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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

Forum

My other hobby

I've gotten a chance to fly a few times. And loved every time! But it's been on big jumbo jets! Never had the opportunity to fly on a small aircraft! Now that sounds like great fun...….

5 years ago by figtree7nts

Forum

Transfers

Hmmmm!! Waterproof? Have you ever tested that? I'm not so sure, having used them in the office virtually since their inception. Anyway, when they are mounted on the boat / ship they need sealing in with a coat of clear lacquer or they may sometime 'float' off again. Apart from that have not yet seen any transfer paper made for Laser printers. Transfer paper made for ink jet printers may melt 😲 in laser printers in the final transfer / fixing unit. I can tell you, it makes an 'orrible sticky mess wot ain't easy to get rid of. Doug

6 years ago by RNinMunich

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 Steve The Graupner Speed 900BB Torque specs are 6-40 volts, 6,500 rpm, 54A amps, shaft 6mm, dia. 51.5 mm, length 95mm and weight 645 grams. A brushless motor like the Hobbyking L5055 600kv is 11.1- 22.5 volts(3S -6S) power 1500watts, 55 Amps, shaft 6mm, dia. 50mm, length 55mm and weight 311 grams. On 3S=6660 rpm, 4S=8880 rpm and 6S=13500 rpm. The brushless motors are far more powerful and with an ESC with handles up to 6S(22.5 volts) you would have rpm's to drive a water . Canabus

7 years ago by canabus

Forum

Seabreacher

I think I would be tempted to go brushless with it. Far more power for the size of motor. I don't think an 800 brushed motor would have the revs to push much water through a 50mm . Even an 850 motor would be an improvement. But going brushless, you could get far more revs out of it. Best of luck with your endeavours, Dave W 😀

7 years ago by rolfman2000

Forum

RAF rttl D2763

A brief history After the second world war and as part of the occupational forces the Second tactical air force the RAF took over Sylt airport in 1945 and later in 1946 the RAF decided to use the airport and the airspace west of Sylt and Amrum as a firing range, and was known as RAF Sylt Armament Practice Station. From February 1948 to February 1949 the airfield was closed and prepared for the operation of jet aircraft. For target practice a target towing Squadron was stationed continuously on the station. The aircraft used were Miles M. 25 Martinet, hawker Tempest TT, DE Havilland mosquito TT. 35, Gloster Meteor F. 8, Meteor T 7. For instruction and training flights the flight also had some DE Havilland vampire T. 9s, hawker Hunter F. 4s, Hunter T. 7s. The aircraft of the target towing squadron were housed in the hangar of 402 near the South West of the Station. Therefore, the unofficial designation of weapon training squadron 402 was used at the time. For patrolling and securing the range area, as well as for rescue and training operations Marine Craft Section boats were stationed at List and Hörnum, Bristol Sycamore HR 14 rescue helicopters were Also station at RAF Sylt. Air traffic control boats and HSLs were stationed in the port of List at the beginning of the fifties (see pictures) D Boats In 1954, the decision was taken to replace the air traffic control boats and the HSLs with RttLs mk2s Rescue Target Towing Launch. As part of the rebuilding program to help the German economy the boats were designed and built by Krogerwerft Yard at Rendsburg. (Later taken over by Lursson ship builders) and were numbered D2762- D2766 these boats came in service mid 1955 which explains why my Father severed on both HSL and D-boats (preferring the D-boat) D2762 and D2765 Based Hörnum, D2763 and D2764 from List, with D2766 as a reserve boat in the event of maintenance or breakdown, Their design was very different to any other boats in the Marine Craft Section/unit more like the German Schenllboot or S Boot (allied code name 'E' Boat which my father always used), with flared bows and rounded bilges and powered by high speed diesels. The D boats were fitted with winches for Target Towing, these were removed as the boats duties were change to Range Safety and ASR These boats only served with the RAF, until 1961. Two were sold to the south African Air force D2762 and D2764 in1961, and the other three handed over to the Federal German Navy in 1961. All were subsequently used as ASR craft. D- Boats in German service The German Navy, the “Bundesmarine commissioned them on 1.9.1961 as FL 9 to FL11 and were used by Marinefliegergeschwader 5"naval aviation Squadron 5” Until end of September 1975. the three were termed as air traffic control The fate of these three boats is a bit uncertain, one of these boats was in the process of being sold as NVG S1 as a North Sea supply boat, this deal fell through and the boat was sold to private owner in italy (no further record for this boat found) the other two boats are said to been scraped or de-commissioned , however these boats are quit properly the two that ended up in the service of the Spanish customs service as cutters, after they were confiscated when smuggling, I have tried to contact the Spanish about these boats but have not heard from them and presume they were scraped or sold in to private hands ( there is the suggestion that they were driven on rocks and sunk, no evidence found) D-boats of the South African air force/navy The two boats that were obtained by the south African air force in 1961 were originally known as R30 and R31 and they served under SAAF until 1969 when the unit was taken over by the south African navy and R30 became P1552 and R31 became P1551 these were changed again when holiday makers referred to the boats as PISS1 and PISS1 too R30 to P30 and R31 to P31. Both these boats were diffidently sunk R30 Lost off Saldanah Bay on 7 October 1988 after striking a reef off Danger Point. R31, near Cape Point, after she grounded through contaminated fuel issues There are somethings about these boats that strike me as odd, The originations that took over these boats, they don’t like to mention the fact that these were ex-RAF or British boats, There is no record of the Spanish boats, it is said that they were sunk but no details are available except what is said on one form. I think I have done as much looking for information as I can, most of the bare facts are stated so thanks to all those web sites and forms that I have used and the pictures I have used I would like to thank to Dave M for the drawing And thanks to the marine craft branch museum for their help and for putting me in touch with Mr Rick Mortby who built the museums model of the D boat And a big thank you to Rick Mortby for the scale drawing and for his trust. And to Dr Christian Ostersehlte historian for Lurssen shipbuilders for the pictures of my Fathers boat D2763 and now I can start the building of the model D boat

7 years ago by teejay

Response

Jet Sprint Boat

Hi You can source the s from Gravitix I am looking at the 50 mm unit Watch the progress on the hull and if you still want one just let me know Can't give you a price at this stage as development Costs are ongoing at the moment Nice to hear from you Cheers

7 years ago by Rod

Blog

Jet Sprint Boat

Have been trying to source a 1/4 scale hull for a jet sprint boat but not successful so decided to make my own Borrowed a small model identical to the one I wanted and set to scaling it up by 2.5 times I have shown the start of the journey and will continue to post development until it is in action Have sourced 1/4 scale driver and navigator together with and electric water cooled motor which will need to produce 3 to 4 hp to drive the shaft Hope you all like it because it's been really interesting so far I should be in a position to pour the mould shortly and then have a fibreglass hull taken off😆

7 years ago by Rod

Response

Sea Breacher

Hi Hugh I do believe Brian used the Graupner water which had it.s own seals. The model was sold on some time ago so can't check. I will ask Brian when I next see him and update the post. As far as I remember water ingress was not a particular problem. Dave

7 years ago by Dave M

Forum

ESC problem

Hi there, bit of a newbie to ESC's Need some advice on what AMP rating to get for the current setup any and all help is appreciated. Prop -> Graupner Jet Propulsion Unit 5 (2347) (G2347) Flange Diameter: 78mm Shaft Diameter 7mm Motor -> Graupner HPD 2948-3760 7.4V Brushless Motor Operating voltage range : 7,4... 24 V All-up weight, approx. : 180 g Free shaft length: 10 mm Output : 2000 W Number of poles: 4 Permissible motor direction : R und L Case length: 58,2 mm Shaft diameter: 4 mm Max. charging rate: 105 A Case diameter: 29 mm Revolutions/Volt: 3760 Part No: G7757 Battery ------- 7.4v 2s 40c 5600mah Boat -> Weight: will be 8 Kilos once equipment fitted. currently around 5 kilos. length:1.3m I hope that this information is suitable and can help with my question. many thanks 😀 Ashley

8 years ago by sheaffy

Forum

ESC problem

Hi Ashley Welcome to the site. With such high currents it would be advisable to fit a fuse in the wiring to the battery. I would reiterate Haverlock's advice, LiPos need correct handling in both the charge and discharge. The lowest recommended charge (should be with the paperwork received with the battery) for your battery should be observed and should be set in your ESC. Don't store them charged, the safe voltage is 3.7volts per cell and most decent chargers have a facility to discharge to this voltage. A Wattmeter would be useful the check the actual current under load. Exceeding the motor or battery rating will cause damage and for about £20 a Wattmeter will save you time and money. The Graupner Jet Drive is interesting to me as I am awaiting two jet propulsion units from KMB for my Shannon lifeboat. There is a max rev limit of 20000 revs on these units so it is important to match the brushless revs or risk damaging the bearings. I can't find specs for the Graupner but I suggest you check your documentation. Good luck and please keep us posted. Dave

8 years ago by Dave M

Forum

700 to brushles direct replacement

Have an old Billings jet boat that goes (ok) but needs at least 14v. Finding speed controllers is a struggle. SO, does anyone know of a brushless motor that could be a direct mount in the . Thanks Derek.

8 years ago by Derek

Forum

Old speed controller

HI Dave I acquired a Billings Palm Beach jet boat from around the late 90's with a 9.6v 700BB turbo. Was on 8.4v, I put 12v in, much better. I was told that this jet & motor unit runs well on 14.4v. So as its a mans thing for MORE POWER, I fancied trying it. I do have a brand new spare motor laid around if needed. I'll just bide my time until I stumble across one. G oing to give a 3 cell Lipo a go to see what happens (less weight). Just need it to stop raining on club sailing days 😀

8 years ago by Derek

Forum

Billings Palm Beach jet boat

I've acquired a Palm Beach jet boat, mainly as I didn't have any experience of this type of propulsion, so thought I'd give one a try. It's obviously old as the battery is nI cad dated 1999. Has anyone any info on these things, i.e. make of , can the "prop" be assessed etc. Told it's got a 700BB turbo, this seems to be standard fit going by a web search. Any idea of Max volts, it came with an 8.4v cell. Thanks. Oh, and Happy new year.

8 years ago by Derek

Forum

Billings Palm Beach jet boat

HI Derek I think you will have a KMB in there so to remove the prop take off 4 screws that hold the nozzle on remove motor and coupling and push out the whole shaft it is a snug fit, the shaft runs on a roller bearing you might want to check the condtion of that , the 700bb will run on 14.4 v with no problem , I have a pair of them in my 49 inch Perkasa running on that voltage with out issue for more years than I care to remember hope this helps for more info on your check out http://www.kehrer-modellbau.de/en/ and Happy New Year to all 😀

8 years ago by AndyK

Forum

Jetex

: Boaty Great idea that, using a pulse jet. I understood that in the past this has been tried on tethered hydroplanes and certainly it would be cheaper than gas turbine units. Nearest large area of water to myself, apart from the River Mersey is Bala Lake in North Wales but I dont know how the locals would react. Only person I knew who sailed a model boat on Bala was in the late 1980s and the boat was a scale model tug. Fastest model I ever had was a J.B Marine Hypercat in 1994/95. This was powered by a water cooled Graupner 700 brushed motor running on 2 X 8.4 volt nicads with top speed being 35 to 40 m.p.h. However, the boat met its end on Walton Hall Park lake in Liverpool when some debris fouled the rudder and it crashed into the concrete bank , took off and nosedived onto the footpath. It did have a nice rooster tail and thrilled many spectators. I have been contemplating getting another fast electric and wonder if a water is available to give equal performance. Boaty

9 years ago by boaty

Forum

fast electrics

To match your IC performance Brushless is definitely the best option. At 40" your model is not that big so weight is possibly a major consideration, so NiMh or LiPo should be the power of choice. if you are new to LiPo do follow the instructions and use a proper balanced charger. Looking at hydroplanes on Google suggests they use jet propulsion, so are you considering some form of ducted fan? We have members in my club who use ducted fans on skimmer type models and with some careful setting up they look very Impressive and really skoot along. As model flyer you possibly have some knowledge of ducted fans and I have seen them advertised with suitable motors. I used to fly model planes but never had experience of ducted fans, but I guess you can get thrust details and marry this to your model. Giant Shark have a section on EDF units http://www.giantshark.co.uk/sector/94/edf so this may give you some help. Do you have plans/pics of your model? You may get more help if members know exactly the sort of Hydroplane you are building. 😀

10 years ago by Dave M

Forum

Producing Controlled Vectored Thrust In any Direction

HI David Dynamic positioning is fairly advanced technology for a model boat. Do you have a particular model / purpose in mind? The VP system seems to be much favoured for use in tugs / ferries in the real world, as your research has found, where small spaces and instant changes of thrust are necessary. On a model the real problem is the draught required by the blades. Many of the more recent large passenger/cruise vessels use multiple Kortz nozzles both fore and aft and I assume they can achieve good control as well as providing economic thrust for use at sea, or they would not be so popular. Water jets sound interesting but I suspect the technology would be complex to produce reliable jets. A fellow modeller used a water jet on his model and found that he had to strip the unit right down after each sail as the bearings and shaft were seized. Electronics are already available to control and mix two propellers to control speed and direction so if you can find or design 360deg rotating Kortz nozzles the solution may be in sight. Apart from the cost I believe Graupner may be up for sale so supplies may not be easy to come across. I'm all for british brains and innovation 😀

11 years ago by Dave M

Forum

Graupner Moonraker for sale

Luxury motor yacht. Partially constructed. Jet propulsion units partially Installed. Kit complete plus fittings with everything needed to complete the model. £800 Also Navy F14, unused bought for the Moonraker, extras Include linear proportional channel mode,short aerial and battery pack. £230

11 years ago by terryaki

Forum

RC Floating Musical Fountain

Well It's nothing you've ever seen on a pond before! Something I've been working on for some time... Partly because I'm mad and partly because everyone likes water displays right? 😀 It plays various different tunes, still some tweaks required before I actually do put It on the water. It runs on 24v although the motors are on 12v. It has 16 water jets with blue and green lights built In on each one that are all Individually programmable. 8 red outer LED's and another 16 colour changing LED's on the under side of the lid. Also 3 strips of electroluminescent wires not shown operating In this video, two colours around the very edge of the lid and another underneath. 8 flash bulbs which are actually LED halogen equivalents. These are programmable In sets of 2 and two marine speakers for the sound. Inside we have the programming unit shown on the left, the pump, two accumulator tanks and a pressure regulator. Also the speed controllers for the motors and a custom built control board and small control box. The radio control receiver also operates a servo hooked up to a volume control pot and the controller so I can operate everything from the side. There are 3 batteries In total but surprisingly It doesn't draw much power. So why am I posting It here? Because It's my website!... and I'd like to peoples response to It really. It's a unique project that's kept me busy for the purpose of pure entertainment and an electronics challenge 😎 Post your comments below! Does this project take radio control boats a step too far Into the realms of technology advancements? 😛 Stephen

13 years ago by fireboat

Forum

maybe not

Paul red181 and I have been playing trying to go faster with his Huntsman and fire boat we have used a GPS and found that useful with props because noise makes you think it is faster, amp volt I bought the jetI system and tried it on a small twin brushed fire boat, you can see amps volts rec voltage and rpm temp and now Fitting but I have not bought that unit yet , the read out I have gripping on top of the tx but it is very difficult to read and change display pages when running, so we both bought eagle tree systems that have the advantage of storing the info and you can down load it to a pc and do overlays just like F1 cars do. so although the jetI system is good on first runs ( especially as Paul is running a expensive castle creations speed controller and binned one) we are careful to do short runs and check temp when testing now. I also have a custom built one by a mate that does simmilar to the eagle tree that I have not tried yet .we have been using bits of each to get the best results the jetI is ok but you really need someone along side holding it and scrolling through the pages and telling you what info you want, you can also set alarms for temp volt it automatically tells you about going out of range and receiver voltage, the eagle tree is great as you have a hard copy to hold and keep and compare we are just changing motors again so all the date can be used to compare to give an idea where to start and the first run will tell us if we where right and what direction to go we also have two twin brushless fireboats with highly modded motor mounts but not geared like we have used in the past. Ill find some pictures of the tx and post them peter

13 years ago by Peter HS93

Forum

Hitec Live View Full Telemetry Package

I have a JetI system that does the same, had it 12 months it's in a FF9 tx it will give you all the things the Hiteck will but not direct to laptop, I have a small gps unit that plugs in to a laptop to download all the tracks to google earth and plots on a map the path and speed, we have been using this for over 12 months, what you may find is you need 2 people to use this equipment on a fast boat, but if its a plodder you will prob have time to look at the screen the laptop and your boat.I think this sort of equipment is great and would be even more useful in the likes of a steam boat if it could give feed back from the engine and boiler peter

14 years ago by Peter HS93