AB Marine Intimidator Endurance Boat

[Peter A]

Well it is finally finished, this year's offshore boat.
The Hull is an AB Marine Intimidator 45" mono that has been rebuilt from a gas oval racer for Offshore endurance racing.
Motor is a Leopard 5692 540kv, esc is a SK 130 HV, it will run both 10 and 12s.

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[Peter A]

A few more pics. I hope to start testing next weekend.

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[Peter A]

And this is what I started with.

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[fred 75]

Great job Peter!

[srislash]

Looking forward to this years results Peter. Great work as per usual.

[Bp9145]

That turned out very nice. . .nice work!

[Peter A]

Thanks guys. It is not quite so perfect when you get real close, but it is going racing so it will almost certainly get it's share of scrapes and dings. That's why I keep it simple! Can't wait to get it on the water.

[Peter A]

So the boat got on the water Saturday. Running a P240, same as the old boat, but on 12s, speed was 75 kph max. Unfortunately current draw is too high at around 70A. On 10s the current draw dropped to around 56 A with a max speed of 64 kph. Temps are a little higher than I like. Unfortunately I do not think the Leopard motor is the one for this job. Definiitely a lower kv and bigger prop will be best as on 12 s with a P235 speed dropped to high 60 kph but current draw increased as well. A new learning curve.
I will be looking at getting the TP 4070 440 kv 10y motor. There are, as would be expected, a few other tweaks to do on the boat as well. Other than that, the boat ran well.

[Peter A]

Well, new motor is ordered from TP, will not be shipping until Feb 12 though. I guess they have to make it! More parts ordered also from OSE. I will update when things have been able to progress.

[785boats]

Hi Pete.
I would have thought that a 6 pole 56 series motor would have been more efficient (current wise) than a 40mm 4 pole motor of the same kv rating.
Is this not the case?
We are thinking of starting an endurance class at our club. I was going to try a 6 pole 56 motor of 500kv.

[Peter A]

Hi Paul
The Leopard is too high in kv when trying to match prop to the boat on 12s. On 10s it was close, perhaps would have been right for amps but for the thrust bearing behind the collet that was disintegrating! However from what others are doing on 12s I think I need a lower kv to turn the larger prop this hull needs to be efficient. For me the average current draw is more important than overall speed.
When the going gets rough, and I run against petrol offshore boats, I can hold my own. For all the boasting about top speeds, the gassers are only averaging around 70 kph tops on open water, and I managed to keep up pretty good in the rough. My Osprey really held up well in water that was up to two foot waves against the gassers, taking out 5th of 19 at the biggest event last year. I had propped down and was running 1/3 to 1/2 throttle, battling much bigger boats of which some seemed to try and take me out!

What sort of setup and race duration are you guys looking to run?

[785boats]

Sounds like a great result against the gassers.

We are not sure on the run time or max battery capacity yet so it is still all up in the air at the moment. Still in the "talking about it" mode.
I have an Osprey or a big cat I can convert. We are all trying not to spend too much money & use the boats & battery packs that we have.
One of us will have to set one up & see what sort of run times we can get with different battery configurations.
Bear in mind that we are not racing against gassers & it is only within our club.But we are still governed by the AMPBA regarding max voltage & battery configuration.

[Peter A]

My Osprey went great with a TP 4060 580 kv on a P240 prop. Speeds 65-70 kph and current draw at 50A. With 10s 20000mah that gave 20 min runtimes, 16000 made 15-16 min. I am unsure of the AMPBA rules, but going electric endurance will take you out of that box if you want 20 mins races. Going to lower kv on 12s will give longer runtimes. I am not sure that the 56mm can motors will run a low enough current draw, and 40mm can motors fit existing mounts in most boats. An extra reason for going for the 4070 motor, I can always put it into my Osprey if needed and run that.
I have to say though, this is quite a fun way to change up FE boating. The concentration needed to run longer races, albeit at lower speeds is a challenge at times.

[Peter A]

Look what turned up yesterday direct from TP Power.

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Will get some plugs on it and installed on Saturday. I have already fabbed up and installed brackets for the OSE quick change mounts, so it will not take long to install. Hopefully I can get back to testing next week.

[Peter A]

Got back out on the water on Saturday with the new 440kv motor installed. Running a Prather 245. Max speed 65kph, ok. Temps, motor and esc maxing around the 30*C mark with batts just a couple of deg higher. Ambient temp aroung 23*C. Boat ran well, first did a ten minute run, then a 20 min. I am using the RCM telemetry and it helps me keep an eye on temps and batt cell voltage. Average current draw at 52 amps. A nudge above what I want to achieve but I might be able to reduce that by changing the stuffing tube as it gets rather hot, even though it is greased and has a pressure grease system. I think the length is part of the problem. If I move the motor back much further and reconfigure the inside setup, I can get the CG a bit further forward using batts only with out using more weight, and possibly reduce some of the weight that is in the boat. A lot of work on a new setup, but might be the best result. Option two is change the stuffing tube to one that is a bigger diameter, which is much less work but possibly not the better end result.

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