MOVMX Racer

Hey all,
I was out driving the other day and noticed this fiberglass behemoth sitting outside of my neighbor's house and decided to stop by and ask about it. Long story short, I now have this 92" monster catamaran and have no idea what to do with it. From what I have uncovered so far, it looks almost identical to an HPR 233 ([link=http://www.hpr-powerboats.com/gallery/hpr-233-gallery/]LINK[/link]), but this one is fiberglass and could be a knockoff?

Anyway.

I have been out of the RC scene for a few years now except for my little HeliMax CX micro that I use to terrorize house guests. This means that I have a lot more questions than I can find answers for. My last foray into boating was a Supervee 27 Nitro that was a blast until $35/gal nitro and a snapped rod retired it.

So now I have this enormous boat and no idea what to do with it. I know I want to finish it and show up to local lakes and have an R/C boat the size of other people's jet skis. My problem is how to go about this. I am a college student, so funding is tight. This definitely wont be some 2x 2 cylinder inline gas build or anything.

So far, I am torn between electric and gas. I like the ease of electric with just charging it up and going, but the amount of time charging batteries with enough juice to move this thing might just be too much. Also, batteries seem to be really expensive still. Would it be possible to power something like this with a couple brushless motors and some gel cell batteries, or is lithium the only way to go?

Is there somewhere to find gas engines for this that aren't like $300 each? Some weedeater or chainsaw line that would be useable with a water cooled head?

Where do I even look for hardware of this scale? Can I buy premade stingers/rudder for something of this size?

I am hoping to see decent speed out of this thing, maybe 40-50mph if that isn't unreasonable.

I have no idea where to start, so ANY information/links would be greatly appreciated.

I can't get photos to upload at the moment, but will throw some up later.

THANKS!

Ron Olson

My Feedback: (1)

I don't know how many times that I've thrown a budget out the window, probably on every boat that I've built!
It could be a clone hull as there are some around that big but not many.
OK, to the budget. Forget the weedie or chainsaw engines as they're more hassle than they're worth. Building cheap you could look at the Rev-Unlimited engines from www.gizmomotors.com . Stock engines dirt cheap and the modded ones for less than many of the name brand stock mills.

MOVMX Racer

I hear you on the budget plan. That is precisely why I never listed an actual number, knowing I wont meet whatever I set. I will come up with a budget after the build is done that is more than what I spent so I will feel good about it.

I checked out that link for the Rev Unlimited motors, but it seems that every model is out of stock! I could definitely swing for a couple of the 29.5cc stockers! Would 2x of those 29.5cc engines push this boat at a good clip? HP rating on the mod 28.5 is 5.8hp. I would assume that with a good pipe and maybe some intake/exhaust port massaging the 29.5cc could hit pretty well. Is the cylinder design/porting on this anything like a 2-stroke dirt bike engine? What is a good horsepower to aim for to push a boat this size?
Also, would a gas engine need a gearbox to hit the 30,000rpm mark that I keep seeing for boats?


Maybe I should just sell my car and but a couple of jetcat turbines for it.

Here are a couple pics, and yes that pond in the background is ours (my parents, who I live with in the summer). It would be my primary body of water, but there are a few local lakes to go to as well.

w3bby

"92" catamaran" and "tight budget" are two phrases that do not sit well together. However you power it the boat is going to cost money.

To give you an idea here is a link to [link=http://www.mhz-powerboats.com/Hulls/category-31/Mystic-C5000-Glas-1850mm-72-8-.html]MHZ, their 72" hull.[/link] They also have a 94" mystic but do not have an electric recommendation for that. This should help with your budget calculations.
Others doing hardware for the large hulls are [link=https://www.mtc-powerboat.de/index.php?lang=en&section=3]MTC,[/link] [link=http://wd200-modellbau.de/]WD200,[/link] [link=http://www.horracing.com/index.php?cPath=49_55]HOR racing[/link] to name those I remember.

Ron Olson

My Feedback: (1)

I don't know where you're getting the 30K RPM at, maybe from nitro boats (?) but the gas engines aren't turning that kind of RPM yet.
Probably turbines would be about what you'd dump into an electric setup as the battery packs alone would be a small fortune! Add in the ESC's and beer can sized motors the gas engines start looking a lot better.
Right now the boat has the Rat Rod look going on. One of these days I want to build a boat that looks beat to Hell yet runs like a scalded dog.

MOVMX Racer

I think I came across the 30K rpm thing when looking at electric power. I did some research into electric and it looks like at least $500 batteries alone, and then it would be another $4-500 for motors and escs ; by then, I may as well put in a couple inline gas engines!

Really the only uncertainty I have left is how much power I will have to squeeze into the hull via gas engine to get this thing up on plane and doing a good speed.

I will probably move this on over to speed/gas when I get home today and get a build started. I do have access to an ABS printer, so I might try to prototype some mounts/driveline hardware to see if it is feasible to fabricate on my own.

I do like the idea of a rat rod boat, but I'm also quite partial to the Miss Geico, and might have to do a paint scheme to match.

Justaddwata

My Feedback: (3)

Guess the question will be - what is your budget. In all reality this might be a build that will have to wait until your budget grows.

Big cats are not budget friendly. There are gas options that can make it a little better but realistically it is still not going to compare with most gassers out there - it is a twin build so there is going to be added complexity too.

You have the hull - it is realistically the most inexpensive part. Hardware will set you back $1000+, motors, pipes, clutches - $1800+, radio, paint and other finishing touches - $1000+
Dont overlook the fact that this is not a beginner build or beginner model to run.

The hull you have looks like it probably came from Mark in Vancouver - he is a thief of sorts when it comes to the quality of the boats he was selling (5-8 years ago). Quality was HORRIBLE and all the hulls he shipped required extensive work to make them usable. Looks like your hull has had some work done but not sure if finished or not. Believe I communicated a few times with the likely former owner.

Take a look through this album (Build Pics and other peoples builds albums) for some ideas on what and how to approach your build. There are a few great builds in the build pics!

MOVMX Racer

Well so far, I have found quite a few areas of the fiberglass that need some work. It seems like whoever had it before me added some fiberglass cloth to the tunnel and sponsons where any radio equipment/motors would mount and then added filler to most of the hull to fix imperfections. I believe I will probably grab either some heavy fiberglass cloth locally or order some CF/Kevlar to layer on the inside as far as I can reach. The hull seems to be solid on the sponsons, but it has too much flex everywhere else. There are also a lot of little imperfections on the surface that I want to fill.

As for hardware, I will probably grab some cheap chinese made stuff for now. The drives are the hardest thing to locate though. I found this online [link=http://www.ebay.com/itm/108mm-adjustable-stinger-drive-for-3-16-prop-shaft-for-rc-boat-/140797161280?pt=US_Radio_Control_Control_Line&hash=item20c82a2f40]Drive[/link] , but the drive is about 70mm too short. I am thinking I could grab a couple of those and fabricate a longer strut tube for it to make the drives around 180mm. Otherwise, WD200 is the only place with arneson style drives long enough, but they are almost $200 a piece.

I also found these, which seem to be domestic (ships from IL). They are 175mm end to end, which SHOULD work? [link=http://www.ebay.com/itm/Arrow-Shark-SR512-Extended-Stingray-Drive-State-of-the-Art-Stinger-Drive-/271211552052?pt=US_Radio_Control_Control_Line&hash=item3f2577dd34]Drives[/link]

I will probably use a rudder like this one:
[link=http://www.ebay.com/itm/alu-short-arm-rudder-w-dual-water-pickups-for-rc-boat-/140450735317?pt=US_Radio_Control_Control_Line&hash=item20b38424d5]Rudder[/link]

And then I am wondering if one of those rev-unlimited engines would fit in this mount: [link=http://www.ebay.com/itm/CNC-aluminum-engine-mount-with-clutch-for-Zenoah-marine-engine-rc-boat-/130901336858?pt=US_Radio_Control_Control_Line&hash=item1e7a53e31a]Mount[/link]

I think for now I will go with cheaper components in order to get it running and in the water for as cheap as I can. I only have this summer to work on it before I am back down at school, so there is absolutely no way I could manage a $3k build on this thing in that time. I MIGHT be able to squeeze like $800. Fortunately, I have all of the electronics I need already minus a battery and cutoff. I am not aiming for all out speed here- I just want it to get on plane and look cool; I don't need a 70mph boat right now!

w3bby

You have no links to what you propose to use....
You want to use a 1/4" flex and propshaft for the driveline.
Your engines will be mounted in the sponsons so you will probably find that standard motor mounts won't work. A link to see how others have done it [link=http://www.rcuniverse.com/forum/m_8977354/anchors_8977354/mpage_1/key_twin%252Cengine%252Ccatatmaran/anchor/tm.htm#8977354]here.[/link] Do a search for twin cat builds.
The rudder will go on the centre piece sticking our from the transom so you will need a centre mounted rudder like [link=https://www.mtc-powerboat.de/index.php?section=9&lang=en&produkt=15&detail=15]this.[/link] The standard ones on an L bracket will not work.