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Command Boat 90

Scratch built at 12th scale from pictures and profiles of the internet. The boat was originally built in Sweden a class of fast military assault craft originally developed for the Swedish Navy by Dockstavarvet Speed: 40 knots (74 km/h) Draught: 0.8 m (2 ft 7 in) Length: 15.9 m (52 ft) Overall; 14.9 (48') Complement: 3 (two officers and one engineer); Up to 21 amphibious troops with full equipment Armament: 3 × Browning M2HB machine guns; 1 × Mk 19 grenade launcher; 4 naval mines or 6 depth charges . The Model I was attracted to this boat due to its great performance and maneuverability, this was mainly due to the use of twin water jets as the main propulsion, this is a trade off with efficiency. So my start point was to collect as much information as possible about the boat this involved collecting pictures and profiles of the craft from various sources. http://www.dockstavarvet.se/products/combat-and-patrol-boats/combat-boat-90-h/specification/ Eventually I found some plans of sort :- http://laurell.today/boats/combat/plans.html My Dad was a boat builder in the days of wooden yachts, and had showed me how to make plans and frames from a line drawing. I went about this first by creating a prototype about 24 in long out of light ply. I then created full size plans of the model to be made. Pictures of small prototype finally painted plain green. The Main model Used my computer to print out the frames onto paper, cut them out and used them as templates for the ply ribs. The construction was simple chine style, with 1.5 mm ply. I tried to build jet drives but failed to produce a effective unit. So reverted to propshafts which worked out well with better control and the boat can spin on it own axis by putting one engine in reverse the other in forward and adjusting the twin rudders. That it for now, hope it was of some interest

6 years ago by CB90

Directory

(Racing Boat) Tearinto

Toy converted to brushless great fun, fast and furious (Motor: 5000kv etti) (ESC: Joysway) (10/10)

6 years ago by Biscuit

Forum

Darby One Design hydro...

Very true, there isint a lot of interest in speedboats today. I remember some great ones when I was a child in the late 1950s and early 60s. I once saw an Albatross on a lake in Scarborough that was towing a water skier in 1959. I believe that is was made of aluminium instead of wood but it did have an inboard engine. . Another one I remember was the Dowty Turbocraft powered by a water jet driven by an inboard petrol engine . This was on the Southport Marine lake in 1961 and attracted a lot of spectators. it is up to us as model makers to keep the memories alive by what we build and sail. Boaty😎

6 years ago by boaty

Forum

Tony O

Like all clubs, the price of kits and alike! And the same people doing maintenance on jetty’s and rowing boat plus ground maintenance. The members dropped to only a hand full and I think the lake we used, permission was stopped due to new owners.

6 years ago by Jerry1

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SuzyQ

Thanks, i think i make a Water Jet or Z-Drive on the bigger modified boat, thats my idea

6 years ago by Dampfgerd

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54 year old Crash Tender

Sort of! All done with Giant Duplicolor spray cans! 😉 Nearly shook me 'and off 😲 Yep. learned about the diaphragms! They were a bit tricky to balance but made a hell of a difference compared with the crappy standard Solex. After crunching the Minx on black ice in Thetford Forest 😡 I took 'em off and put them on a Triumph Herald. That and gas flowing the motor ins and outs bumped her up from 75HP to about 125 😊 Getting the needles and jets right was the trickiest bit. Tested on the Rolling Road at Marinello's in Egham near Staines where I lived at the time. Then changed all the suspension and brakes to the Vitesse types. Had to stop her somehow 😲 The Herald had piddly drums! I resprayed it ('hired gun' this time😉) from hideous pale lilac to metallic mid blue. Ended up swapping it for our Finance Director's Rover cos he wanted the souped up Herald for his girlfriend 😉 Then started respraying that; black and silver 😊 Sanding back my cutter I've just discovered another thin spot I can see light through 😡 Back to the resin and tissue stage. BTW: also seem to remember reading about the airscrew-masts some years ago. Don't think it was a general thing but 'they were there' and obsolete for current aircraft. it WAS an RAF boat after all😉 Happy Vincenting, remember looking for the photos last year. Cheers, Doug 😎

6 years ago by RNinMunich

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Spektrum, new, useless...

Doug, I may well take you up on that, mate. I would really like to get it going. Could you PM me your postal address? The Jeti I first saw was the 14 channel and that was £845 for the TX and £70 something for the RX. but I was only interested in the Tx. I wanted to frame it and put it on my wall! Czechs are SO clever and the women are stunning. The new 18 channel is about £1400, but they aren't anywhere near the dearest, even if they are the best. Haverlock, you can sing the Taranis praises all you like but anything that needs a PC to fiddle with it to get anywhere is the last thing I would pay good money for. I am a great deal more impressed by aesthetics in engineering, than complication. if I wanted to know what the batteries were doing I'd bring the boat in for a look. it would add some interest to what is essentially a rather tedious pursuit (which is why I have a preference, still theoretical, for sail). Believe me, I would never "get" the Taranis or anything like it, in a month of Sundays. I'm just not interested in all that techy stuff. Norman, I'd appreciate any input if you fancy digging around in yours. I wouldn't know what to look at. I didn't when it was soft valves and 90Volt Ever-Ready batteries and I don't now. I might have had Radio Control Models and Electronics Magazine from No 1, but none of it made the slightest sense and my Dad, (who paid for the subscription) never had the time to read it. I couldn't tell you the difference twixt a Super-regen and a superhet, a tone or a reed set. My old chum still has a working ED reed 8 channel set, but when flying, he has to constantly retune something with a plastic screwdriver, WHILST FLYING!!! And how did anyone ever do full aerobatics with single channel bang-bang escapement rudder onlies? Cheers, Martin

6 years ago by Westquay

Forum

Council madness...

Hi Guys, May I change the angle slightly? I use the lakes at Oxford, St Albans and other 'park' locations and I am heartily sick of having to put up with other users of the parks feeding the ducks etc from the jetties, platforms etc from which were clearly intended for model boat use. Result? Waterfowl poo everywhere I put the model, TX or tools. Perhaps if they had to feed the ducks by kneeling in duck poo, they would not do it....😆

6 years ago by wunwinglo

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Wherry hull in GRP

Even single masted and sailed vessels sail well without digging in at the bow.Lateen or triangular sail pattern. Carvel or clinker seems to make no odds. However I believe round bottomed hulls get pulled lower in the water when moving through it. That seemed to be the case with a Jetex boat I made as a lad. The outrigger booms at deck level dragged in the water under power. I chined the hull and it planed with the booms clear which seems to prove the point👍

6 years ago by onetenor

Forum

Scratch build twin pontoon water

Hi fellow mariners, winter approaches time to get a couple of projects under way. Is there a general rule for the positioning of the pontoons in order not to flip over at speed. I am using a nqd water jet for propulsion mounted in the centre hull. The pontoons will be hydroplane shaped with a step half the length of the lower surface. Aluminium tubes will run from one pod thru the main hull into the other pod. There will not be any panel shrouding between the pods and the main hull like a true hydroplane. Overall length about 30cm not sure of the width yet. Have seen a few foam builds on utube but really no help. Any help would be appreciated Gordon from downunder😆

6 years ago by Grumpy1949

Response

Command Boat 90

The Real Boat has jet drives, but unfortunately the little 20mm ones on the NDQ boat would not move a 52in version shown, there are larger jet dives for models available from Germany but it would cost a lot more than my budget would allow. I did try to make some but they were unsuccessful. I have seen them fitted to other smaller CB90's but the crash stop looks pathetic. and jet dives are not very efficient. I would love to take a trip on a real one! I've just found a plastic kit version by Tiger Here's a YouTube link to an unboxing:- https://www.youtube.com/watch?v=Fr5xGoMjBlI

6 years ago by CB90

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Command Boat 90

I tried one of these but couldn't get it to reverse the boat. Possibly not got the correct set up for the jet nozzle. it pushed a 30 inch fiber glass fast patrol boat very well, might try to sort outlet to give better control. You've raised my interest again thanks, Colin.

6 years ago by Colin H

Response

Command Boat 90

Hi I like the boat would be interesting with jet drive. they are available quite cheap for the nqd from £9.01on ebay item no. 282721477302 comes with cheap brushed motor can be converted to brushless to make things interesting hope this gives you food for thought for maybe future build. thinking of building a deans marine PBR cannedheat and fitting it with a couple of these jet drives.

6 years ago by BigAlio

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Pt boat

I guess it could be sealed up. The opening to the jet drives is small. You can't get your hands in! The opening which is under the 50 cal.on her stern. is meant more for working on the jet drives! To grease if you will! You could maybe spray some kind of sealer! But why have to fix a brand new boat! I was told I had gotten a leaky boat. As for her sitting low. It's just the design of the thing! As the jet drive pump water. the boat digs into the water! Don't get me wrong it's a great looking boat! I sent mine back, the wife wants me to get another one!

6 years ago by figtree7nts

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Pt boat

When you say leaks from the jet drive, is it not seal able yourself. I know you shouldn't need to being a new boat but is it just a bad seal that can be rectified with sealant ? I like the look of the boat it rides the water well at speed. But it does seem to sit very low in the water at slow speeds.

6 years ago by BOATSHED

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Pt boat

Very detailed boat, But they tend to leak from the Jet Drive! I had one had to send it back, Pity great looking boat! Do a bathtub test before you decide to keep it....

6 years ago by figtree7nts

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Denatured Alcohol

I wish someone would do Jetex again I loved them. Specially on little flat plate s I used to make with balsa sheet. Real skimmers they were .👍 Yes Doug I remember them and a bigger posher version that sat in the hearth or in the actual fireplace with a sack stuffed up the flue to stop heat losses up the chimney. A bowl fire I think they were called and I don't think they were pumped up

7 years ago by onetenor

Blog

Finally it's completed

Six months ago I drew up the plans for my Jet Sprint boat and at last it is completed and ready for its first test run Very happy with results so far so hope it performs well on the water Have leak and ballast tested it and all good so here's hoping for a successful first run up the river Has been a real challenge at times but well worth it and a lot of satisfaction and fun making it I have named it "Rapid Hoppa " so I hope you all like it Will post a video of its on the water performance as soon as I can

7 years ago by Rod

Response

Red Cat hydroplane

Hi. it is a scale model of a Formulaboats.com sponsord jet turbine powered hydroplane. I think this livery was from 2009. They can be seen racing on Youtube https://www.youtube.com/watch?v=A4HPB4PtT0k .As for the burning out motors that is sorted. Nothing to do with my cooling system but the unit I had from Hobby King seems to have a number of complaints about them burning out. So replaced it with a different model. HK have been very good and replaced all 3 failures. I will keep the latest replacement for another boat.

7 years ago by SimpleSailor

Forum

Seabreacher

Hi I have a 36 inch model of a seabreacher dolphin boat powered by a 50mm waterjet and a 800 brushed motor on an 11.5v lipo.I have not got it onto the water yet and just wondered if anybody with a jetboat could say if this setup is powerfull enough

7 years ago by Captain-Steve

Forum

Seabreacher

Hi Steve Plenty of suggestions being made. I use waterjets and you should be aware of the max revs quoted by the manufacturer. You exceed this figure at your own risk. I agree with the previous comments regarding brushless delivering far more power if powered by Lipo. Ballast is a crucial part of the equation and the Sea Breacher has a large volume of air in its hull which makes it very buoyant. Like a sub perhaps some form of ballast tank that can be vented may be worth considering. You really need to speak with someone who is into submersibles as they have the experience and knowledge of how best to proceed. The Model Boat Convention is on next weekend and they sometimes have submariner modellers in attendance. Good luck Dave

7 years ago by Dave M

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Jet Sprint Boat

Next week will do Rod😇 Cheers Wayne

7 years ago by Midlife306

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Jet Sprint Boat

Great; thank you Rod. I will look forward to seeing it. There is no rush! You are doing a great job don't rush it.

7 years ago by John2

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Jet Sprint Boat

Just thinking lol Got any ideas ? Would appreciate some input as a good design can make the finished product really good Cheers

7 years ago by Rod

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Jet Sprint Boat

Most definitely will have something just not quite sure yet probably have Kermit on it somewhere Will post as soon as the whole job is finished

7 years ago by Rod

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Jet Sprint Boat

Will definitely do a video but might be a we while yet

7 years ago by Rod

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Jet Sprint Boat

Ps. Rod, I love Kawasaki green colouring. Hopefully, there will be a contrasting bit of decoration somewhere on the craft 😎

7 years ago by rolfman2000

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Jet Sprint Boat

John, I think we are all waiting for that video matey 😀

7 years ago by rolfman2000

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Jet Sprint Boat

I think it is a great idea 😁

7 years ago by John2

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Jet Sprint Boat

Would love to see a video when you get on the water 😁

7 years ago by John2

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Jet Sprint Boat

By the time I fit the roll bars and seat together with 1/4 scale driver it will look a bit different Plenty of grunt as it develops 3.25 hp Cheers

7 years ago by Rod

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Jet Sprint Boat

Hehe, that engine looks real tiny...👍

7 years ago by Midlife306

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Jet Sprint Boat

Here are the rest of the photos

7 years ago by Rod

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Jet Sprint Boat

Hi Wayne Can't have that lol Fitted engine and currently wiring up all the controls Has taken a bit longer than I thought because of my other projects like finishing Sovereign of the Seas and preparing RC Beaver for flight oh and trying to get a bit of oil painting finished off Who says retirement is boring lol I just keep running out of time not enough hours in the day We have a national model boat show on over labour weekend in October so I hope to have the jet finished by then but have to do some R and M on the Corvette and Amara tug steam engines before then as well Have posted latest pictures Cheers

7 years ago by Rod

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Jet Sprint Boat

Come on Rod, I'm getting update withdrawal symptoms, pic attached to make you feel at home👍 Cheers Wayne

7 years ago by Midlife306

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Jet Sprint Boat

Hi Dave Yea we have the same rules down under with not being able to use petrol powered boats on local lakes but this one will be used on smallish river rapids so well away fro the locals Be a while yet before I get to test it Much to do to complete the model

7 years ago by Rod

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Jet Sprint Boat

Jet Sprint Boat

7 years ago by Rod

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Jet Sprint Boat

Great work it will fly on the water surface

7 years ago by saintsalvio

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Jet Sprint Boat

Mighty meaty! 👍 Good luck with the 'Messcave' 😉 I have the same problem 🤔 Pics show (amongst accumulated junk from various repair jobs!) - electrics bench and boxes of 'stuff' acquired over the last few years of my working life still waiting to be sorted out 😉 - various ships waiting to be refurbished or fitted out; HMS Hotspur 1:72 H class destroyer 1936, HMS Belfast 1:128 6" light cruiser U25 (or 26?) 1:72 Type IIA U-boat 1936 Billings Gina Danish fish cutter Graupner Southampton Various Plastic Magic projects (stash!) - the bigger ones; HMS Hood, Ark Royal, Illustrious, Type 45, USS Enterprise (The Big E), Bismarck all 1:350; USS Fletcher destroyer 1:144, are down in the cellar, the bench down there is just as bad 😡! and finally - my poor old Sea Scout being sanded on the kitchen worktop for lack of space on the bench! 😭 "Stuff accumulates to fill the space available for it" 😉 cheers Doug 😎 Oh! Nearly forgot 😲! and there's a 1:128 Graf Spee pocket battleship on a shelf in the living room, waiting for propshaft repairs.

7 years ago by RNinMunich

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Jet Sprint Boat

Wonders. Looks fab. And with that amount of power should move as well. Our lake prohibits petrol or nitro boats, so big brushless would be out preference with maybe a 2 x 6s Lipos in series giving 12s power. Best wishes Rod. Good luck cleaning the man cave. Cheers, Dave W 😊

7 years ago by rolfman2000

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Jet Sprint Boat

Perfect choice Rod👍 🐸

7 years ago by Midlife306

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Jet Sprint Boat

Great idea 👍 on the transom as well 😉😎

7 years ago by RNinMunich

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Jet Sprint Boat

I would put Kermit on her bow.

7 years ago by figtree7nts

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Jet Sprint Boat

Great Color! easily spotted on the water!

7 years ago by figtree7nts

Blog

Jet Sprint Boat

First coat of paint is applied Very pleased with result Kawasaki green so I can spot it on the water easier Think I will name it Kermit and paint him on it somewhere What do you think ?

7 years ago by Rod

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Jet Sprint Boat

Thanks Dave,will build up to speed in increments,as my mate says "the throttle works both ways"!

7 years ago by philpjuk

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Jet Sprint Boat

Hi Phil No problem I enjoy tasking opportunities to expand my knowledge. Weight distribution can be critical in marine craft and your solution should help control the lifting problem. With the mono you should not experience the problem, but with lots of power and a very aggressive jet of water I would expect the initial 1 to 2 secs to be interesting and you will need to be on your toes to keep it straight!

7 years ago by Dave M

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Jet Sprint Boat

Hi Dave,sorry the problem with sponson lift is with a prop driven strimmer powered boat,it is always the same sponson that lifts and this is due to prop torque.As it is a "pickle fork" type boat I am going to make it asymetric putting the hull nearer the lifting sponson and move the fuel tank and radio battery from behind the motor to the front.I asked the question to see if anyone thought I may have trouble with my ,(this is a mono hull).This is all my fault,I insist on fitting engines with far too much power into every thing!cars,motorbikes and boats,(I have bought a coventy climax fire pump to fit in my 11 foot sailing dinghy!).

7 years ago by philpjuk

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Jet Sprint Boat

Hi Phil I have no experience with three point hydro so any suggestions / observations are not based on personal experience. Is it always the same sponson that lifts? With three points of contact any slight misalignment or weight difference could result in one point digging in and raising the other. This would be made worse if the thrust nozzle was slightly misaligned. As Doug has pointed out the full size were difficult to keep in a straight line. You haven't said but I assume you correct the lift by turning the Nozzle. When I used to fly model planes I used to apply slight right rudder to keep the model straight on take-off and I wonder if you could apply a similar principle to your model. This is real cutting edge modelling and I look forward to hearing how you progress. Dave

7 years ago by Dave M

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Jet Sprint Boat

Thanks Dave,no the dinghy had no torque reaction on a steady throttle just when the engine was "blipped".I started with a butterfly flap in the nozzle which worked ok,replaced that with a steerable tube beyond the nozzle which also worked ok and finally with the nozzle itself steerable mounted on a flexible pipe which did not work (the flexible pipe was far from flexible when full of water at pressure!).The question was because I have built a three point hydro with a strimmer engine which becomes two point due to torque,lifting one sponson as the throttle is opened.

7 years ago by philpjuk