Martin you do have a way with words, I like it!, yes, and steam locomotives run on at least ten times the pressure of a steam driven boat. Happy memory's of the old New Brighton lake, my nan and mum would take me over from Liverpool on the ferry, which in those days went to New Brighton, with my pride and joy under my arm, my "victory models fire boat" remember the one? all plastic with twin brass screws driven by a mighty midget motor. The old lake was demolished approx' 10 to 15 years ago and the new one constructed 30 yards further up. I was there as demolition was going on and the old lake was a large heap of concrete and rubble fenced off to the public. Do you know to this day I so so regret not squeezing through the fence and taking a hand size piece of the concrete side wall, the concrete wall I would have lent over 1000 times as a young boy of seven to launch my boats.
[Score: 5/10] 39" MTB379 Capable of 14mph Twin Propellors (3 Blade 45mm) Direct Drive Powered by LiPoly (7.4v) Batteries - Comments: This model was originally built by my father in the 50's for i.c. power. It was laid up in 1962 and remained inactive until two years ago. At that point, I egan recommissioning it, fitting twin brushless motors in place of the deafening single glow motor and straight-cut gears. I also added a great deal detail that my dad had never added. It performs very well nicely in this guise with the added drama of a throttle-linked digital sound system.
Skinned the frames added deck and splash rail also started on cabin and superstructure, added rudder and installed twin brushed Graupner 600 motors via Graupner style direct couplings. Motor mounting system through a bulkhead gives extra support to motors which mount on to end of the shafts. currently adding a rudder servo mount, as rudder is a close copy of the real boat's and still functional.
Just to clarify. Shipping was only 7 days to Canada, manufacture slightly longer. Examined the hull closely and was pleased. It is dimensionally accurate and robust, but light. It had also been reinforced in strategic areas and trimmed to the correct deck line. My many questions to Christian Sheppard – Capurro of MTBHulls were quickly and knowledgeably answered. A company I would recommend others. Reviewing the build blogs and U Tube videos of the both the Brave and Perkasa models, shows most use either single or twin screws. The original vessel had a triple screw contra - rotating layout. Experience from others suggests the third screw just adds weight and complexity, but little to the performance. Nevertheless, it was how the Braves were built, so that was how it would be. Christian gave several suggestions for other modelers who have built this vessel. Contacted them and was readily provided with information and advice. The finished weight of this model is important and a target of around 6 lbs recommended for a 1:32 scale version. This is to achieve the potential performance. Plans for drivetrain are 3 x 2835 4500kVa brushless motors, direct driving 3 x scale 3 blade 30mm screws. Decided use a single Li-Po battery for the best performance with minimum weight. It was suggested three batteries, each powering a single motor would be the best layout. After some research, concluded this would introduce a weight penalty and was discounted. There are various ideas for the best drivetrain. Unfortunately none for triple screws. Decided the best approach would be to fit the bare hull out as planned, then try it. Leaving all the finishing features for later. A contact in Australia had already done this using a single screw layout and kindly sent pictures of his hull layout and then under test. Very informative. The positions of the rudders, propellers and shafts are established by the scale dimensions and were permanently installed. Everything else was to be temporarily fitted, so it could be moved or replaced if necessary.
[Score: 8/10] 24"/2000g Interceptor Capable of 15mph and a runtime of 10mins Single Propellor (2 Blade X Type 35mm) Direct Drive to a 2958 watercooled (2 Blade X Type) Powered by LiPoly (11.1v) 6Amp/h Batteries Controlled Through Unknown 200A (100Amps) ESC - Comments: Zoom 1 (Interceptor) Mono boat. Built from a Glassfibre hull, brought on Ebay for £35 the hull is a slim mono racing type with a self-righting side cabin it runs a 1400W 14V 2958 4200KV Brushless Motor and 29-S Water Cooling Jacket with additional air cooling fan. I did not want to use a flexi drive as high maintenance and prone to failure so the shaft runs via two universal joint one at each end. the propeller is a 38mm copper alloy The ESC is a 200A and water cooled the twin rudders supply separate water one for the motor and one for the ESC. The rudder are positioned to reduce prop-walk and are hinged to prevent damage if hit a object in the water and ride adjustment. Turn fins and trim tabs for ride adjustment were provided by a spares kit for another boat. also foamed and added an inner sealed hatch, a rubber bump strip and safety loop. The Boat is fast and over-powered used at half throttle, may use a 7.4v lipo instead, the self righting works well. 20th April 2018 while running on 11.1v the boat stopped, no response on retrieval It was found that the manufacturers battery connector had melted and the connection lost see later pictures. the battery was made by FLOUREON and was a 35C with 5500mah capacity the 80A fuse had not blown.
Hi Mate, there was an offer on ebay £5 each for 2200mah 3s lipo's, so i took the plunge, bought 8 of the beasts, 2x2 in my Fireboat, with twin 700BB motors, thinking of swapping to brushless but SWIMBO has ideas for the garden!!!! Mark
I dont uses mixes, but do use exponential and rates (spektrum dx6i) with my twin screw brushless 4 foot fireboat. When at speed rates on, then it turns nicer, no roll, when going slow rates off so turns are sharper, if that makes sense. Mixing the throttles.. interesting not thought of that, but it will lose power/speed. We use mixing on planes for taxiing, particularly on water, but once airborne its off. My avatar has this as the cheapo motors just wont balance so it compensates for this on the water. With the boat its easier to control with rudder input. I like the thinking though!😁
Hi John, you might now be scratching your head, and wishing you have not asked the original question! This seems to be a common issue, as the boating community is light years behind the other disciplines, rc cars, planes helis and so on, its probably due to the facts general boating doesnt really need the later generation technology, the average boater age is probably higher than the other disciplines so budgeting might be an issue, and there is less younger blood in the clubs to explain the lipo/brushless etc. We see posts with a load of numbers, specs, warnings etc, its enough to put people off. Im a big fan of brushless/lipo/ 2.4 etc, been doing it for years, its cheaper and more efficient (once you have the basics) but for the average guy, who just wants to spend an easy afternoon at the local lake gently cruising around, brushed motors, nimhs batteries, even lead acid, will do the job👍 Your 4 foot ply boat, once painted, with fittings, will be heavy, I know, I own one. Those 600 motors are not big enough, they are better suited to the smaller 3 foot boat, then, pushing them with a 6v lead acid, just cant do it. The battery will be screaming HELP!! I started 15 years back exactly the same, 600 motor, 6v battery, massive 50mm prop, I knew no better and took advise from people who didnt know what they were talking about😡, remember those gold hi tech speed controllers!! I had one, it melted, literally melted on the first use😭 Get 700 size motors, they will need to be water cooled, as mentioned by jarvo, the nominal voltage or below isnt good enough, power them at the max voltage. Brushed means you can use one apropriate esc, look out for electronize (are they still in existance?) or mtroniks, preferably use nimhs batteries over lead acid with a high mah. If after all this you want to venture into lipos and brushless motors, go to a club, spot a boat that is similar in size to yours, if you like the performance talk to the owner and gain experience and knowledge that way, it will save money, lost time and a lot of disappointment, I have been there so feel your pain. I say I would never go back to brushed motors and none lipo batteries, but I always want silly speed, not runtime, after 15 minutes Ive had enough and am bored. Rambling over! My 4 foot boat is twin brushless and uses 4 lipo 5000mah cells per motor, it will do 25mph for 15 mins, then I go home😁 Message is, you can get a "reasonable" performance from brushed motors, with the correct batteries, right props, but weight is the enemy. Looks lie you are at Biddulph, get onto Dave M a moderator on here, and arrange to go over to see the crewe and district boys on one of their sailing days, take your boat with you, they will help👍
Peter, Had a look at the Raboesch site, the prop i looked at was the Metric 162 - 17, 40mm dia. As you are looking at a 42mm motor, this should give more than enough grunt. What make of motor are you looking at??? my 46" Crash Tender has twin motors, with 45mm dia props, the motors are from Airtec, a Yorkshire model shop, might be worth a look at their site Mark
Hi Jarvo I also have a 46" Fire boat, but, it's only single shaft as I am the second owner. I am using a L5055-700kv, 4S 5800mah 40C Lipo, 60Amp esc and a 2 blade 52mm prop. In a twin setup a pair of Hobbyking 3639-1100kv on 3S or 4S batteries with 60Amp ESC's and 3 blade 37mm props and if you wish more speed a straight change over to the sister motors the 3648-1450kv but you may have to drop the props back to 2 blade 40mm. Canabus
Hi Mate and welcome to the forum, (mad as hatters!!!) I have built the 46" and before you get to far in you need to decide if your having single or twin motors, and rudders, that way you dont fall foul of bulkheads, and shaft mountings, mine has Graupner 700bb motors on 3s lipos, but i am up-grading them to brushless soon, have the new ESC,s and the motors are on order. Great model to build and sail, attracts a lot of attention. Mark
Props by ChrisG Chief Petty Officer Posted: 5 months ago
Hello Doug Thanks for all of the useful information and yes it is a 'Black Art' and I have been party to some heated debates regarding props on large passenger carrying boats. I was highly amused by the link to 'Raboesh' which if it wasn't a Chinese company should have been. The model I am building is a Rother class lifeboat which will have twin props and a single rudder and I have read that due to the limited swing of the rudder the turning circle of the boat is much improved by having independently powered motors. Not at that stage yet still early days of the build. Thanks again and best regards Chris G
Built one of these a few years ago. Great for tug towing and rescue work. Had an Action mixer at one time and with two separate 6v batteries worked great. I could literally spin in the spot. Moved to twin motor control as I used to fly model planes and was used to using all four stick axis. Not sure a bow thruster will work well on this model as it is so manouverable. Makes into a nice realistic model and I wish I had kept mine. If I were to make another I would make a better seal of the rear deck, it leaks like mad in it's designed fit. I eventually made a raised coaming round the opening. Coming along nicely.