Building a new boat {OK dreaming about it!!]

[Wearyman]

You know, it occurs to me (and I can't believe I didn't think of this before) that you could simply add a crank to the end of the prop shaft, tie it to the engine with a pushrod and a second crank and have done with it. At least, I would think it would work, although I don't know if it's done all that much.

Normally you would use a crank to turn vertical motion into rotational motion, as the engine does. But could it be used to simply transfer existing rotational motion to a new, parallel line? The image below illustrates this in a side-by-side configuration, but it would be easy enough to to an over-under arrangement too.




Theoretically it seems sound, although the double-CV/double Universal joint sounds like it would be easier. It's an idea anyway.

[mcandrew1894]

Farmerden,

Dave That's an interesting set-up for the sight glass and the three drains in the boiler. Do you have a better photo of it? I've always wanted to have something like that up front so I wouldn't be stuck back with the engine all the time.I think something like the might do the trick. Do you think the captain might even let the engineer steer the boat? Den

If you look at the pictures in the links, its a water column. Those are trycocks, but I think you knew that. As you can see, the column is turned and faces the engineers position on the starboard side...by the wheel..as well as all the other controls.


Sorry for the highjack...please proceed....
Dave


http://i164.photobucket.com/albums/u27/ ... 010010.jpg

http://i164.photobucket.com/albums/u27/ ... 010008.jpg

http://i164.photobucket.com/albums/u27/ ... 010007.jpg

[87gn@tahoe]

How is the stability of the water in the glass?

I would think that being uninsulated, your column would act as a downcomer of sorts.

[mcandrew1894]

It does a bit. I am in the process of insulating the pipes, now that the layout has somewhat solidified.

As long as my feed is hot, the level is pretty stable. If I pump cold water in with the hand pump....the level will drop right out of sight. Swell and shrink....but that has to be expected with this boiler....I think the water level is more stable with the water column than without it.


Dave

[farmerden]

Trycocks-I knew that! It's just now it seems if someone says "Hello" I'm stuck for an answer!! Must be my age!! And Wearyman Your drawing would work just fine cept you flat out do not have spare horsepower to run it! I have an alternator run by a fanbelt which I just roll on the belt by hand whenever I need it. I betcha I lose half my power! So running thru transmissons or crankshafts would use too much power. I wonder how much loss of power occurs in a chain and sprockets[belt and pulleys]? Den

[mcandrew1894]

Timing belts are in the 90% range as far as power transmission efficiency. I think chains are right behind them. Maintaining the tension adjustment on a timing belt is far easier and it doesn't require lubrication....but gears use a lot of energy in most applications....comparitively speaking.

My vote...if I was to go that way...would be for the timing belt......FWIW.

Dave

[froya66]

On Frøya I also make use of a timing belt with a jockey wheel on the slack side, propeller RPM is 2 times the engine RPM. (300 and 600 RPM)

I also found that effeciency is good, and that the whole set up is all right, but make sure that the wheels are of prober diameter.

If the diametres are too small, the belt will cam over when reversing unless the jockey wheel is pressed extremely hard against the belt. The bearings might not like that!

If you go for a "standard" propeller pitch, and use the belt for speeding up the propeller, it might be harder for the engine to overcome the dead centers when reversing.

Best regards
Froya66

[fredrosse]

My electric boat uses a toothed timing belt 4:1 ratio. Running 5 years now without any problems. Toothed belts are not too expensive, but the sprockets are fairly expensive.

The timing belt setup on a typical 4 cylinder car engine is most probably strong enough for a steam engine of a few horsepower, and 2:1 ratio. This setup, with sprockets, would be inexpensive if obtained at an automotive junkyard.

[PeteThePen1]

Dear Den and boating friends

Please keep going and lets see some photos of the chain/belt systems that you have all mentioned. I am planning to follow the same sort of idea that Den proposed, but not to quite such an extreme height. So, I am all agog to see how to do it.

On a related but "off topic" slant, Dave, what is the copper pipe that runs from the steering position to the fore locker and back along the other side of your boat. It looks to end in space or have I missed something? I am also pleased to see how you have rigged you hand pump. That answers the question I have not got around to asking.

Best wishes

Pete

[mcandrew1894]

Hi Pen,

Sorry for the delay....work is very busy these days.

I use the pipes on both sides to stow stuff. It works well with seat cushions, fire extinquishers, throw rings, ect. The one on the port side ends in space at the rear bench at about station 9. IIRC

The pipe on the Starboard side is also a feed line from the bow tank as well as from over board draw. It is plumbed to take feed water from either via the hand pump and/or the injector. So it does double duty.

The HAND pump hadn't gotten plumbed to the starboard side pipe yet in the photo above.

It has since.

Regards,

Dave