Hello,
      I have been away from this hobby for more than one year but it’s like ages for me. Now I am planning to build very standard 40 -42" catamaran with twin setup. I have already got the plans for the boat. Planning to build it December (Thanks to work from option). So it’s time to go shopping. It’s a big project for me so before spending on any thing I want to confirm the setup with experts. Here is basic Spec

1) Twin Glow .46 ASP marine engine (affordable and spares are readily available)/ other option is to get single marine Gas engine Zenoah stock 26cc. (Need Suggestion)
2) Centrifugal clutch (have found some for boat but first will check if I can get some car clutch)
3) Hardware mostly from HK (many has to hand made for this size of boat)

As this is my first project with IC engines I will be very cautious while buying hardware. SB sir need your  suggestion.

Seem very interesting & challenging. What materials are you planning to build from?

Will be following this with interest 

Will use 2mm ply and balsa. Later thin fiberglass epoxy coat.
This is going to be a long post. I ll start construction in December.
Now collecting info for getting hardware for boat. Most product i have selected are from HK and US, it will take some time to get here.

       If you can reduce the size upto 36 inch, electric is the best choice. But the performance and satisfaction of racing a 42 inch or higher speed boat is simply awesome.

       Contra rotating setup has its own merit; well balanced & very stable on water. For a 42 inch caterman, my guess 1.5 – 2 KW power i.e 2 x (1000 watt/ 2400 kv motors / 4S battery) will be more than sufficient, the cost for dual setup will be around 20k (for motor, ESC and battery).

       I don’t have much knowledge on marine gas powered engines, but I am not in favour of dual engine setups, instead of that a 26 cc single engine and dividing the transmission into two by messing two gears will be  much better (where equal power and rpm is achieved).

Amit,

    Last year I met a Salesman from Hi Power Engg. Company, and when enquired about small size petrol engines, he mentioned that their company is manufacturing petrol engines (30 – 35 cc) weighs about 1 kg, max. rpm- 10,000, inbuilt Clutch. The price is around 5k. The company is not selling products directly, but through Dealers.
    
     You can check these engines, mostly available at Agriculture Machines & equipment stores.

http://www.highpowerco.com/agri-div.html

Check out these plans.

Thanks Sb sir I have checked those engines from Highpowerco they will require some serious mod before we can use them, most important the coupling part. They would require gearbox as 10,000 is too low for direct use. These will be great if some one wants to use in big scale boat, won't give much speed like a big scale Yacht.  

One issue with using the Nitro engines is no contra-rotation, only if some one knows how to reverse the rotation of nitro engines. For this I ll use 3 blade propeller, adds stability.

Mounting them  will be another issue as silencer/muffler is on left side of engine so the engine which is on right side of boat will fit easily but it will be difficult for engine on left to fit as there will be no space for muffler on right side of left engine. For this problem one possible solution could be using flex-shaft and shifting the left side engine towards center to make space for muffler.

Next problem will be tuning them and making them have same RPM and sing the same tune    

These are the issues I have got in mind.

Electric for 42" will be more costly  :Rs:25000-30000 (Battery ESC Motor) will require 700-1000KV motor of size at least 40mm plus at least 6S lipo.
+++ all the hardware. Surprise to see that Electric for this size is more costlier than Nitro Setup.

Checked on Ebay got one 26cc gas engine for $155 + $55 shipping this will require clutch as idle RPM is quite high(Boat has to be hand launched)
clutch will cost another $50 + $15 shipping so this will go around $275 just for engine. +++ hardware

so made list(all HK) which is in budget but before going ahead need to think the solution for above problem or else have to reduce the size of model.

Friends need help on engine part as I am new to Nitro.

Thanks in advance.  

You seem to be working around an aircraft nitro engine. Suggest you look at a water cooled option only for boats.

http://www.mecoa.com/kb/marine/marine_inboard.htm

Ooops...sorry. I just saw the ASP Marine in the HK list 

Hello,

I have ordered some drive hardware here are the Buddy Codes for that if any one wants to buy them
all hardware is for 4mm drive system.

Ordered on 24/10/2013 valid for 14days

Shaft Adapter - 5mm motor shaft to 4mm Flexi Shaft
http://www.hobbyking.com/buddy.asp?code=B6D713C4-837B-4209-94CD-40B6B9FCFC24

Drive shaft with thread
http://www.hobbyking.com/buddy.asp?code=D191EA62-B6E0-46A0-818D-4F8329AA8D32

4mm Drive dog
http://www.hobbyking.com/buddy.asp?code=5837E6E5-EBBE-4F6D-863D-D438C1678ECB

4mm x 300mm Flexible axle
http://www.hobbyking.com/buddy.asp?code=AD3A39F0-6D89-4366-8FC5-4D5433537CC3

Glass Fiber Cloth 450x1000mm 18g/m2 (Super Thin)
http://www.hobbyking.com/buddy.asp?code=CA4D7961-428B-46BC-A135-C8065ADA3652

Canopy Lock / Latch Spring Loaded Twin Pack
http://www.hobbyking.com/buddy.asp?code=92DF82C4-9676-477D-9F4A-4CBAE116DC0D

Will order Engines in different order (Yet to deside electric or Nitro )

Amit

After month long study on nitro engines (On Paper) I came with conclusion.

1) Nitro is complex and twin nitro = (complex)³.  Tuning them will be a pain.
2) No contra rotating prop as no feasible way to run them in reverse. changing the shaft, piston and timing..... that's all we will stop there. That's too much for me.
3) .46 is a bad idea. Bigger the engine bigger the torque roll, no counter rotating it will take some rudder to run straight. I don't want that. Ideally .36 are the max size for any nitro application on the boats. these are not my views, views of those who tried and failed. I cant as failure is not an option with money involved.
4) Vibrations will rip the boat. And .46 will sure require FG or CF construction.

So Ultimately coming back to the point SB sir made, "36" with electric".(See,Experience talks here).

Still going to be twin (obsessed with it) electric motor.
turningy 3656 2000KV with 100 Amps ESC  running on 14.8 4S 4000mAh
4mm drive hardware.
prop:- I will start with X435.  Any Idea where to get Counter rotating Prop in India 

Does RCB Bangalore keep prop, I am going to visit them next to weekend for some balsa sheets.

Any suggestion on whether Balsa or FG
Points to consider not much time just get 2 weeks but full time.
for 36" will balsa hold good.


Will start construction from 22 Dec. Will post some pictures of the hardware I got today.

Goold luck for your build sir will be following it

RC Bazaar doesn't sell boat props. RC Dhamaka has a few-- http://www.rcdhamaka.com/index.php?main_page=index&cPath=65&zenid=tr1n640s2phgo4ba2155bic361

You can get FG cloth from Vijaya Traders, JC Road, Bangalore.

You can also get the props from hobbyking but you know then shipping charge, customs so it will be good to buy from LHS .

A member has already built a 42" V-hull with electric setup, looks pretty fast with a single motor drive-- http://www.rcindia.org/boats/my-new-42'-scratch-built-rc-boat/

Why not an electric twin drive for a 42" Cat?

Aman, unless the props are made of weapons-grade Uranium, customs won't bother.   

Haha weapons grade uranium

@Aman  Thanks, Checked Hobbyking but they only have 50 mm Counter rotating Prop. Those prop for 3656 size motor = Fire 100% Got many prop with me, just looking for set of counter rotating prop x435/x635.

Tower hobby has some prop but they need balancing and sharpening. that ads to cost and time.

@Anjan I have check the link you have  provided thanks for that  . RCD most prop are out of stock and there are no counter rotating prop.

These days HK parcel are not causing any issue, got my parcel in just 17 days and ordered for my friend he got it in 22 days.

It seems that idea for counter rotating prop need to be dropped.
I think it wont cause any torque roll issue as the prop will be small but RPM range will be higher,

Any suggestion on complete FG hull from mold or FG covering on a balsa hull.

Thanks,
Amit

Or Smith and Wesson used by Chuck Norris to make a black hole. 

im trying to find boat hull plans like the ones you got can you please help

Hi, any possibility to get this plans? Thanks.

Hello again everyone, its been 11 years since I started this thread. Today I have an update on the project.

First I dropped the plan to build this model from balsa, did not had that luxury of time so switched to 3D printing. I acquired the plans for 3d printing made my own modification (minor ones) and printed the model in parts.

Assembly was tedious, finishing was more. This is still not complete but I think with current progress, I will not be ashamed of writing this post after 11 years.

Some pictures and videos, Now model has too much power and as you throttle up, it tends to rotate towards the torque, my take I do not have the counter rotating props thus torque roll, but if you guys observe something, I will be glad to check it out.

PS:- Any pointers where to get the Counter rotating Props. Offshore electronics site is not reasonably priced site, $24 for one prop

few more photos

I did upload the plan in this thread, but its been long back so I might be wrong, Let me know if you still need them will send it across.

here is the short video  need counter rotating props, Any leads?

Hello, I can help you.
What is the prop size you are using?
How have you set the struts? Is there any angle?
Have you check the CG of the hull including battery?

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