Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Working Vessels => Topic started by: polaris on November 04, 2008, 07:01:46 pm

Title: Sternwheel River Boats
Post by: polaris on November 04, 2008, 07:01:46 pm

Dear All,

A thought crossed my mind the other week, and I write in case someone can answer the following question.

How is a sternwheeler river boat steered???! Forward and reverse control is obvious, but how does one maneuver the thing!

There obviously must be a rudder somewhere... but where on the hull? - or nearer the Bow?

Regards, Bernard

Title: Re: Sternwheel River Boats
Post by: RickF on November 04, 2008, 07:16:57 pm
Bernard,

Here is one of the twin rudders on a Yarrow-built Nile gunboat.

Rick
Title: Re: Sternwheel River Boats
Post by: Colin Bishop on November 04, 2008, 07:32:22 pm
Many of them had long shallow rudders projecting out behind the paddlewheel. I think some also had a combination of rudders forward and aft of the wheel. At least one sternwheeler had a split paddlewheel with both sections independently operated.
Title: Re: Sternwheel River Boats
Post by: towboatjoe on November 05, 2008, 12:22:09 am
Colin is right. The main steering rudders on a sternwheeler is located forward of the wheel. Some have two most have three. Later they added rudders after the wheel called monkey ridders because they are fixed in tandem with the steering rudders and mimic their movement. I guess they named them that from the old saying "monkey see monkey do."

Here are a couple photos of the George M Verity and some pics of my model. You can see my monkey rudders are chain driven just like the prototype. Other photos show how I joined the monkey rudders with the steering rudders with one servo for steering.
Title: Re: Sternwheel River Boats
Post by: FishdockBob on November 05, 2008, 12:50:10 am
I really like that bottom pic of your sternwheeler towboatjoe, looks very atmospheric on the water  :-)
Title: Re: Sternwheel River Boats
Post by: Garabaldy on November 05, 2008, 01:02:36 am
thats an impressive looking linkage!  Although i dont really follow exactly how it works.  Do you need a servo with more torque to operate the 3 rudders?

G
Title: Re: Sternwheel River Boats
Post by: PT Sideshow on November 05, 2008, 10:50:15 am
 :-)) very nicely done
Title: Re: Sternwheel River Boats
Post by: towboatjoe on November 05, 2008, 12:30:18 pm
thats an impressive looking linkage!  Although i dont really follow exactly how it works.  Do you need a servo with more torque to operate the 3 rudders?

G

A standard servo worked fine. There are six rudders altogether. I just coupled the three steering rudders together and made a tiller arm on the port rudder. There's a connecting rod that runs from the tiller arm up through the servo arm and bends on the end for connecting the chain that works the monkey rudders. After getting all the rudders in alignment I secured the chain on the connecting rod and used a spring to hold tension in the chain. The trick to having a strong chain is to find chain with soldered links.
Title: Re: Sternwheel River Boats
Post by: Martin (Admin) on November 05, 2008, 04:34:25 pm

Hi Joe, What's the reasoning behind the "Vee" shaped paddles?
Title: Re: Sternwheel River Boats
Post by: barriew on November 05, 2008, 05:06:35 pm
I have built Lulonga without a rudder at the moment as I have independent control of the two paddle wheels. According to the designer of the model, a rudder is not required - we'll see ok2

However, this is not a scale model, so don't know what this type of vessel, African River boat, would have had.

Barrie
Title: Re: Sternwheel River Boats
Post by: polaris on November 05, 2008, 07:20:58 pm

Dear All,

Thankyou for explaining how they are steered. I am pleased others have found this thread interesting as well - glad I asked the question and put the Thread up!

Regards, Bernard
Title: Re: Sternwheel River Boats
Post by: towboatjoe on November 05, 2008, 11:26:43 pm

Hi Joe, What's the reasoning behind the "Vee" shaped paddles?

It's called a helical wheel. ARMCO had two boats with this design. The idea was to lessen vibration throughout the hull of the boat. Flat paddles smack against the water much like when you take you hand and hit the water. It transmits that shock wave throughout the hull and the helical wheel smacks the water at an angle and causes less shock vibration. It worked somewhat, but not well enough to out weight the cost of making and repairing the helical wheel.