Paddleducks

Paddler Modelling => Construction => Topic started by: derekwarner_decoy on February 24, 2008, 12:13:09 AM

Title: Stability
Post by: derekwarner_decoy on February 24, 2008, 12:13:09 AM
Hi PD's...I know we have touched on vessel stability in or under different threads...but when reading...'Clyde River Steamers of the past 50 Years' circa 1923 [prior to ISBN].....found this listing of Eagle III ....as listing some 14.222 degrees to STDB  :sorry :oops
Title: Re: Stability
Post by: Tug--Kenny on March 21, 2008, 07:23:02 AM

That doesn't look good.

Is this a problem with flat bottomed boats?

Ken
Title: Re: Stability
Post by: derekwarner_decoy on March 21, 2008, 11:12:54 AM
Hi PD's....Ken, the text states that the Eagle III was built by Napier & Miller @ Old Kilpatrick...but the designer  :shoot  is not acknowledged

......"Unfortunately, this boat proved deficient in stability, so it was shortly found necessary to withdraw her in order to have  :hammer alterations made on her underbody"

...again the text notes that these modifications were successful as she served in the Nort Sea in mine sweeping duties


...So to answer your question.... "is this a problem with flat bottomed boats?"....well yes & no...naturally must depend on the metrecentric point of balance   :ranting..so if you can build & get the all heavy bits down low :crash :crash :crash you will not experience a list [typical of a  :beer]............ as the Eagle III [as built] suffered
Title: Re: Stability
Post by: Tug--Kenny on March 22, 2008, 07:40:27 AM

Thank you for that. I noticed most are flat bottomed. I wondered why this was.

I shall ensure all the weight is kept as low as possible then.

As an extra question, I was thinking of where the paddle shafts came out of the sides. Is there a formula or consideration with the water level regarding height above, please. (thinking of leek's or paddle strength and depth)

Hope you can help,

Ken
Title: Re: Stability
Post by: Eddy Matthews on March 22, 2008, 08:15:26 AM
Stability is an issue you need to take seriously with a paddler Ken - Remember, unlike a screw driven vessel, you have a paddleshaft relatively high up in the hull - The paddlewheels, paddleboxes and sponsons hanging off either side of the hull, and then the superstructure up top.....

As Derek said, keep all the working parts as low as possible in the hull, but also keep the weight of the superstructure and paddleboxes/wheels as light as you can - Think about it constantly during the build, and if you can save weight DO SO!!

I speak from bitter experience with my first paddler - A model of the Director class paddletug "Forceful". I spent over 18 months building it and made all the areas mentioned above far too heavy! Result was a boat that always wanted to try and roll over, or at the very least it would run with an alarming list!!

So if you only take away one piece of advice from Paddleducks - SAVE WEIGHT has to be it!

Title: Re: Stability
Post by: derekwarner_decoy on March 22, 2008, 08:32:54 AM
Hi PD's...the other point for consideration Ken is to BUILD from a plan...... be it a commercially available plan or true vessel dimensions that you can carefully & accurately scale  :hammer
Title: Re: Stability
Post by: Tug--Kenny on March 22, 2008, 09:36:49 AM

Thank you all for the information. I shall certainly be building from a plan. After all, these paddlers have been around a long time, so their experience and know how is to be appreciated.

I just spent a few hours browsing around PaddleDucks and am learning an awful lot of things which is going to help me in my latest build. What a little treasure you have here.  8)

Must go now as my eyes are drooping.

Ken
 
Title: Re: Stability
Post by: derekwarner_decoy on March 22, 2008, 02:46:34 PM
Oh dear PD's  :shhh......quote from Ken (thinking of leek's or paddle strength and depth)

 :nono...I thought a LEEK was some sort of British vegeitabilbieell  :hehe

So Ken.....it is  :terrific to see that a new member is going back & researching the files  :crash :breakcomp :coffee :crash :breakcomp

You will find a number of references on paddle shafts/axis/keeping the water out/ = no LEAKS ...

Also your admission of being an EX keyboard engineer will keep you in good steed/stead with some of our senior members who also had a previous  :whistle life ...but enough of that for now


Title: Re: Stability
Post by: Tug--Kenny on March 22, 2008, 11:42:27 PM

Well here we are back all bushy tailed and not leeking. :D

My reason for keeping the the Wet stuff out is because I'm a sinker of the small craft.  I had the misfortune to Not secure a Hatch cover before setting sail in a raining, gusty day.

She didn't take to fast cornering to get back to the bank in a storm and correspondingly went to the bottom. It's all on You-Tube if you've got a half hour to spare. It's the complete step by step build, Warts and all. This is part two, the movie.

http://ca.youtube.com/watch?v=82ruSFLuInw

Here's hoping to keep Waverley above the waves...

Cheers...ken