Something a bit different! Model Power Boating. RC Catamaran build thread.

LuckyBenski said:
Footage looks amazing! I skipped a few bits so sorry if it's explained but I have questions -

- What's the brown stuff splooping out of the exhaust? - Excess oil that hasn't been burned. During run in/setup process we run fuel with a higher amount of caster oil. It helps protect the engine when its especially tight. When the boat crashed and the engine was screaming for that 30 seconds before I was able to stop it we're certain that the excess oil stopped the engine damage. The next time we run the boat it will be on our usual fuel which has a lower caster oil content. The engine will run cleaner and will be able to really open up then.

- How come the boat appears the shift relative to the camera? Is it a flexible mount? Almost looks like the camera leads the steering! No its just the GoPros fancy image stabilization. Next time I want to play with settings to see if I can get vertical stabilization only and leave the horizontal stabilization

- Does the boat turn left or only right? :p It goes both left and right, but it turns right better. When the boat is running faster turning performance improves.

I think you should keep the GoPro on there at all times, the first person/water level perspective is great! I once went on a trip up the Thames in a little speedboat and the photos were lovely, it looks so nice right down on the water :)
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There you go :) - glad you liked the video!
 
Feek said:
Watched that all the way through, very interesting. Is it just a case of tweaking until you get it to a state where it doesn't stall? How is the boat recovered each time?
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Typically, yes. Although we have ordered a water pump now and plan to pump water through the engine manually, that way we can set the boat up stationary in the water by holding it. This should speed up the setup process massively. Also you can't do this for long without a waterpump due to risking engine overheating and then it going bang. :)

Boat is recovered with the rescue boat. You see it in the video. Looks like a dark green bath tub with a battery powered outboard on it. We jump in it and go and get it!
 
Phate said:
This should speed up the setup process massively. Also you can't do this for long without a waterpump due to risking engine overheating and then it going bang. :)
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I've got a few friends with boats and the first thing I thought when I saw the engine running with it out of the water was that it was unusual. I was quite surprised because I know how anal some of them are about running (or not running) the engine out of the water. Yes, get that pump fitted so you don't do the overheat thing.
 
Feek said:
I've got a few friends with boats and the first thing I thought when I saw the engine running with it out of the water was that it was unusual. I was quite surprised because I know how anal some of them are about running (or not running) the engine out of the water. Yes, get that pump fitted so you don't do the overheat thing.
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You're Essex based if I remember correctly or at least in and around Essex? Our lake we go to is at Brentwood if you ever fancy coming along to watch :)

With regards the engine outside of the water. Each engine is different. In my smaller Sprint Cat I have a MAC engine and it needs the coldest spark plug you can get plus as well if its running out of the water for longer than 8 seconds or so it starts to smoke up. So no messing around with it. This CMB handles it better, although I think the higher caster content helps massively tbh :) - The water pump will help get us a long way thats for sure.
 
Phate said:
You're Essex based if I remember correctly or at least in and around Essex? Our lake we go to is at Brentwood if you ever fancy coming along to watch :)
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Thanks for the offer and I'd love to but although I worked in Brentwood for thirteen years, I live at the top end of the county and at the moment, I'm still not driving any long distances.
 
Yadda said:
Is the rescue boat RC? That would be fun. :)
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Not at this lake, but that idea has come up. Dad and I are brainstorming something like a tug boat with arms sticking out the front to "collect" and push back.
 
Feek said:
It's March, what's next?
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I am back on Saturday, going to the lake on Sunday.

When I was there last time I shredded a propshaft as there was a bit of solder in the driveshaft brass tube. oops.

Drilled that out and ordered a replacement :) - Fuel mixture we believe is well set now but it stopped revving up, so we think its an exhaust length issue. Will be playing with that on Sunday :) - Fuel mixture is the hardest bit to get right and we're there with that :)

My small outboard model boat was also finished when I was last there so I'll have a go on that as well :)
 
Phate said:
Not at this lake, but that idea has come up. Dad and I are brainstorming something like a tug boat with arms sticking out the front to "collect" and push back.
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Great stuff. I can see it has its challenges but that's all part of the fun. Just make sure that, until it's fully tested, you have a rescue boat on hand for the rescue boat. :cool:
 
Yadda said:
Great stuff. I can see it has its challenges but that's all part of the fun. Just make sure that, until it's fully tested, you have a rescue boat on hand for the rescue boat. :cool:
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Yep :D - it would be ironic.

Rescue boat would be electric, less reliability issues. Plug in and go.

Apologies for potato pic, only one I have of the Predators (small hydros) right now - mine is the green, Dads is the blue

3R7jacZ.jpg

Will get them in the water on Sunday. :)
 
Phate said:
I am back on Saturday, going to the lake on Sunday.
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I was supposed to be doing some aerial work on Sunday but the weather isn't looking great for it. I need to see how I am driving distances..... If you want to drop me a trust saying when and where you'll be, I could be tempted to pop along if the invite is still open?
 
Feek said:
I was supposed to be doing some aerial work on Sunday but the weather isn't looking great for it. I need to see how I am driving distances..... If you want to drop me a trust saying when and where you'll be, I could be tempted to pop along if the invite is still open?
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Sure :)
 
Helloooo

So after a long "forced" break from the UK (thank you COVID) I am back. So whats happened since last time?

The last update on this was the boat would not rev up properly and was sort of stuck at around 12,500rpm - which considering its supposed to hit 22-25000rpm, its around half power which isn't good. During my time away, Dad sent the engine and exhaust off to a specialist (who actually supplied the boat and hardware in the first place) to dyno and test the engine & exhaust and confirmed both were fine without any issue, so the problem was to do with the setup within the boat itself.

This Saturday just gone, a club regular and expert on this brand of engine was there and I spoke to him in advance and asked if he could take a look as it felt like I was banging my head against a brick wall, constantly trying but not getting anywhere...

So on Saturday he took a look, we ran it, and he kept saying to us to "richen" the fuel mixture. Which means to increase the fuel flow into the engine. So, for those who don't know. With RC models with engines, the general rule of thumb was, if you can see the smoke coming from the exhaust, its running "rich" if you cannot see the smoke, its running lean. In terms of performance, you can increase engine output/performance by leaning out the mixture which means less fuel and more oxygen, but sacrifices reliability.

We thought the engine was already rich enough due to being able to see the smoke. But we followed his advice, increasing by a it, sending it out, another test, no joy, bring it back, increasing the mixture, rinse and repeat...until after maybe the 3rd or so test...suddenly the engine began to light up as you would expect...

EUREKA

Cutting an already long story short...the fuel mixture was way way off, and these engines like to run very rich. So throughout the rest of Saturday and for a few hours today Dad and I were working in adjusting the fuel mixture, exhaust length, propeller height/position and now the boat is really flying! :D

After a VERY long overdue promise...

https://photos.app.goo.gl/KDH8VvAj7dCKz9rK9

https://photos.app.goo.gl/LavXehJ2w9hzfdqQ7

Couple of videos to show how its going.

The boat still has more to give. Making more modifications between now and Friday/Saturday. Also I have ordered an exhaust length adapter, which will move the exhaust to make it longer/shorter on the fly. This will allow me to have more torque in the corners to maintain power and pickup speed lost and more RPM in the straights for higher top speed. We've also got a couple of different propellers to try to see what fits this boat & setup best.

Also on Saturday I will hopefully have a GPS readout to confirm the speed, but we're guessing/hoping 50mph+ also I will put a GoPro on it to give a proper view :D

Over the moon to say the least :)
 
That's more like it! You're gonna need a bigger lake. :)

Had me worried at the end of the 2nd vid - I take it you got it stopped?
 
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