hold 5

Which has triggered a few questions that the forum may be able to assist with:

Does anyone recognise the small 4 wheeled trolley to the right of the image in the link above? The front and rear wheels appear to be differing sizes, and I have put some measurements on to assist. Note the top of the trolley has a distinctive circular feature? We do know there are aircraft starter trollies in the cargo plus fuel tankers and aircraft spares. This trolley may be airfield related.

There are boxes of shell cases lying in the hold, plus individual shells around the wreck. They are marked on the base plate "4in Mk V" along with a plethora of stamps and one is dated 1927. Does anyone have an idea what sort of gun these shells would have been intended for?

Finally, one of the wheels is fitted with a tyre that looks very rounded - like an aircraft wheel perhaps? Any thoughts or clues on this would be welcome...I do realise there isn't much to go on, but you never know.

If anyone needs a measurement to assist then just ask. The main/master image is at a scale of 1mm per pixel and is GPS referenced, so anything can be directly measured with confidence.

Look forward to hearing what the forum thinks. Best of luck...some of the stuff has 70+ years of marine growth...

This thread jumped off the screen this morning.

The SS Thistlegorm has three of these vehicles in the holds - see http://hmvf.co.uk/forumvb/showthread.php?43658-Thistlegorm-vehicles-mistaken-identities for the background to the story.

From the list of vehicles stored in the holds, we were missing a contemporary BY5 FBE example. None appeared to have survived.

Until now.

PB1954RS I have dropped you a PM.

The good news is the owner of the Morris Commercial CS11/30 rang me yesterday. Even better news is he lives less than 10 miles away, so a visit will be arranged very soon.

Now, in the intervening years, has anyone restored an Albion BY3 Bridging Variant?

There are three examples in the holds: One visible and two buried under debris. We are very confident of the two buried examples - their rear load deck is quite distinctive and the parts we can see measure identically to the visible example. With the 3D model scaled and geo referenced we have no immediate need to dive and measure anything...we can measure the model directly.

Great images Simon.

 

Are there any fundamental differences in techniques for underwater scanning? Other than the obvious (such as waterproofed electrics/electronics!), does laser light require relatively clear water, similar to that needed for good visibility?

 

Tony

Hi Tony - its all done with a DSLR, albeit one in a waterproof housing rated to 60m, plus some waterproof flash guns. The technique involves shooting hundreds or thousands of overlapping images that are then stitched together to understand where common points exist in 3D space. The software knows the sensor size, the physical characteristics of the lens and what points are common, and from that some some witchcraft-like calculations (sometimes taking days) to figure out how the points relate to each other. Bang in some known scales and GPS points and you get an accurate model, good to measure from, print or derive something called a DEM and termed an Orthophoto - see these links:

http://deep3d.co.uk/2017/04/07/ndac-orthophoto/

http://deep3d.co.uk/2017/06/25/the-art-of-dem/

http://deep3d.co.uk/2017/06/08/geo-referencing-the-ub-116/

Visibility wise, the further you can see the easier it becomes. Worked in some very dirty water at Port Royal, Jamaica, for National Geographic earlier in the year, but proved it was possible - just needed a lot more images.

Pete Gaine has recently restored a Morris CS11/30 Ambulance. Currently advertised for sale on Milweb.

Now that is great news - thank you Simon.

I don't post much here, but feel its a good time to wake this thread from its slumber.

For those who don't know me, I'm an underwater photographer that creates 3D models of underwater subjects. Back in the last century I completed my Apprenticeship at 43 Command Workshops REME, so military vehicles really are in the blood...I digress...Regular readers may remember the NDAC models I shared a while back:

https://sketchfab.com/simonbrown/collections/submerged-military-verhicles

This summer I have been working as a Visiting Fellow at the University of Nottingham with a specific mission: To scan the wreck of the SS Thistlegorm and its cargo. It has taken months of work, but there will be a press release very soon announcing just what has been covered and achieved.

Alex Mustard (original starter of this thread and key chap behind the research as to what cargo is really in the holds of the wreck) and I have been chatting about the results and he mentioned there were a few gaps in the surviving vehicle types - most notably the Morris-Commercial CS11/30.

In the intervening time does anyone know if an example of this vehicle has turned up? Anything been found/restored since?

Many many thanks Dale. Those measurements are perfect to verify the model.

Given a bit more time, I have had a chance to reprocess some more data, and have merged the two models into a single view:-

https://sketchfab.com/models/d283a1efb9b6411d8224a1b3b62dc546

This is how they lie in the quarry today, with a British Aerospace Jetstream 200 alongside for good measure.

I'm going to send some diver friends off to measure the actual distances and compare to the model.

Thanks for the ID Dale.

What makes it stand out as a command post?

I have been out diving and scanning again, this time it was the Alvis Saracen now sitting in 15m of water at the National Diving and Activity Centre near Chepstow.

Does anyone know the history of this example?

Link to the resulting model:-

https://sketchfab.com/models/24e69ec0191e4bafae89d2cc62ff7de0

That is truly excellent, so you do not have to actually measure anything at all when you gather the data! Do you think that the time to gather the data this way is comparable to doing it by measurements for what is quite a complex shape?

In the case of the Dolly (And the Stalwart) I took a few key measurements between the control points we placed before the scan. You can see the control points on the Stollie load bed - white squares with black targets printed on them. For the Dolly, two measurements along the length of the hull, one across the stern and one from deck towards the keel were recorded and used to scale the build.

What you do not have to do is take hundreds of measurements. To measure the curves and recreate the hull shape of the Dolly would be very time consuming. Underwater its even worse as we have a time limit of gas supply and (if deeper) decompression stops.

So we can take a very complex shape and scan it. Things that cause real issues are anything with a lack of texture (no points to detect), any reflective surface like glass (ditto) and anything that moves between frames (schooling fish and swaying seaweed).

Purely as a matter of interest, could the data from this kind of imaging be used to create a model using a 3D printer?

Like this?

http://deep3d.co.uk/2016/03/31/dolly-varden-model/

ABS model sitting on my dining table as I write. The Dolly Varden is currently under restoration, so we scanned it beforehand, as a record of the "as is". The control point measurements were used during the build of the model to add real world values to the alignment of the images.

And the original scan:-

https://sketchfab.com/models/94305ff714b2451eb40591e821a2a438

I have not measured the physical model yet to check scale - I simply told the printers to "Print it in one go as big as you can" and its about 280mm long.

Next step will to be print in metal.

Hope this helps?

Just as the latest results from a photogrammetry dive completed, this thread popped up. So it seems a good place to share another 3D model of a now-submerged ex-military vehicle:-

https://sketchfab.com/models/a490b319654b425d8b636140599f103d

This Stollie is now resting in 15m at the National Diving and Activity Centre. It was sunk as a diver attraction and not lost as a result of an engine flood...

I would have thought that vacuum forming a replacement item ought to be feasible. That method would also have the advantage of being insulated. You would need an original to make a mound from initially.

Or scan an original using photogrammetry and then print direct to plastic?

Here's an example of a small component that has been scanned:-

https://sketchfab.com/models/f6d74a38063a49c08ebdfc6f32e6f21a

And printing directly to ABS (good for 100 degrees or so) has already been done with other parts. It will not look like Bakelite, but given its a repro is that a problem?

I would be interested in giving this a go on a fuse cover.

simon i thought you were going to tell me about the all singing all dancing sonar you tow behind your boat but looks like you did it the hard way, fair play to you fella.

I wouldn't even pretend to know much about sonar, save as to reviewing the results and having a guess how many cannons/anchors are on the site.

But yes, multibeam sonar can generate models. But the costs are - I believe - prohibitive for individuals, and you do not get a true colour render like the AFV432 example.

The Shipwreck Project is where all this photogrammetry kicked off (http://www.theshipwreckproject.com) from, and we are looking at ways of doing a 3D scan without putting a diver in the water, but it won't involve sonar.

Those 3D models are amazing!!

Thank you.

simon those images are amazing, how do you do it ?

Many thanks. Glad you liked the models.

A quick summary would be something like this; learn to dive & survive, gain experience, learn to manipulate a camera and light underwater, dive when the tide and underwater visibility is in your favour, shoot hundreds or thousands of images, process said images into a 3D model...but there is a lot that can go wrong...the underwater world is entered at risk, the conditions vary from being able to see perhaps 10m (in Studland Bay) to not seeing your hand in front of your face, the use of flash guns underwater cause issues, knowing what the camera can do and works best at takes time, kit can fail to work, the resulting images can have issues that mean they won't align and build a model...the list goes on.

And to get real detail, you need a lot of images. Valentine Tanks numbered 1 & 2 had around 450 images per tank, and tanks 4 & 5 were treated to around 800 images per tank.

I covered the aligning, building and meshing step in more detail when I scanned the yacht Dolly Varden:-

http://www.dollyvarden.co.uk/restoration/3d-modelling/

The mention of Valentine Tanks in Studland Bay was how I came to find this forum, so I thought I would share some of the underwater scans I have made of the tanks. Be prepared to weep, they are not in great shape...seawater and Royal Navy EOD has seen to that:-

https://sketchfab.com/simonbrown/folders/valentine-tanks-of-studland-bay

I have also scanned an AVF 432 hull that has been dumped in a quarry to act as a diver distraction:-

https://sketchfab.com/models/bb16a8d1eb304a32b0382f202d47e307

As for the Centaurs off Selsey...well nothing is impossible but I suspect the preservation costs would outweigh the not insignificant recovery bill.

Hello all.

My interest in military vehicles really started at a place called Long Valley in Hampshire way back when the development of Khalid & Challenger was underway. I could hear the tanks running from my house, and would bike over to the test track to watch them.

I went on to do a four year MoD apprenticeship, learning vehicle repair skills on everything from Can-Am motorbikes right up to Challenger MTB and everything in between. I still have a soft spot for Stalwarts and Ferrets...but the thought of changing a bevel box reminds me why I don't own one.

Shipwrecks and underwater aircraft crash sites are another interest, and being a professional diver/underwater photographer I have documented quite a few losses.

The current area of interest is photogrammetry - using hundreds or thousands of still images to rebuild physical 3D objects. Here are a few examples of the Valentine Tanks of Studland Bay:-

https://sketchfab.com/simonbrown/folders/valentine-tanks-of-studland-bay

3D printing is the next logical step and I have sitting on my desk a printed model of one of the cannon sites that is just off Chesil Beach. A second print is underway of the oldest vessel on the register of historic ships:-

https://sketchfab.com/models/94305ff714b2451eb40591e821a2a438

The model of the Dolly Varden, as she is known, has been scanned and built to scale and is measured accurate.

I have been thinking about using photogrammetry to recreate parts, where the original exists but is worn or no longer serviceable and using the scan in conjunction with 3D CAD to remanufacture certain components. Or scanning an entire tank and getting it printed in bronze...the possibilities are endless...maybe your mate has a much needed part but won't sell so why not scan it to scale and get it made?

Anyway, thats me.