Proboat Veles 29 being used for NAMBA P.LTD. Hydro racing, drawing too many amps

[Killswitch]

My racing history is Nitro/gas so forgive me as electric is still a work in progress.

My son it getting his first season of racing in with a Veles 29 cat in NAMBA P.LTD. Hydro racing. Yes hydro... This class runs on Sunday(I am not available Saturdays) and several cats are driven by junior boaters along with a couple of seasoned vets racing riggers. Sort of like a Prototype/GT mixed format race.

The Veles has the stock Dynamite DYNM3831 2000Kv 6 pole motor/ Dynamite ESC (no visible spec but it is the same blue as the motor) an upgraded dual water pick up rudder, upgraded flex drive and the sharpened and balanced prop available on the OSC website:

Prop Specs: Similar to ABC 1716-17-45 prop.
Diameter: 43.1mm (1.70") diameter
Pitch: 1.6 pitch
(same specs as the stock prop)

The boat is as fast/faster as any of the other cats, most of which run Leopards. The issue is battery duration.

It is running on 2 2S 5000 mah lipos and it will barely make the 6 laps for a race finish or hit the ESC min limit at 5 3/4 laps and stop before limping across the finish. The batteries were coming out quite warm and between 15-11%. Ouch...
2 different sets of batteries were used for the races. Turnigy nano-tech 5.0 35-70c and RevLectrix Blend420 Go Pack Silver Label 70C with similar results but the Turnigy lasted 3-4% longer in both of their races.

Love the prop but it is drawing a lot of amps. The motor and ESC are never overly warm, XT90s with good wire and solder, with the dual cooling lines it seems to be handling the loads so far.

I raised up the prop about 1/16 for the last race but it seemed to have zero effect on boat speed or battery lift. Likely I didn't move it enough to have an impact.

What is the right move to not only finish 6 laps but have enough for a 7th if a buoy cut is involved?

Specs for P.LTD are:
11.10 ‐ 16.92 V
10,000 mah max.

Bigger lipos are not an option as I am already at 10k.
Never considered/don't know enough to go to a different voltage but I guess going up to 3S is an option? Good or bad option?
What is the best trade off to get more run time?

What would be a slightly smaller prop that the OSE prop?? What about a 3 blade prop? 645/3 was mentioned somewhere on this forum.
Diameter: 43.1mm (1.70") diameter
Pitch: 1.6 pitch
Similar to ABC 1716-17-45

[Peter A]

Try an M445. Even better is a Dr Props 447 for current draw.

[tbonemcniel]

Actually, you're only using half of the allowed 10,000 mAh capacity.

You have 10,000 mAh capacity at 8.4 volts (2S Lipo's fully charged to 4.2 v/cell), but since you are running the batteries in series, you only have 5,000 mAh capacity at 16.8v (4S Lipo fully charged to 4.2 v/cell).

As per the NAMBA rulebook, "For the purposes of determining maximum allowances, a “pack” will beconsidered any number of cells in series whose min/max nominal voltage fallswithin the allowed nominal voltage range for the designated class."

So you have two options. You can run up to 2x 10,000 mAh 2S LiPo's in series, or run 2x 5,000 mAh 4S LiPo's in parallel. Either way gets you more mAh capacity for longer runtime.

[Killswitch]

Oh..... Snap.....

OK so now the question is how much larger to go and make it to the finish but not be needlessly heavy.

The previous batteries at 5000mah barely made it but are a good bench mark. They came back at about 11-14% after a race so use 10% as a baseline. 4500mah used for 7 laps = 650mah per lap approx. Planning on the lipos finishing at about 25-30% then 2 x 2S 6000 would mean around 1500mah would be about 25% which leaves 4500mah useable for racing. 650 x 7 = 4550 + 1500 = 1650. 2 x 2S 6000mah lipos look to be about right and I can keep the prop and set up as is... Sweet!

[tbonemcniel]

Oh..... Snap.....

OK so now the question is how much larger to go and make it to the finish but not be needlessly heavy.

The previous batteries at 5000mah barely made it but are a good bench mark. They came back at about 11-14% after a race so use 10% as a baseline. 4500mah used for 7 laps = 650mah per lap approx. Planning on the lipos finishing at about 25-30% then 2 x 2S 6000 would mean around 1500mah would be about 25% which leaves 4500mah useable for racing. 650 x 7 = 4550 + 1500 = 1650. 2 x 2S 6000mah lipos look to be about right and I can keep the prop and set up as is... Sweet!

Bingo. 2x 2S 6000 mAh will probably fit the bill quite nicely. I personally use 2x 2S 6200 mAh 100C batteries in my P-Limited Catamaran and P-Limited Sport Hydroplane.

[ray schrauwen]

10K won't hurt at all. The weight is no issue and can help. The extra fuel is always good and keeps the nominal voltage under load higher.

[Epoweredrc]

Just wondered if this is a normal IMPBA class or just something your local pond has, I just picked up the same boat as something to play around with. never thought they might be a class for it. I am thinking already i might have to do the same so i can get longer run times out of it.

[Killswitch]

Just wondered if this is a normal IMPBA class or just something your local pond has, I just picked up the same boat as something to play around with. never thought they might be a class for it. I am thinking already i might have to do the same so i can get longer run times out of it.

It is a NAMBA class. Due to the hydro classification, cats can run in the same class as several other styles of hulls.

From the NAMBA Rules Book: HYDROPLANE HULL1. If a hull does not meet the requirements to be classified as a monoplane then it isautomatically classified as a hydroplane. Examples of hydroplanes: Catamaran, tunnel, tunnel vee, sport, scale and outrigger.

Outriggers are the fastest of the allowed hulls so that is the default kind of hull you normally see run. Myself and a couple other boaters can only race on Sundays and we wanted to get our kids into boating at a low cost entry point and this was the answer for us. I was worried the guys who run the riggers would complain about the junior boaters but it is seen as another part of the race for them to take onto account. They usually finish 1-2 laps ahead of the rest of the cats so lapping the field twice while dueling against other riggers added more challenge to what a class that was always light in entries. The jr. boaters, being well coached, are also very good at holding their line and not getting in the way of the riggers. The cats are normally on the same lap a straightaway apart at most and run some very close deck to deck racing.

The one trick I have learned with this hull is that the rudder needs to be kicked forward just a tiny bit to keep it barrel rolling in the corners. That small amount of angle in the rudder adds downward pressure to the right side of the hull and keeps it stuck to the water.

[Peter A]

It is a NAMBA class. Due to the hydro classification, cats can run in the same class as several other styles of hulls.

From the NAMBA Rules Book: HYDROPLANE HULL1. If a hull does not meet the requirements to be classified as a monoplane then it isautomatically classified as a hydroplane. Examples of hydroplanes: Catamaran, tunnel, tunnel vee, sport, scale and outrigger.

Outriggers are the fastest of the allowed hulls so that is the default kind of hull you normally see run. Myself and a couple other boaters can only race on Sundays and we wanted to get our kids into boating at a low cost entry point and this was the answer for us. I was worried the guys who run the riggers would complain about the junior boaters but it is seen as another part of the race for them to take onto account. They usually finish 1-2 laps ahead of the rest of the cats so lapping the field twice while dueling against other riggers added more challenge to what a class that was always light in entries. The jr. boaters, being well coached, are also very good at holding their line and not getting in the way of the riggers. The cats are normally on the same lap a straightaway apart at most and run some very close deck to deck racing.

The one trick I have learned with this hull is that the rudder needs to be kicked forward just a tiny bit to keep it barrel rolling in the corners. That small amount of angle in the rudder adds downward pressure to the right side of the hull and keeps it stuck to the water.

I'm pushing the Like button on this. Sounds like a great bunch of boaters.

[Brushman]

Hello, I have a Veles 29

to reduce the consumption and inscrease speed, you could install this rudder blade:https://tflnorthamerica.com/product/...r-blade-115mm/. you will need to rework it a little and to add a spacer to compensate for the finner blade. For the cooling: cool the ESC first and increase the diameter of the water outlet with a drill bit to nearly match the internal diameter of the cooling lines.
You can use 2x2S 5500 or 6000, but for a similar weight or close 2X4S 3600 SMC in parallel: https://www.smc-racing.com/index.php...product_id=634.
I would try a 1616-17-45 ABC, or a 1814-17-45.

Vincent