“Twenty five feet, three tons on him”
Quote, Captain Quinn

Let us know when you will be releasing the film. 😉

Not only a great model but the comprehensive details of the build has been very entertaining as well as amusing. I just hope that the RSPCS don’t hear about one of their fish/animals being so cruelly mutilated.😂😂
One thought I had was will the towing vessel be up to the job in bad weather or will the shark rebel and go its own way?
Rogal thanks for the entertainment regards ChrisG

Looking good,

Yessir...

Made a start to get jaws sitting right in the water, decided to go for it and started by disemboweling him with the dremel. Then formed the lead sheet into 3 blocks and took the weight it read 1.8kg so I thought I would start at that weight rather than be under and have to add small extra pieces. The first task was to fit the lead blocks in the slot on the sharks belly, I stopped these falling out using cocktail sticks pushed into the foam each side of the slot. Doing this enabled me to right the body without the lead blocks falling out, he was then laid in the bath tub water. As can be seen in the accompanying photo he sank too low in the water, so I trimmed the lead blocks down a tried again, perfect just right, so back to the bench I packed the sides of the lead with foam to hold in place and placed a strip of wood over the slot then mixed filler and covered over. Then sanded the belly smooth and water tested again. Spot on, job well done, if I say so myself. Total finished weight 2.2kg he quite a heavy chunky guy, you would think he would sink to the bottom but floats very stably. Just the live test at the pond to go now, tomorrows out though as 20 mm of snow is forecast locally and I can’t find my snow shoes. House bound then.

Not surprised your brain hurts! mine hurts and I am on the side-lines. 😂😂😂 ChrisG

Hi Rogal,
We'll have a whip round to get you a bottle of Original Taste.😉
Can't recommend Diet Coke. Not much real difference in calories and various studies indicate adverse health effects from the synthetic sweeteners used.
Apart from that it tastes bl***y awful and makes terrible Cuba Libre😝

"If I used the whole internal volume as a ballast tank I would loose the buoyancy of the foam, catch 22".
The mass of the foam involved is negligible compared with 1.6kg.
I don't think that would make a significant difference Rogal. Remember, it's the submerged volume that accounts for the displacement, and swim depth. So I don't think that Captain John Yossarian's psychological problems are applicable here😉! (Yes I have seen the film and I have the original hardback book by Joseph Heller.)

You have already proven that you need 1.6kg to get Jaws to float where you want it to.
Add a few grams to compensate for the loss of the interior foam if you wish but I wouldn't bother. Mass involved is negligible compared with 1.6kg.
More important is most likely the angle of incidence of Jaws' lateral fins.
So I totally agree with Andi1, until you try towing Jaws to see if he swims, dives or porpoises you are working in the dark. A negative (downward) angle will force him under, a positive angle will force him to surface. Possibly causing him to leap above the surface (depending on the speed) and diving back down again, i.e. porpoising . Ditto repeato! Would be fun to watch though😀 But perhaps not what you are looking for. So aim for neutral incidence, i.e. horizontal.

My recommendation would be to go with ca 1.6kg (140-145cc) lead within the body.
Would either need 4 more slots like the one you have already made.
Or one plug of 4cm diameter by 11.25cm length.
Much easier to accommodate than 1600cc of water👍
Which would need a cylinder of about 10x20.5cm.
In most boating lakes a false bulb under the ventral will be visible when near the shore and detract from the visual effect and swimming - added drag! Also when on display on shore. Aggro mounting and demounting! We don't want to give away our little secrets do we?😉

Your problem reminds me strongly of a similar snag I had with my 1/72nd scale dynamic diving Type 1A U-Boat, from Krick LoA 107cm.
Built according to instructions she floated too high, despite two 6V 4Ah SLAs, dive planes were still above water☹️
Just like you I draped weights over the hull 'til she floated right.
Then milled hull compartments fore and aft to accommodate corresponding weights of lead.
Hull construction was 'bread and butter', i.e. 4 planks of 2cm thickness.
On sea trials the dive planes would still not push her under but just threw up huge 'moustaches' of water. Spectacular but not exactly true to original😐
I then did some research at the Deutsches Museum here in Munich, where U-1 is on display with the starboard hull plating removed to expose the interior, and bought a helpful book about U-Boat designs, with scale plans. This told me that the Krick dive planes were too small.
So I made a new set. Still to be trialled as most unfortunately shortly thereafter U25 suffered a severe collision with the workshop floor😮😠 Subject for a future Blog😉

Bon chance mon ami🤞looking forward to your progress reports / trials videos👍
Schlaf gut!😴
Cheers, Doug😎

My brain hurts!, I’m going to bed early night.💤💤💤

Hi Chris,
I'm not a biologist, much less a marine biologist (my biology and chemistry teachers and I reached a mutual conclusion that it would be better if we amicably parted company and I devoted the thus freed up time to my strengths; physics and applied maths, with German and English Lit/Lang on the side.)
So I don't know how fish and other aquatic creatures manage that. A question of scale and evolution I suspect. They are mostly more concerned with pressure equalisation I would think. Implosion at depth or explosion near the surface would be most unfortunate.💥

No, I took the simple pragmatic engineer's view.
As soon as I read Rogal's post it struck me that a mass of 1.6kg of water would occupy a volume of 1.6lt or 1600cc.
This immediately called to mind my 1.5lt bottle of the said Coke on my bar (used for my Cuba Libre😋😋), which I measured. Length 10" (25.4cm), excluding tapered part of the neck, mean diameter 3.5" (radius 4.5cm).
Volume of a cylinder is V=πr²h. Thus V=(22/7)x4.5²x25.4cm³. =1615.87818cm³ (cc).
As near as dammit 1.6lt. The rest of the Coke is in the tapered neck of the bottle.

The largest recorded white shark is 20.9' (6.4m) a female!
Now I don't know how big Rogal's shark is but at 1/16th scale the big mamma would be about 40cm long. Alas I can find no data on the girth of such a monster munching machine.
Interestingly the females are generally larger than the males. EEK😮
Male great whites on average measure 3.4 to 4.0 m (11 to 13 ft) in length, while females measure 4.6 to 4.9 m (15 to 16 ft).

Comparing volumes of other potential ballast materials is a simple matter of dividing the volume of 1.6kg of water by the relative density of the other material; e.g. lead 11.34 g/cm³.
Required volume thus being 1600/11.34=141cm³. much easier to fit to the model shark.

Hope that clarifies my dumb engineer's thinking for you Chris.
Cheers, Doug😎

Rogal! I knew it! We think alike. 😉

And yes, it does not have the presence of your sculpt!
Damn the torpedoes and full steam ahead with the ballast tests. 😀

If jaws is emptied out, but sealed up again he would still be bouyant

Good evening Fleet, thanks for your input, I’ve just raided the piggy bank, I don’t have enough even for a 1.5 Ltr. Bottle of Diet Coke so it looks like water. Earlier when I was contemplating my options I thought about the weight to volume needed and know a gallon of water is 9 lbs and needed about a 1/3 rd of this. I thought the size of my shark is similar to a 1.5 ltr. Bottle which would weigh about right too. If I used the whole internal volume as a ballast tank I would loose the buoyancy of the foam, catch 22, there’s more to this than meets the eye, back to the drawing board. Another thought would be to add a false detachable bulb keel that wouldn’t be seen under water. Anyone has thoughts on this one??. Regards Roger.

Hi there jumpugly, I purchased this kit just to help me with the sculpting of my model, to get the proportions of the fins to body near enough correct, and with the body shape. The shark cage in the kit was modified and used on the deck of the Orca and tied up in loose sections as in the film before being erected and used. Here is a photo of both sharks the kit one doesn’t have the presence of my attempt and is a little small. It was extremely helpful in a lot of other ways though, so was worth the purchase price. Thanks for your thoughts and encouragement.

If you ever have get away from your beautiful sculpt, which I hope you don’t, you could consider the Pegasus Hobbies Great White kit. However, it is in 1/18th scale and thus could be entirely moot. Besides, I like the water ballast idea! 😉

Hi Rogal. A static waterline is one aspect so more weight will be needed a ballast tank is an option too, but I still think he needs pulling to see what he does, I've never made a shark so trial and error.

Hello Doug
This is interesting and difficult for me to get my head around, is the problem because of the material the shark is made of which has a high buoyancy level, subs and many mammals and fish use water to retain their preferred level in the water without looking excessively pregnant, why should this model be different?
This is not me doubting your expertise but my need to know and understand.
Thanks ChrisG

Hi Rogal,
Don't like to be the bearer of bad news (please don't shoot the messenger!)
But I don't think that'll work with water☹️ unless you want to make the shark look like it's pregnant with sextuplets!
1.6kg of lead (density 11.34 g/cc) has a volume of 0.141lt. (141cc)
Water (density 1g/cc) would have a volume of 1.6lt. (1600cc)
About the size of a 1.5 lt bottle of Coca Cola Original taste.😮
To reduce the volume further you could try the following (assuming that you win the lottery)-
Tungsten or gold, density 19.3 g/cc; volume 83cc, 🤑🤑 Gold €65 / gram.
Total cost ~€104.000.
Tungsten less than $1 / ounce, (28grams) but about about €25-30 or more when processed, i.e. into usable sheet / blocks. Total cost €48.000 (a bargain😁😂)
Osmium, density 22.59 g/cc; volume 71cc. 🤑🤑🤑🤑🤑 €1350 / gram.
Total cost €2.161.000.

An interesting conundrum, need to go lie down in a dark room to cogitate that🤕
BTW: What size is the shark; LoA and mean diameter?
Cheers, Doug😎

Hey I like the idea of water ballast what is good enough for the Royal Navy should be great if tailored to a model shark, which is a credit to you. The more you consider the options the more ideas come to mind, the choices are boundless, well done.
Regards ChrisG

In need of help and inspiration,Any ideas. A dull and rainy crap day in Doncaster today, wife out shopping, dogs snoring stretched out on sofa, so I have just filled the bath tub with water to test float the great white shark jaws. What a shock I got, it floats ok but I’m afraid too well. There is only about 15mm in the water, the rest is bobbing about above.Before glassing the foam I cut a slot in the belly and inserted strips of lead weighing approx a pound(1ld) or .4kg, I thought this ballast would help “ sink” the body enough. How wrong could I be. I’ve just laid some more lead sheeting over the floating shark and to get to the desired waterline that looks right I will have to add another 3,1/2 pounds or 1.6 kg which is hefty lump of lead. at the moment it is in 3mm sheet form, but I could melt I’d down and cast a solid lump!. To a shape to fit inside the body, then I just had a thought, what about water as in a submarine’s ballast tanks. If I fitted a bottle inside I could fill with water at the pond side and empty when going home. Am I rambling? What ideas / suggestions do you guys have before I disembowel this shark?

Hi jumpugly the scale is1/16th i bought the plans from patrick tittle of Alberquercue New mexico. At the time a source couldnt be found in UK. Cost about 30$ inc post etc.
Thanks for your interest.

Rogal! I was just curious, what scale is your Orca?

Fantastic detailing Rogal. Well done. I've turned quite green ! 😉

Brilliant! Looking forward to a video!😊

Great work, I'm excited to see how the team performs on the water. Keep it up.

Great job 👏 , I certainly am not as gifted when it comes to sculpting, however I did manage to find an oversized dolphin which became a suitable donor for "Bruce's " dorsal fin. I made a suitable keel and then attached this via a suitable coupling and rod to the stern of my Orca. Add the barrels and looks OK. Presently back in the dry dock due to the esc burning 🔥 out in mid run. Fortunately no further damage. When I get chance, I intend to look at placing the barrels out from to try and imitate the "nantucket sleigh ride". Hopefully you'll find a way to attach "Bruce ", looking forward to the next installment 👍

Firstly what you doing awake at this hour? You could ensure they are a 'foiled' shape to give a certain amount of lift at a certain speed so on calm water behind your boat far enough away from prop wash/draft effect for stability, he glides along nicely.
A more complex idea could involve a gyro mounted in jaws so the lateral fins change angle depending on tilt each fin could be controlled by a separate servo and two gyros so jaws would automatically adjust to maintain even straight flow, both vertically and horizontally, obviously he's a fun idea and you may not want to go that far, but just passing my thoughts on I love the 'odd things' I've sourced some wood for my IngaIV masts, recycling scrap using old Victorian washing rack lathes if they are ok to use🙂

Hi Andi1. that’s the next challenge, I have thought about the aqua dynamics of fixed fins in water on a model shark, and toyed with the idea of mounting on a linked shaft so I could vary the angle as the maiden voyage testing progressed.but then realised there are to many other factors, like buoyancy, speed,ballast,wave conditions. So said bugger it, just set it fixed to start and don’t get too technical. Trial and error see how it goes. Although the worst that can happen is a sudden nose dive on acceleration. We will see, a steep learning curve!, or should I say diving curve. May be a total disaster, turn turtle etc but if you don’t try you will never know, and it’s such fun trying, Watch this space, video to follow.

Orcasome, neat idea have you pulled jaws in water yet? Just wondering if the fins incidence in the water will lift or dive him? And what speed will he handle? Look forward to a video of them in action🙂

Great clip of the film must have watched it twenty times , it’s great for the details of the barrels,rigging,cabin, deck, figures etc.just realised to, that the net swinging inside the cabin above the stove is still in my bit box unfitted!. There’s always something to add to previous models when re looked at. Well something to do tomorrow.Thanks for everyone’s interest.

This is Fantastic Rogal!!!!!

Tow line attached to a harpoon in his head and a 'Minion' barrel Roger😁😁😁
😎