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Author Topic: My First Boat!  (Read 8100 times)

Johnathan

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My First Boat!
« on: July 27, 2007, 07:58:58 pm »

Firstly  -  hello, this is my first post. I'm Johnathan, i live on Anglesey in North Wales.

Although I am not new to RC (I fly planes and helis), this is my first boat and I am not familiar with some of the hardware. I'm going to list what I'm building, what hardware I already have and how I intend to use it all, so hopefully I will get some replies saying I'm either doing it all wrong or I am in fact on the correct path.


Okay so I live on an Island! We do have a boat club near but from what I can see on their website, their lake would not respond to my boat well and that would only be if they would be happy about me using an I/C engine to power it. So its saltwater for me. We have a few bays and on good days they can be very quiet and calm.

I have a good idea of what i need to get the boat running, but some of the bits i need clarity on.

Problems at this moment are:

1) I have no idea what couplings to use to connect the engine to the prop shaft .. I think this --> Click Here
2) Where do i position the engine mount.. More forward, more towards the back or in the center?
3) Water cooling i think i will be using some brake line round the head. the rudder has a pickup and i have somewhere for it to leave the boat.
4) Radio gear.. making it water tight?
5) Servos for throttle and rudder - do they need to be waterproofed?
6) How do i fit and make sure water does not enter in through the prop shaft?
7) if its surface drive, does that mean the prop has to leave the stern flat .. or can it be at a slight angle .. due to the engines mounting

I appologise if they seem obvious to you .. but its doing my head in :)


Parts are:
Boat Hull - Mono V hull (i think thats what its called) Fibreglass 32" long / 8" wide
Engine Type - 0.40 OS MAX Plane engine (I'll need to make my own cooling)
Engine Mount - .40 - .60 Anti Vibration
Drive Type - Surface
Rudder Type - 150mm Wedge rudder with water pickup
Prop Shaft - 15" Saltwater Propeller
Propeller Type - Alloy prop to suit .40 engine
Turn Fins - Alloy CNC machined
Trim Tabs - 4 instead of normal 2
Radio Gear - Futuba 4 channel

* I am aware of the post somewhere else about plane engine RPM's and torque etc. This engine will do for me right now to get the boat going as i have it already. I also have a .60 and .90 engine in a Biplane i could use should i need to. Or I'll just get a marine engine. Either way .. please please don't focus on the engine! :)

Rough engine specs
Engine Type:    2-Stroke
Displacement:    .400 cu. in.
Cylinders:    1
General Specs:
- 1 cylinder
- Displacement: .400 cubic inches
- Bore: .807 (in.)
- Stroke In: .768 (in.)
- Shaft: 6-32
- Low RPM: 2800
- High RPM: 17000
- 1.200 bhp
- Weight (no muffler): 13.90 oz.

Few pics of parts - more to come when i start to build this in a very short while (when all the bits arrive.)


Hull Bottom


Engine Mount






Wedge Rudder with water pickup for cooling


Saltwater Prop shaft


Propeller


Turn Fins - help with turning on fast boats






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glennb2006

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Re: My First Boat!
« Reply #1 on: July 27, 2007, 09:26:09 pm »

First - welcome. Prepare for an addiction to speed and water!

Drive: You have two choices really, and you need to decide before building which route you are taking.

1. Surface drive - used on offshore boats often, the prop actually runs half in and half out of the water.
2. Submerged drive - the prop runs on a shaft (like yours) beneath the boat.

Surface drive is generally regarded as being faster, submerged provides a boat that is more manouverable. Generally.

3. Cooling - in the dim and distant past I have managed to get some copper wrapped around the cylinder of an aero engine. It worked fairly well. To be successful, find something a little less diameter than your engine. (Like a battery maybe, or some steel pipe - whatever). Seal one end of the copper tube. Then- fill it with salt. Honest. When filled, seal the other open end. Bend the pipe gently around your former. The salt stops the pipe collapsing. Silver sand is the age old stuff to fill the tube with - bet you have none, but can almost guarantee you have granular salt in the house. 
When complete - cut the ends and get your salt out. This takes more time than bending it! Then it should be a snug fit onto the cylinder and a jubilee clip should hold it snug in place. Might be able to run some on the pipe as well if you want.

4. Fit the radio gear into a box inside the hull, typically people use electical boxes, they have seals on the top or you can buy proprietry radio boxes. Can't see inside your hull, but you might be able to build a radio compartment into the rear of the boat.

5. The servos need to go into the box you fit above. If not they will fail.

6. The shaft you have will not take water on, the drive end of it will be above or close to water line. Flexible shafts used on surface drives do take some water on, but not when the boat is moving. Keep it moving!!

7. Surface drive, as touched on, the drive shaft is flexible and comes out of the transom of the boat at the "point" of the vee. Roughly. Then the drive strut etc is bolted through doublers onto the transom. As does the rudder. Unless you go with submerged drive where the rudder is also under the boat and in the prop wash. That is why they turn quicker.

8. Couplings are pretty much down to preference. I use the polish type on my sub surface drive boat "http://www.czarnecki.pl/fsr/index.htm" the coupling is 14 items down the page. It's personal preference and the stuff sold by Dave Marles is all very good quality. And works.

9. Your engine position is going to be determined by prop shaft length if you stay with submerged drive on this one. The boat destructions should detail where the prop and rudder need to be, then naturally the engine is going to be that much further forward than the screw.

I can give you some copper pipe to wrap round your engine as a cooling coil if you want to PM me an address.

A couple of other things to bear in mind early:

Need some flotation in the boat for when it turns over.
Everything is going to need to be well washed off and protected on completion  of running in salt water.


Come back for more advice as often as you need, will try to help where I can as will the other guys. Out of interest, do you have a name for the hull. (IE mirage or anything similar?)

Glenn
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glennb2006

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Re: My First Boat!
« Reply #2 on: July 27, 2007, 09:34:50 pm »

Also, you are going to have to get a flywheel from somewhere for your engine too.
Look at the posting Shockwave 55, 2 down from this one, there are photo's amongst that that show pretty well the surface drive arrangements.

Glenn
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Johnathan

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Re: My First Boat!
« Reply #3 on: July 27, 2007, 10:06:17 pm »

Hi thanks for the reply .. :)


No I don't know what model the hull is sorry, i have had it sent to me by a chap who is developing it. Once i know where all the parts are going to be fitted i will be sending measurements for him to make the deck. Its that fresh.

I have seen the flexible drives and realised after i submitted the post that for surface drive, its probably what i would need. My idea and reason for the question about the drive coming out the back of the boat at an angle was...

.. if i drill a hole in the bottom of the V at the back and fit the propshaft in there, to be a real surface drive that would mean i would have to have it running straight and flat along the bottom of the hull right? But mine will have to be at an angle to attach it to the nitro engine on that engine mount, so that would then make the prop shaft and subsequent propeller point slightly downwards. The rudder will still be at a level where it will be in line with the prop though, so will i be able to do it that way? I mean it will point at an angle, but only by a few degrees.

I mean its like using a surface drive setup, except with the prop at a slight angle as if the shaft was exiting underneath the boat. I really want to make use of the shaft now i bought it .. haha.. I will have trim tabs and turn fins so that should help me set the boat up?

Is 1.2hp .40 engine going to do for this boat or should i start preparing for the bigger engines now?

Would i need a flywheel if i had a pull start?



Again sorry if all this sounds stupid, i have never even had a boat near, never mind in the water before :D



 
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Johnathan

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Re: My First Boat!
« Reply #4 on: July 27, 2007, 10:07:28 pm »

Oh .. and that shockwave 55 is an exceptional boat!



Johnathan
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glennb2006

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Re: My First Boat!
« Reply #5 on: July 28, 2007, 01:23:11 am »

Hi Jonathan,

bad news I'm afraid; if you are going to use that shaft the only way you can do it is to use it as submerged drive. Which your engine mounts lend themselves to. But your rudder does not.

So, if you are going surface drive, your engine mounts should be OK, the rudder is fine, but you will need a strut and flex shaft, and shaft tube to go with it. Money wise it's probably the best option for you. Sell the shaft you have on ebay or keep it for when you build an FSRV boat.

Is that hull in the photo the one your friend made you? Also, I assume you have all the parts in the pictures?

If your shaft is angled down too far, which if you used the one you have as a surface drive would be the case, the thrust from the prop would be such that the nose of the boat would continuously be being pushed into the water. I very much doubt the boat would plane.
If you do go submerged drive - the one thing I can pass on as a suggestion is to try to get the shaft mounted at as shallow an angle as is possible, and make sure it is straight too.  ;)
And in line as best as you can get it with your engine. You want as little misalignment as possible between shaft and crankshaft, it just saps power, causes vibration and wear. :(
The rudder assembly you have is designed to be mounted to one side (usually stbd) of the centre line of the boat. Not in line with the prop.

I should think that with a happy little .40 and a tuned pipe that boat should pop along OK, provided you build it nice and streamlined.

Remember that everything that goes into the water creates drag, and drag slows you down.  >:(

If your friend who created the hull is an experienced boater, which looking at the hull he probably is, he will be able to recommend CoG points and drive configurations for you.


Glenn

 

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Johnathan

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Re: My First Boat!
« Reply #6 on: July 28, 2007, 02:11:31 am »

Okay great thanks.

The hull was designed for surface drive, so i had better go with that. It was my error buying the saltwater propshsaft then. I will work out the CoG and then get the correct length flexishaft and strut to support it.

Yeah the hull in the pic is the one i am going to use. I will take better pictures tomorrow.

So i need..

Flexshaft
Shaft Tube
Couplings for Flexshaft
Strut for Frexishaft

And maybe a different propeller if i use a .60 engine later on.


I got my gear from Dave Marles on ebay so i will just go back there for the gear! If anyone has (by chance) the correct item numbers i should be buying, i would appreciate that!


/Johnathan


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glennb2006

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Re: My First Boat!
« Reply #7 on: July 28, 2007, 02:59:53 am »


Have a look here Jonathan:

http://www.prestwich.ndirect.co.uk/surfacedrive.htm

I think if you speak with Dave you will find that you should be able to get away with a 3/16" shaft for the 0.40 motor. I was looking HF2. Might want a bit longer if your motor needs to go forwards.

To balance the boat, mount loosely all the bigger lumps, motor, tank, pipe strut etc, some tape into position to make it as accurate as possible, then shuffle the motor forward and aft to get CoG where the boat maker says it should be. Rule of thumb if the maker does not tell you where CoG needs to be is 25% to 30% forward of transom. Balance the boat over a broom shank to find where it's CoG is.
Here are some possibles for surface piercing props., ask Dave when you speak to him if he can get them and what size the boss on them is. (To ensure you get the right shaft installed) These prop sizes are recommendations for 7.5cc motors, so thats you. Might be a bit much for your motor but start small and see how it goes.

 
X450/3, X452/3 X455, X457, X646/3


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Johnathan

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Re: My First Boat!
« Reply #8 on: July 28, 2007, 04:04:13 pm »

Hi

yeah all those parts are parts i have ordered through ebay from PMB Model Boats and apart from the Rudder (which is in transit), i have all the stuff i listed.


I have just contacted Dave again to see if he can have a look at the info i have laid down and suggest the best course of action. Infact while writing this he has written and said these parts will be what i need .. HF2 flexi shaft assembly, HF19 coupling 1/4 unf thread. Propeller would be X447.


Best get them sorted out soon then.

Also, thanks for the advice on setting it up. As soon as i am sure i have the right parts i will crack on and follow all the bits that have been posted. please if anyone feels there is something else a new boat builder (especially a nitro boat) should know, feel free to tell me :)

Whats the best fuel?
Can i get a tuned pipe to fit my engine? (Irvine .40)
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glennb2006

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Re: My First Boat!
« Reply #9 on: July 28, 2007, 06:45:51 pm »

You sure can get a pipe, look here.

http://justengines.co.uk/

Speak to the lovely just engines people and they will get something sorted for you quicker than a quick thing.

As for fuel, as you have run this engine before in a plane I would use the same fuel as always, probably 5-10% Nitro with plenty of oil should keep you going.

It will be nice to see progress on the build as it goes on, photo's are always good.

All the best,

Glenn

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omra85

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Re: My First Boat!
« Reply #10 on: July 28, 2007, 09:35:40 pm »

Hi Johnathan and welcome to the crazy world of IC boats.
Glenn, as usual, has been giving you good information.
I have been racing nitro boats all round the UK (never North Wales though) ???  for more years than I care to remember.
The OS40 will go fine in that hull.  I'm in the process of building a 48" hull with a Picco 67 in it.
The engine in the photos is not yours, right?  Is yours side or rear exhaust?  The reason I ask is that - if it is a side exhaust it will be less powerful, but, more importantly, will require a different fuel tank and manifold to a rear exhaust model.
I'll try to get some pics of mine tomorrow (and more as I build it) which may help you.
Cheers and good luck
Danny

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Johnathan

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Re: My First Boat!
« Reply #11 on: July 29, 2007, 02:07:03 am »

Thanks for the interesting replies guys..

OKay so rather prematurely i have decided to fit a 10cc engine from one of my planes into this boat. I think that will give it enough 'oooomph' to keep me interested for a fair bit. The engine is an Irvine .61 with a side exit exhaust as per most plane engines. Once its in i will have no choice other than some sort of custom pipe, as the side exit one with the engine is far too big and bulky!

I will be getting these parts from Mr Marles as soon as i can.

HF2 Surface Drive flexi shaft assembly
HF19 Coupling
X455 Propeller + Balance and Sharpen
     


That lot should get me onto something that looks like it just needs some electrics in. I'm looking forward to getting this done and on the water! Glenn's advice does seem spot on, and yeah i would love to see pics of your boat build too.

I am also interested in seeing an videos of boats of a similar size and engine size to mine.

/Johnathan
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supersonic

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Re: My First Boat!
« Reply #12 on: July 29, 2007, 10:50:42 pm »

Hi Jonathan,welcome to the forum.
Have a look at HUNTSMAN BUILD under Sorts, Pleasure craft, etc.This may be of interest to you
The boat is a fairey huntsman 31. 34inch long fitted with a LEO 46 (No tuned pipe yet )
Still running in, and getting used to  the handling.

dave
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glennb2006

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Re: My First Boat!
« Reply #13 on: July 30, 2007, 01:36:45 am »

Careful mind - that's how I started, an innocuous little wooden boat passed to me out of a loft hatch by my Father.

Complete, in my case, with a box containing an "ED" diesel motor.

G
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glennb2006

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Re: My First Boat!
« Reply #14 on: August 11, 2007, 01:53:01 am »

Hi Jonathan,

how goes the project for the boat just now? Still plodding on I trust.

Look forward to reading more on your progress with it.

Glenn
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Johnathan

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Re: My First Boat!
« Reply #15 on: August 13, 2007, 02:01:32 pm »

Hi

Yeah i am just awaiting the flexi drive parts and a balanced and sharpened x455 prop


once they arrive i will be blagging your heads for information again on how to set it all up :)


I'm really looking forward to it


Johnathan
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BJ

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Re: My First Boat!
« Reply #16 on: August 13, 2007, 02:12:09 pm »

It is not expensive to buy a marine head for an SC engine.
Picture shows Just Engines Purple range tuned pipe prior to water cooled version fitted & Leo 21 engine
Picture 2 shows three pipes being converted using slow cure JB Weld to secure jackets.
Radio box has Film Can section to access Rx charge socket
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Johnathan

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Re: My First Boat!
« Reply #17 on: August 13, 2007, 06:41:54 pm »

Thanks for the pictures, they look interesting.


Will i need a flywheel to start this thing then, or can i do it another way?
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glennb2006

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Re: My First Boat!
« Reply #18 on: August 13, 2007, 08:08:24 pm »

Hello again Jonathan. Flywheel will be required yes. And a belt to go around it to start it, I assume you have a decent starter from your plane.

Glenn
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Johnathan

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Re: My First Boat!
« Reply #19 on: August 13, 2007, 09:13:25 pm »

Yeah i have a good starter i use for the planes/helis


I was not liking the flywheel idea because obviously the belt has to stay on while the boat is running - then again a load of you guys use that system? I was thinking of making some sort of tool which would attach to the starter and then just slot over the prop and turn the engine that way.

does anyone do this or does it cause damage to the prop?
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Marks Model Bits

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Re: My First Boat!
« Reply #20 on: August 13, 2007, 09:26:31 pm »

Hi and welcome to the forum.
I am no expert regarding I.C. boats but trying to start the engine using a modified starter on the prop would damage the flexi shaft and it would (possibly) unscrew the lock nut on the dog drive as well  as it will be turning anti clockwise.

Mark.
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glennb2006

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Re: My First Boat!
« Reply #21 on: August 13, 2007, 11:52:13 pm »

Hi again,

No mustang at the moment mark is correct the flexi will not be able to take the lumpy starting torque (And it will try to unwind too). Also the prop would almost certainly be damaged. Chances are the coupling will not be able to transmit the torque without loosing grip on the flex cable.
There is no problem using belts, they just stay happily in place in the bottom of the boat once the engine is running.

Thinking on, it might be easier for you to buy a second hand marine motor if you can find one, flywheel etc will be there and you might even score for an exhaust system if you are lucky. Just a thought.

There was a fella on here advertising in the sales section a load of engines from a deceased relative, think there were some brand new unused Merco's there.

Glenn

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BJ

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Re: My First Boat!
« Reply #22 on: August 14, 2007, 08:16:42 pm »

Thanks for the pictures, they look interesting.


Will i need a flywheel to start this thing then, or can i do it another way?
The BRASS piece in the picture is the flywheel and the belt in the picture is the Polyurethane type of Vee belt. A "Black rubber or neoprene" belt is better than the "poly" type in my opinion.
Look for the guy selling vacuum cleaner parts on a local market for a suitable belt or the local transmission parts supplier before trying the model trade and their mark up - about £3 seems average for a belt.
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Johnathan

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Re: My First Boat!
« Reply #23 on: September 28, 2007, 12:33:48 pm »

Just a quick update.

I'm still waiting for the parts i ordered from Dave Marles. Is there anyone who can give me the phone number as i am now seeking a refund so i may get the parts elsewhere. He is not answering emails at all.

I'm sure there is a good reason.



Johnathan
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glennb2006

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Re: My First Boat!
« Reply #24 on: September 28, 2007, 12:45:22 pm »

Hi Jonathon,

http://www.prestwich.ndirect.co.uk/

Latest number is 07842 634090.

The old number, not sure if it still works is 01942 719147.

I know Dave has been abroad for a few weeks racing, so maybe that's why he has not been in touch. You can contact him on email through his web site.

Regards,

Glenn
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