Thought Id start a Build log on this boat of mine, the hull and deck are a 1/10 scale factory moulding , so far I have made and fitted the drivelines and twin rudders and made some wooden decks. I have 2 airplane starters as power and 2, 14AH gell batteries. Today I did some tests and discovered that the motors draw 18 amps in the water, boat held still at 12 volts. They draw 40 amps at 24 volts but wisps of smoke from the motors, much more power but less runtime and longevity of motors compromised, Im going with 2 Electonize 30 amp controllers for now. I have a 12 kgf servo for the rudders. Have posted a couple of questions in other forums and here will try to keep all new questions here.
Regards Nick

Started on Stainless railings today, Bent up top rail out of 3.0 mm solid, posts are about 2-2.5 solid, second rail will be 1.0 mm mig welding wire threaded through holes halfway down the posts.
regards
Nick

Hi Nick,

Where did you source this hull and deck from?

Looks awesome, Nick!

Nick...looking good

Hi Kmot,
The hull and deck came from the factory that builds the boats, I just happen to work there occasionaly, they produce a 1/10 hull for promotional purposes and when they design a new boat.
www.kingfisher-cruisers.com/ to see the full size boats

Thanks for the praise smart_racer and forklift, Im hoping that logging the build will keep me motivated, ive aready been procrastinating on this for months.
Regards
Nick

Now to work on the rails again

Nice boats Nick. I especially like the rear deck photo on the 54' Flybridge.

Pulling 18 amps of current at 12 volts on those BIG 70 mm props is a lot of current. I would suggest gearing or belting them down, either a 1.5:1 or 2:1 reduction would help your motors and run times quite a bit. If your motors are running hot then you are wasting energy as heat, it should be used as propulsion. You are building a boat not a heater.

Worked a bit on the Railings today, soldered all the posts in to the main rail, and ran a smaller rail half way down the posts, will post pictures when its all polished. I use silver solder to weld stainless steel, I find it very quick and easy. it took me a couple of days to drilll 1/16 holes in 1/8 rod on an angle, ended up breaking 7 drill bits, making a jig to get the holes started then finishing off in a drill press (30 odd posts in the end.) and thats only around the bow, dry fited the rail and does it change the character of the boat, even the wife was impressed.

Question, what glue should I secure the posts with, they are fitted into holes in the hull. The rail is a tight, solid feel.

Green-boat, when I tested the motors I was holding the boat still, so worst case scenareo so to speak. I would think that normal running wouldn't have close to the amp draw, The motors were cool to touch after 5 minutes of running in this state, maybe I'm off the mark here but I chose these motors because they are much bigger than the standard hobby motors, the rpm of the motors is not reduced by a significant amount from un-loaded to loaded so I would have thought that the motors would be running close to the peak of their efficiency curve. They only spin at 3500 rpm so any sort of gear reduction will hurt the speed. If you or anyone else can point me in the right direction or sugest alternatives with regards to motors it would be apreciated.
I would like to see similar performance as u163665 "s Donzi

PS most boats this size would probably be running whipper snipper or equivelent power rather than electric, only my club wont allow it due to council regulations at the lake we sail at.

Average whipper snipper's are about 2 HP, which converts to 1500 watts roughly. At 12 volts it would mean to get equivilent power each of my 2 motors would have to draw 60 amps. I dont think Im doing too badly at the moment. Sea trials in a couple of weeks I hope should give me some firm data to mull over at any rate.

regards
Nick

Your current draw will go down some when the boat gets moving. I was just concernd about the "whisps of smoke" coming from the motors that you described. If after running the boat at 12 volts for 5 minutes and the motors were still cool to the touch then you should be ok.

Originally Posted by green-boat

Your current draw will go down some when the boat gets moving. I was just concernd about the "whisps of smoke" coming from the motors that you described. If after running the boat at 12 volts for 5 minutes and the motors were still cool to the touch then you should be ok.

Thanks for your concern, the smoke was when I was trying them at 24 volts and 40 amps, 4 times the power but the motors (and speed control) wont last at that current.

Still it was cool to see the wash from the prop disurbing the water 15 feet back from the boat. I think the smoke was coming from the brush holders, they are only molded plastic. calculating it out at 12 volts the power output is 216 watts and 24 volts is 960 watts for those that may be interested.
Regards
Nick

Received my speed controls today at the club sail day. This afternoon I fitted all the Deans plugs and installed the controls into the boat, I have a JR 66Max 6 channel radio, so I set up the motors so they both operate off the left stick, throttle forward, both motors spin fwd, reverse well obvious i guess. If I have no throttle but push stick to left motors turn to spin boat left, right stick opposite. If i have partial to full throttle and move stick left or right inboard motor slows down to stop and may even slightly reverse if only part throttle on. I'm going to use the right stick for the rudders and updown for an anchor winch.
My two batteries are wired in parallel to two 15 amp resetable circuit breakers that individualy supply each speed control.
It was sugested to me to run each battery as a complete independant system in case one motor or control fails, any thoughts on wether to link or leave batteries independant?
Just waiting on a servo extention now so I can get the rudder sevo working. Regards,
Nick

Well I took the boat down to the water today for a sea trial, and everything was fine. I started off steadyly just to get used to its handling all was good. I could turn the boat in a circle I couls steer the boat on the rudders, revese was good, I then started to get adventurous and increase the throttle, all good but it ran a little bow down, moving the batteries back a bit fixed that. The speed was dissapointing, it did look scale as if the full size boat was at 3/4 throttle, on the plane but inefficently if you know what I mean.
So anyway I ran for about 20 minites mucking around. I thought I would see the response from reverse to forward and out poped one of the couplings, brought the boat back to the wharf and the motor with the popped coupler wasnt working (im sure I heard it running unloaded when it first happened), Oh No ive blown a nice shiny new speed controller. swapped over some connectors to isolate it and dicovered the controller was ok its the motor that has blown. Both motors were warm, maybe 40 deg C but definitly less than 60, the controllers were cool. I have 15 amp resetable breakers in the circuit so even though the motors pull 18 amp in a static thrust test they must pull less than 15 even acccelerating.

So anybody got any ideas, I want 6000 rpm at the prop, preferably 8000 rpm keep the max current below 30 amps at 24 volt or 12 volt.

Pulled apart the damaged motor, The brush holder had melted so brushes were locked in place, I will look into making better holders out of circuit board material and brass brush holders from old wiper motors.
Added photos of the engine room, damaged motor and bow rails.
regards
Nick

I made 2 new brush holders out of the materials I mentioned, here is a photo. nothing but a dremel used, first one fitted to motor, working well, even able to put a suppresion cap on them now, how nessesary are the caps to the case? Ive left them out due to nowhere to attach them to.
Wow, the macro funtion on the camera realy shows up every thing