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[Childs]

Hi all

This is my ASRL as mentioned in my introduction, the only boat i have running at present. As you can see I have stripped her down just to do a quick tidy up during the winter months in time for the boat show in October then I will be attempting to do a full restoration on her (as long as I can get another of my boats up and running). I am looking to replace the motors and electronics for two reasons  1) my son was given a PT to use just needed a tidy up slight hole but no electrics and  2) The ASRL is running on 7.2 volts Nicd and at present I only get about 5 to 10 mins run time out of her, If i run her at top speed for to long i get even less than that so was thinking about ordering low drain motors and electronics from Electronize (as some members of our club say this is a good place to shop) and run her on 6v gel cell battery am I heading in the right direction........ would really appreciate your comments

[Childs]

Forgot to point out this was how I bought her.

[boatmadman]

Hern,

I have used electronize - good stuff. I have also used Action - advertised in the traders directory (with a mayhem discount), in my humble opinion, better stuff and great service. FLJ, the Action man will help and advise. As an example, he designed, built and delivered an esc for twin motors on a springer for me in 3 days.

If you wish , I will bring the goods over for you, ........if you pay the airfare

Ian

[Childs]

Thanks for the offer Ian only one condition you fill your suitecases with model boats as they can be very hard to come by here ..............

[Childs]

As I dont know very much about motors etc yet would i loose a lot of speed using low drain motors

[boatmadman]

Not necessarily, it depends on a number of things as well as the motor. If you use 12v batteries it will help, but you will need to upgrade the esc to cope with the current. The size and type of prop will also influence the speed.

If my understanding is right, and it prob isnt, a low drain motor will have multiple poles in the windings, resulting in greater torque and lower current pull. The benefit of greater torque being that the motor will sustain its max speed under greater load than a similar sized motor with fewer poles.

Ian (standing by to be shot down in flames )

[FullLeatherJacket]

Hern
I reckon that model is about three feet long - am I close? In that case I'd recommend two Graupner Speed 600 ECO motors running on 8.4v/9.6v 3700 or 4300 mAh Sub-C sized NiMH packs (one for each motor). Robbe two-blade 40mm plastic props is a place to start, too, but you might be better off with 3-bladers in the long run. Avoid gel cells in this application; they are just too heavy for a planing boat, and you can't fast-charge them at the lakeside.

One final thought - have you discharged and recharged the NiCAD pack a few times? They can get lazy over time and refuse to supply their full capacity if you just top them up now and again. There's oodles of stuff out there on the web about charging NiCADs. It's now generally accepted that NiMH packs have a much better capacity/weight ratio; can still be fast-charged and don't have this so-called 'memory'.

As Ian says, I can provide details of suitable speed controllers from our range if necessary. PM me your regular E-Mail address and I'll send you some PDF data-sheets.

FLJ

[John W E]

Hern Hi there

Looking at photographs of your model, we know exactly which one it is now.   It is obviously plank on frame construction.

Also, I notice you have 2-blade racing props on her.  This to me indicates that the last owner was trying to increase her speed - via increasing prop size rather than motors; now, the actual model itself will be in the region of 33 1/2 inches long x about 8 or 9 inches beam I think.   The actual hull is not a true 'planing' hull due to the fact that she has a very deep skeg/keel on the bottom.

This hull, although in real life was an extremely good sea boat;  there were several engine variants in them to try and increase the speed.  Max achieved was a little over 25 knots.  Some 650 hp.

So, basically, what I am trying to say is - do not expect this model to achieve marvelous speeds - as already has been stated if you use gel cell batteries, you increase the weight of the actual model.  T

Also, I am sorry to say, the duration with high speed motors/high amp motors is not very long in time.

I have a similar model - The Vosper - Air Sea Rescue Launch - with twin MTronik 500s in driving two three blade 30 mm brass props.   The power comes from 2 x 6 volt 4amp gel cell batteries and I am lucky if I can get 15 minutes on the water with it.

My personal advice to you would be to go the Ni Cad pack way; for power supply.   Try going to 9 volts Ni Cad packs - with larger amps.

Just as a side note; the particular launch model you have; I do not at this time recognise the number.   However, if you do some research, on HSL2507, this particular craft took part in a rescue which appears to be an epic for any World War 2 marine craft and its crew.  It was fitted with extra long-range fuel tanks (which your model has) i.e. the fuel barrels on the back.  She was stationed in the Shetland Islands during World War 2 and she was called out to survivors from a Canadian Catalina Flying Boat; who were in a rubber dinghy at position 65 degrees  OO.N  OO degrees OO.W

She achieved the rescue of these pilots giving her the unique claim to have rescued people from the furthest northerly point - the whole round trip took in 350 mile and took 36 hours.   

So, there is something to read - pretty famous boats.

aye
john e
bluebird

[Childs]

Guys thanks for the responses.
It has given me something to look at, At full speed the boat does plane very well at least a good third is out of the water, it is nice having the speed but seeing as our club pond is not that big having a longer sailing time would be a preference for me. i will pm you FLJ with my contact details as I would very much like to put a new setup in her ( especially as I have promised my son the old gear for his PT)  even down to changing the props to something more realistic.
Thanks for your info Bluebird have more incentive now to eventually restore her to her formal glory, looks like she may have swapped owners a few times each doing there own little changes.
With regard to the Nicds after each sail I connect a 12v headlight bulb to the battery and completely run down, disconnecting and reconnecting till they are completely flat.....but have read somewhere Nicds should not be totally discharged so starting to get confused with all the different info out there on battery's

[FullLeatherJacket]

Steve
You should monitor the voltage across the bulb as the pack discharges, and disconnect the pack when the value reaches 1.0v per cell (some reckon on 1.1v to be on the safe side). Any lower and you risk one or more cells going into deep-discharge for which there is really only one remedy.... it's called a disposal site 
Got your PM and replied a few minutes ago.
FLJ

[boatmadman]

Re discharging nicads:

I have, with no problems, used a diode for the relevent voltage (1.1v per cell in the pack), and resistors for load to discharge nicads.

The diode acts like a switch to open the circuit at the appropriate voltage, avoiding deep discharge.

It worked well for me.

Ian

[rem2007]

Have a look at these pages. They are pretty good at explaining the black art of motors, batteries, chargers and such.

http://www.component-shop.co.uk/html/batteries_explained.html

I found them useful when starting and refer to them when required.

[Captain Jack]

I realize the expense involved gentlemen, but for top notch performance, power to weight ratio, ease of charging, NiMH batteries and brushless motors with the appropriate brushless ESC's are the wave of the future. I use them on  my  waterjet propelled crew boat (American Enterprise), and they just can't be beat. And by the way, if you want to shop for these items, look to the airplane sites for bargains.