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Author Topic: Hi Tec Sea Nymph  (Read 3895 times)

meechingman

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    • Andrew Gilbert
Hi Tec Sea Nymph
« on: April 19, 2007, 05:39:06 PM »

Hi

Dunno if this is really 'fast electric', but SWMBO wanted a faster boat than her 'toy' RNLI Severn. Spotted a Hi Tec Sea Nymph on Ebay for a cheapo price. Arrived today, works as advertised. Much better than the current cheapo chinese toys, with a proper Futaba/Hi Tec r/c system, at least!  :)

Anyone have any knowledge, experience, tips etc. Motor is a Mabuchi 550 driving a 35mm prop- anyone know if this is goo or bad? Looks like I could replace the mechanical speed controller with and ESC and go from the plastic prop to a brass one with no problem, but would it be worth it? At the moment I've borrowed an 1800maH 7.2v Tamiya pack from my son's car to power it. Any idea how long that might last on the water?

Cheers
Andy




updated with motor details and pix
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Bridkid

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Re: Hi Tec Sea Nymph
« Reply #1 on: April 22, 2007, 08:44:59 AM »

Hi Andy.
What you have got seems to be a good starting point. Maybe a different motor and prop is worth trying although I don't know anything about the Sea Nymph. It looks pretty bog standard from the pics but I have never seen one run. You could try a 540 'buggy' type motor (21 turn or similar and a 31mm metal prop although you would then be getting into the realms of requiring water cooling. Also decent metal props are hard to come by and cost around 12 each. ASTEC and Prestwich Models sell them but the Prestwich ones need a lot of work cleaning, sharpening and balancing.
The 1800 pack will probably (that's just a guess) give you around 4 or 5 minutes run-time but if you upgrade to say something around the 4000MaH you will get far longer, but remember, longer run-time = hotter motor! If the present set-up gives SWMBO some fun and a decent run-time then I would be tempted to leave well alone......unless she turns into a speed-freak!!
Cheers,
Ian.
 8)
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meechingman

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Re: Hi Tec Sea Nymph
« Reply #2 on: April 22, 2007, 12:12:58 PM »

Thanks. On her first run out yesterday, I was very pleased with her. Fast enough for SWMBO and turns sweetly - stays pretty flat. A little water ingress - stuffing tube, most likely, so that's got to be fixed. Prop change - maybe later, if she wants to go faster!

Bigger capacity battery is next up, to give me/her a few short sessions. 6 mins is what we got from the 1800 pack, so one or two of Modelpower's 3300 or 3700 packs will do nicely.

Even my son was impressed, he now wants a 'much faster' boat, so we've got a new convert to the hobby.

Andy
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Bridkid

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Re: Hi Tec Sea Nymph
« Reply #3 on: April 23, 2007, 08:03:40 AM »

'Even my son was impressed, he now wants a 'much faster' boat, so we've got a new convert to the hobby.'

Excellent news Andy, we need all the 'converts' we can get......especially to the 'faster side of boating.
Have fun and enjoy!
Cheers,
Ian.
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Daniel

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Re: Hi Tec Sea Nymph
« Reply #4 on: April 25, 2007, 09:21:19 PM »

Hi meechingman,
I would go with the brass prop.
In my club 500 I am running 2300mAH ni-cd 7.2v batteries which will last maybe twenty minutes each so if your looking for a longer running time I would upgrade the battery

Thanks
Daniel
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meechingman

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Re: Hi Tec Sea Nymph
« Reply #5 on: April 29, 2007, 06:46:12 PM »

Second outing for the boat today and remembered to take the camera. Got a longer run time, so maybe the battery wasn't fully charged last time.

More water ingress, this time from the rudder tube. Anyway, she's OK, back home and in bits, ready for some replacement sealing washers, a little grease in rudder and stuffing tubes, and a new brass prop. Someone said you had to polish and sharpen new brass props. Is this really so, and how do you go about this please?

Sea Nymph 1


Sea Nymph 2


Cheers
Andy
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Bridkid

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Re: Hi Tec Sea Nymph
« Reply #6 on: May 01, 2007, 08:32:40 AM »

Hi Andy.

If I have a brass, or any metal prop come to that, (for a fast electric) I always balance, sharpen and polish it. You really need a prop balancer but in my early days used to use two razor blades stuck in a balsa block then put the propshaft and prop across the razor blades. If the prop is out of balance then the heavier blade will 'roll, to the bottom so you take it off and file some of the blade thickness off until both blades balance. (hope you can understand that) To sharpen the blades only do the leading edge not the trailing edge, this will help the blade cut through the water, and as far as polishing is concerned, I use some fine grade wet 'n dry and then solvol autosol or similar. It's a bit of a black art I'm afraid with all sorts of tricks and different 'cuts' that you can try depending on the type of prop, but keep it simple and the performance should improve. Looks well on the water by the way. What type of prop did you get?
By the way, I wouldn't recommend grease on the propshaft...........causes drag, the enemy of speed and endurance, I always use very thin oil such as sewing machine oil or the stuff you get for model trains.
Cheers,
Ian.
 8)
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Bridkid

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Re: Hi Tec Sea Nymph
« Reply #7 on: May 01, 2007, 08:37:35 AM »

Just another thought after re-reading my post. When you sharpen the leading edge, only do it from the convex face......ie. the one that faces the bow of the boat when it is in the tube.
Cheers,
Ian.
 8)
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meechingman

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Re: Hi Tec Sea Nymph
« Reply #8 on: May 01, 2007, 08:44:27 AM »

Thanks, your explanation was crystal clear. I have some Hammond Organ oil for my Hammond, that's better than 3-in-1, so I'll use that for the shaft. Putting the box away in the loft yesterday, I read on the side that she's actually designed for 8.4v rather than 7.2v. So that's what I'll order for that extra turn of speed. All I need now are some new thin rubber washers to seal the outside of the rudder tube where it enters the hull. Any sources, anyone?

Andy
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Bridkid

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Re: Hi Tec Sea Nymph
« Reply #9 on: May 03, 2007, 08:00:48 PM »

Hi Andy.

I used some tiny little 'O' rings I managed to find in my local DIY store. You know, one of those places that have loads of everything on ald shelves......not the 'B&Q buy 6 even if you only need 1 packaging'. You could try cuitting some silicone tube (water cooling type) if you can manage to cut a straight edge! I use that sometimes but can't cut it straight. By the way I never bother to oil the shaft, just the bearings at either end and on the motor. I always take the shaft out when I get home and rub it with an oily rag then store it ready for next time.
Hmmmm, Hammond organ eh, mine was a Lowry but I swapped it and bought a Korg Trinity, takes up less space!

Cheers,
Ian.
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