Disappointing day at the lake..... Help needed.....

[JCAustralia]

Hi guys

As the title say it I had a disappointing day at the lake with my new Phantom catamaran.

First I went to a new lake. My research on the internet says that its a big lake and people do swim there.

Upon getting there I got my first disappointment. The lake is half dry and the water is muddy and looks dirty. There was nobody swimming also.....

Anyway I decided to try give my new 29" Phantom cat its maiden voyage despite the initial disappointment about the lake. There was a light wind and the water was near smooth.

Did some testing to make sure everything was working and was happy that everything was working properly. Was pretty excited when I put the cat on the water and seeing how she float gracefully on the water.

I was expecting that when I would press the throttle the boat would get on a plane soon......

I did press the throttle and the cat lept forward...... then it just kept going 5-10 mph and does not get on a plane. There was plenty of cavitation with load of bubble at the back of the cat......I did that for like 10 minutes and decided to give up on the cat today.


What do you think is the problem?

The cat is an ebay 29" Phantom cat. I'm using the SV27 motor and ESC with 2 packs of 6Nimh cells. Hardware is from Ebay also.

To make the day more disappointing I got caught in the mud on the lake bank and lost one of my slippers.....

Here are some picture of my boat. Please tell me how I can get it on a plane and avoid cavitation.

Thanks

JC

[Fluid]

We need more information....

- exactly what prop are you using?
- where is the CG on your cat?
- how far above the bottom of the sponsons is the strut?
- does the driveline rotate freely with minimal drag?
- how hot did the motor and packs get when you finished running for ten minutes?



.

[screwball]

also were the packs in series or parrallel and what MAH?

[Doby]

Please don't say they were Venom packs,,,if they were, thats a LARGE part of your problem.


More info please.............

[785boats]

Sorry to hear about your disappointment, but if you had managed to get the boat to plane you may have been in for another disappointment too.
This was my experience.
I have recently bought a Sea Predator with the same hardware on it as the gear on the back of your hull.
The water pickup on the bottom of the strut not only forces water in around the bearings & up through the outlet, but also forces water up the drive line & into the boat. I had a cup of oily water in my boat after each of its first two runs before I worked out what was happening.
I immediately went home & manufactured another pickup & blocked up the existing intake with a bit of silicone. No more problem.
I tell you this so you can avoid the problem or at least be aware of it.
I see you have already installed a separate pickup on the transom so you are halfway there.
Of course yours may not have this problem.
Someone will help with your cavitation problem once you answer the questions posted earlier.
Here's a couple of pics to show the original pickup & the new one.

All the best.
Paul.

[Flying Scotsman]

We need more information....

- exactly what prop are you using?
- where is the CG on your cat?
- how far above the bottom of the sponsons is the strut?
- does the driveline rotate freely with minimal drag?
- how hot did the motor and packs get when you finished running for ten minutes?



.

10 minutes??? wow this guy has a problem, answer the questions posed Jerome!

Douggie

[JCAustralia]

We need more information....

- exactly what prop are you using?

I'm using a 2 blades plastic prop from HOR. Its hard and the diameter is 3.5 cm (1.4 inch). I did used the blade previously on my SV27 successfully.


- where is the CG on your cat?

COG is at 32% of the CAT.


- how far above the bottom of the sponsons is the strut?

The centreline of the strut is more or less aligned with the bottom of the spoonsoon.

- does the driveline rotate freely with minimal drag?

Yes it does rotate freely. I did put plenty of grease and did lots of testings. Everything is aligned and the stuffing tube has a nice gentle curve.


- how hot did the motor and packs get when you finished running for ten minutes?

Did not get the temp straight away after taking it out of the water. But after say 5-10 mins the motor was 80 degrees celscius. Battery and ESC were also hot to the touching.... Not sure how much Farenheit this is, sorry....



.

The battery I'm using are in Series and I have 2 sets of 2. One set is from CheapBatteryPack, about 18months old, the other one is brand new from Ebay.....

Also this boat is pretty heavy and I guess that it is designed for nitro use mainly with the stringers and heavy weight.

I suspect that the weight is a big part of the problem.....

Thanks a lot for your comments and help. Keep them coming.

Cheers

JC

[Gerwin Brommer]

Is the coupler tightened enough ?
Or : propshaft/flexshaft : can you turn the prop while you block the coupler ?
the packs are parallel ? not in serie ?????
7,2 Volt on a 35mm prop for such a heavy/large cat ???

[JCAustralia]

Oops

Battery are in series....

Thanks.

[Mel279]

hey jerome888business

don't use that superpower nimh batteies, sorry to say they are a piece of crap, you won't go fast with it and bought two of 5000mah nimh for my friend and he was really disapointed with the performance and runtime was too short

[ozzie-crawl]

lift your strut so the bottom is 6mm (1/4") above the sponson bottom
angle the prop up 1-2 deg

[Flying Scotsman]

Your voltage, prop, power source are your problems. Step up to an Xl motor, an ESC that will take 100 amps as a minimum and an X440 prop as a start point, 4S li-po batteries 5000mah

Douggie

[m4a1usr]

Is the motor spinning the prop counter clockwise. A reverse spinning prop could be your problem. That would generate almost no thrust, hence no speed.

John

[Fluid]

Battery issues aside, the prop is 'way too small for that motor, and it is running too deep. The giveaway here was the severe cavitation.

- Try props between 40mm and 45mm in diameter with a 1.4 pitch ratio.
- Raise the strut so that the bottom of the strut is 5mm above the bottom of the sponsons.
- Angle the back of the strut up one degree.
- Move the packs around to get the CG 230mm ahead of the transoms.

These should get the boat on plane, as long as the packs are half decent. But realize that you most likely damaged the motor by running it for ten minutes - 80C is 175F which means certain magnet damage. The motor may never perform correctly again....or it might work, hard to say.




.

[ozzie-crawl]

i used to have one of these hulls there heavy, i was running a 580 L motor