new boat build

[hammertime]

Hello everyone! WOW it has been a looooong time since i have been on this site. Years. Last time i was on here and built a boat the sv had just come out and lipo batteries were scary to use! I was at my lake house at the ozarks a couple of weekends ago and seen a guy with the ul-1 and it got me itchin to build another boat. I havnt built one in a long time and sold all of my stuff off when i found out my mom was sick. I have been reading some of your guys threads and wow! This hobby has done a complete 180 from what i remember! So any way im not trying to build a rocket. Mid 40s is what i would like to achieve. A couple of questions and opinions before i make any decisions. I want to build a twin cat but i am not familiar with lipo batteries so i may stick with the good ol nmh batteries. I want to run either 6 or 7 cells. Heres what im thinking

2 of these....

http://cgi.ebay.com/Water-Cool-Brushless-Motor-BL2856KV3200-150A-ESC-Boat-/400137137945?cmd=ViewItem&pt=Radio_Control_Parts_Accessories&hash=item5d2a082f19

this hull

http://cgi.ebay.com/32-fibreglass-catamaran-hull-electric-rc-boat-/290371873596?cmd=ViewItem&pt=Radio_Control_Vehicles&hash=item439b832b3c

2 sv struts and rudder

My concern is with the kv. Last time i built a cat it was a single motor 8xl on 2 7 cell batteries. It would go around 50 mph and it was a blast. I want to run 7 cells to each motor on this built. will i be pulling to many Amps with this set up? I know its cheap electrics but like i said i dont want something state of the art. Just a fun boat to run with somewhat impressive speeds. Opinions?

[ozzie-crawl]

i just got another one of these today,not bad hulls just need a bit of reinforment.
imo you should go lipo,more power,longer run time,cheaper.
mine will be twin 8xls on 4s (14.8v)
try hobby king,the turnigy lipos are best bang for buck around,i have acouple of there $18 chargers and there still working well after 18 months

[hammertime]

this shows how long i have been out of the sport. Lipos used to be extremely expensive, the chargers used to be expensive, and they had to be charged properly and discharged properly. I dont know anything about lipo but it sounds like its better than it used to be. Ill have to do some homework on these things so i can join the rest of the crowd. I like the idea of lipo, just dont know the first thing about it.

[ozzie-crawl]

yea lipos have come along way in the last few years.
your in for a real suprise not having run them before.

[Fluid]

That motor is probably too small for that hull depending on the battery you want to use. Good luck finding a 4mm coupler. Any motor/ESC combo that's only $61 shipped is probably not one that you will be happy with.

Hey, it's only been since last November that you last visited here. Glad you're back!



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[hammertime]

Fluid.. yes you are right about the electronics... its better to do it the right way the first time.. learned that the hard way a few times!!! i got on here last november to show someone a video of my bk bandit when i built it. That was the last boat i built, the last time i researched equipment, and the last time i knew anything about the hobby. Ima a newb again!! ahhhh... That was about 2 years ago at least!! so a lot has changed since i have been gone! does anyone think this would be a good idea? and then change the electronics out for some better stuff?

http://www.hobbyking.com/hobbyking/s...n_motor_(800mm)

also can someone send me a link of what turnigy batteries they would use and a decent charger.

i still need to catch up on these things.

also i noticed this boats motors spin the same way. i can just switch the polarity on the motor and it will spin the opposite way right?

[hammertime]

and if i can do this should the props spin outward or inward from the top?

[Fluid]

Simply switch any two of the three motor wires, that will reverse the rotation.

As far as which way the props should spin, I don't know - too many conflicting opinions:

http://forums.offshoreelectrics.com/...unter+rotating

http://forums.offshoreelectrics.com/...unter+rotating


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[hammertime]

thank you ozzie and fluid. I appreciate the help!

ozzie you stated...mine will be twin 8xls on 4s (14.8v)

is that to each motor? or is this one lipo battery? or is it 2s in series on each side like we used to do nimh batteries? still trying to wrap my head around this stuff

[hammertime]

Also the motors in that twin cat... are those to small to run as a sport boat in the 30s until i have money to upgrade it?

[ozzie-crawl]

thank you ozzie and fluid. I appreciate the help!


is that to each motor? or is this one lipo battery? or is it 2s in series on each side like we used to do nimh batteries? still trying to wrap my head around this stuff

yes would be 4s a side for each motor
i personally would not try that motor, have a look at fighter cats thread, think its the hotr new version (just cosmetic changes) http://forums.offshoreelectrics.com/...ad.php?t=15099

he is using some cheap out runners

[hammertime]

the stock esc's in the twin apparition posted above are 70A.... would these motors on 3s lipo be a safe bet? I know how you prop it makes all the difference.

http://www.hobbyking.com/hobbyking/s...idProduct=6676

i am not trying to make a rocket, just a sport boat to have a little fun with and be reliable. I have a personal friend i am sure some of you have heard of... Dave Scott... former ms bud offshore boat. runs turbines and 2 other gas motors. I am building this boat to look similar to his now nauti marine boat, and it is going to be painted as well. So i am just looking for mid 30s low 40s without breaking the bank.

[ozzie-crawl]

if your doing twins yes those keda motors can work,bit of a hit and miss there a cheap copy of the fiegao i think.
you could run fiegao 540L motors or sv27,blackjack,ul-1
should all see you well into the 40s. a single 9-10xl would as well
or a single 8xl will see 50 but only for short runs