Miniflyer

Hi Guys

I'm sort of "new" to boating, i'm more from the RC aviation section, but have decided to get into speed boating as well. At least it's something you can do while sitting at the lake with the woman :-).

I sort of like catamarans and have narrowed my search down to the following 2 from Graupner (best availability here in germany):

http://www.hobby-lobby.com/keywest.htm
http://www.hobby-lobby.com/systems.htm


Now while both have reccomended powere pacages, i have noticed that these are not really top speed oriented. My Brother has a Graupner Arrow running with stock setup, 2 Speed 700 geared to one screw. Looks like this:



It really doesn't move a lot...so i don't even want to bother buying the stock type for my boat.
My question is: what setup would you reccomend to get the Key West or Systems moving out nicely? Say somewhere in the 30-40mph would be nice.
I have a 55A marine controller goofing around already, but would also consider brushless.
Would you go single or twin screws? Brushless or brushed? What motors and screws do you reccomend for the performance i'm looking for?
Sorry if there's so much i'm asking, from the planes i know that there is a lot one can do wrong by choosing a wrong setup, and i wanted a good and glitch free start into boating.

Best regards
Hank

CadillacDTS2001

brushless is they way to go , but i think 30 -40 mph is way out of the hull speed for that boat ! ,
i would be surprisded for the boat t hit 30mph
you can go with a ss1 cordite 700 on 12 cells , that in a hydro will hit about 34 mph or so !
, get a brass prop and a wire or flex shaft drive!
a jeti esc , and some of the other goddies ,
deans plugs , better rudder and motor strut ,
so basicly all you are kepping is the hull !

Miniflyer

I've read on forums that people have hit 60km/h (so around 40mph) regularly with this design...they just beefed up the interior with glass and made a sharp edge.
Apparently the "Systems" already hase a molded-in step and is a better handler at high speed....needs more power though. I'll be seeing if i can get my hands on a set to tweak for a fair price.....

One thing i see a lot: people are running the 10-12 cell motors on up to 20 (!!!) cells....from the aviation section this is a severe no-no (heat disipation). Does the water cooling help so much that these motors can take so much more beating, or are they simply loaded less on the smaller props?

How about LiPo in boats? Does the less weight help or is it rather bad for the boats?

Thanks
Hank

pompebled

Hi Hank,

If you can read German and check the forums in the link, you'll realize your looking at rather outdated "plastic fantastics" in terms of speed and design.

Check out :

www.hydromarine.de
www.hopf-modelltechnik.de
www.mhz-engines.com

Just to name a few and these two forums (a.o.):

www.rc-raceboats.de
www.hydroworld.de

The boats you mentioned are suitable to "sit by the lake with the woman...", the boats these guys run, will need all your attention, at least for the duration of the runtime.

Regards, Jan.

Miniflyer

Hi Jan

i am aware that these will not be racing machines. That's also not wat i want.....60-70mph is definetly not what i'm looking for. I just want something faster than the stock setup, because it's really crawling around....
From the forums you posted, i gathered that a hot 700 noedymium motor with 14 cells is the best way to get decent performance without stressing the plastic hull too much. I think i'll go with that, since i already have the controller gathering dust in my basement.

Best regards
Hank

Quicksilver

quoting another forum

I think the ABC super Hawaii is often called a cesa as well. Whether you have the cat or the large mono, replacing the motor with a 700 sized can is usually a good start. The cat is around the same size as my Graupner Key West and it runs well with a 700, 12 cells and a octura x438 prop. Without knowing the hull though I can't really say too much. The ride surface, stability at speed, and the type of driveline used are all important factors. Read, read, read. The books sold by airage are invaluable resources http://www.rcstore.com/rs/general/li...d=16&catego=BO John Finch's book on advanced model boating is excellent although quite technical and contains nothing on electrics. Jay Turner's book called The Basics of Fast Electric Boats is also excellent and is a great place to start for info on modifications. If you want to talk to Jay Turner(he's a genius with brushed motors) he is a moderator on Rumrunner.com. Also if you have a question for John Finch(he's a boat setup master, especially monos) he frequents rcboat.com

The best place to start for modifying all beginner boats is new prop, new motor, new esc. Fine design sells octura props online here: http://finedesignrc.com/ The owner Chris Fine is a super knowledgeable guy and could probably help you a lot, but you basically have to phone him, email isn't his thing. He also knows lots about 700 motors and sells them.

The most popular esc's for electric boats are made by rchydros.com. Totally water proof and water cooled, tough as nails and great service. http://www.rc-hydros.com/

Try searching the rumrunner.com forums I'm sure they'd have info on the boat. It's the best place for info on electric boats anyhow all the best electric boaters are members there.

These came up when I looked for cesa http://www.rumrunnerracing.com/fefor...der=descending

Here's the RCBM review of the CESA Catamaran http://www.rcboatmodeler.com/RB/reviews/cesa.asp










this is from
http://forums.radiocontrolzone.com/a.../t-104073.html

pompebled

Hi Hank,

That's fine with me, I merely wanted to point it out.

If you go for either one of these cats, please(!) don't aquire the Graupner running gear, it's not very good, to put it mildly.
Get a flexshaft with strut and rudder from Hopf, or H&M, or Gundert, and you'll be much happier with the performance.

I've seen a 700 motor eat the Systems outdrive in a matter of three runs...

If you go for the Key West, check out the German forums how to remove the brakes at the end of each sponson, Graupner has 'designed' on, because they frustrate any attempt of making the boat go faster.

Regards, Jan.

Miniflyer

Thanks Jan for the great tips and links. I'll be looking into it, and see if i can get something together to have fun with. :-)
Best regards
Hank