Model Boat Mayhem

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: Displacement tests....  (Read 5892 times)

benjaml1

  • Guest
Displacement tests....
« on: October 29, 2009, 12:25:35 am »

Wifey is at her mums, good time to work out ballast requirements.... 480 fluid ounces has her settling nicely. Yes, this is my winter steam project... :-)

What I shall do in the morning is put a few drops of oil based paint on the temporary "ballast" water ( inside) & that will leave me a datum. It's a Orion Moulding's Scottish Fifie, which is a little larger than I expected... :o

Logged

Bunkerbarge

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 2,570
  • Location: Halifax, UK
Re: Displacement tests....
« Reply #1 on: October 29, 2009, 06:44:10 am »

Just one thing to bear in mind with this method is that the hull will tend to find it's own attitude, which may well not be the attitude you want.  Differences in the fibreglass density and distribution as well as the shape of the hull form could well dictate that the hull does not sit at the required level and the water inside will not force it to, all that does is to produce a downwards force at the effective centre of gravity.  Just think if the hull is slightly heavier on one side what is to stop it heeling over  When you then mark it you will be working at a waterline on an angle.

You are really working the wrong way around.  You need to decide at what level you want the hull to sit then make a water line on the outside with pencil and follow that with some lining tape or masking tape.   If the hull is already marked with a recommended water line then use that or take it from the plan if you have one of those. Then you need to put the hull in the bath and add fixed weights to get the hull to sit exactly as you want.  Don't forget the distribution of your steam plant will also play a big part here so it's worth having the big bits to hand before you get too far down the line.  If it sits too low at the back you may then need to add more ballast at the front and if it heels over a couple of degrees you may want to add the ballast a little bit towards the other side.  I would definately not determine your water line from the method you describe because there may be a chance that it doesn't work out when you fit the plant. 

I would put the hull in the bath with the water line marked out, put your big steam plant bits in where you want to put them, such as boiler, engine, separator tank, gas tank, bateries, large resin figure etc..etc..  Hopefully by this stage the mode is still too high so you can then add more weights in the required spots to get it to the right level.  Then remove the plant pieces and weight the hull with your added ballast and weight it without to get the required amount of additional ballast.  Some of this could then be fixed in the bottom of the model, say 60-70%, and the remainder kept in hand for when it's finished and you can trim it perfectly with the last few bits and pieces of 'detail' that will make it sit exactly as you want it on the water.
Logged
"Dirty British coaster with a salt-caked smoke stack, Butting through the Channel in the mad March days"

Bernhard

  • Guest
Re: Displacement tests....
« Reply #2 on: October 29, 2009, 07:57:22 am »

hi..Great hull..i like it look like ,it whas old wood......what plant will you use in it,,,,,,,,,,

Bernhard
Logged

benjaml1

  • Guest
Re: Displacement tests....
« Reply #3 on: October 29, 2009, 09:19:44 am »

Thank you Bunkerbarge for your good advice. In reality I was just trying to work out roughly the amount of ballast I would need & got a little too clever for myself.. :embarrassed: Steam unit, I have quite decided yet, depends on what is available at a reasonable price ( oxymoron for a good steam engine I know.) I'm scouting e-bay USA/UK & Germany right now & have two Graham Industries TVR1A kits on the way that I will couple if I decide to use them. Not quite decided as yet as there are two Stuarts that take my eye... The boiler I shall make myself, vertical coffee pot is what I am thinking...but that depends on the bureaucracy required for testing/ certification. Haven't really read up on that as yet but I live a few miles from Cheddar so there are minds smarter on the subject than mine living very close... As I may have intimated in a previous post, I'm newly returned to these Isles & have a lot to learn about the changes...
Logged

gondolier88

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,347
  • www.coniston-regatta.co.uk
  • Location: Crake Valley, Cumbria
    • Coniston Regatta
Re: Displacement tests....
« Reply #4 on: October 29, 2009, 03:34:00 pm »

The hull looks very much like a ship's launch to me- double enders were commonly used as they could withstand continuous lifting out of the water and putting back in better than counter sterned ones- something to think about if you havn't thought exactly what to do yet.

There were many variants on the theme- though commonly none had cabins- most had vertical firetube boilers with small compound/ triple machinery, condensing.

A few boiler designs to have a look at (full size) would be- Kingdon Boiler, manufactured predominantly by Mssrs. Simpson & Strickland of Dartmouth. Also LIFU machinery would be a good point if you wanted to use a design from later in the steam period- these were watertube boilers.

You have a wonderful hull there, I look forward to seeing what you do with it.

I'm building the Stuart D10 at the mo' if that was one of the designs you were keen on it will be up for sale when it's completed.

Greg
Logged
Don't get heated...get steamed up!

benjaml1

  • Guest
Re: Displacement tests....
« Reply #5 on: October 29, 2009, 07:35:03 pm »

Thanks for that Greg, I have been scanning the internet for pictures & inspiration. I would like to build something that is close to realism....
Logged

geoff p

  • Guest
Re: Displacement tests....
« Reply #6 on: October 30, 2009, 06:06:44 pm »

I do believe Benjaml's hull is of a Fife, whereas Bernhard's model is more likely a ship's lifeboat.

Many years ago when we lived in Shetland, I bought a Fife as a derelict on the beach: "Girl Anne" was 21 feet LOA by about six or seven feet beam.  The stem and the stern were very straight and had very little rake from vertical.  Her planking was larch-on-oak, the planks about 5" x 1/2", lapped (clinker-built) and copper-rivetted with the occasional blooming big iron nail through a frame.  The rivets were at about 6-inch spacing, which left space to add an extra if the boards sprang a little, and the sawn frames were probably 18" to 2 feet apart.  Contrast that with Bernhard's hull - rivets at about every two inches.

(As an aside, we hauled her back to our house and spend many, many hours trying to re-plank her:  even at only 1/2 inch thick, the larch really needed steaming, which we could not do.  And Shetland's very occasional sunshine dried the boards so they were very hard to bend without breaking.)

Her propeller was three-bladed, 10 or 12 inches diameter on a spindly 1 inch shaft, sticking straight out of the stern-post.  A cutout in the rudder sort of accommodated this.  Her stern-tube was very short, basically just enough to get through the stern-post.  The shaft then ran under loose floorboards to couple with the engine.  We never did find what the engine was - it was so rusted-and-crusted it was beyond salvage. ("Bolinder" semi-diesel seems possible??)  I do remember that the heaviest part of the engine was the massive flywheel - very necessary on a one-lung, slow-revving engine.

A little "wheelhouse" sat just aft of the engine.  This comprised a front and two sides, each with a plain glass window, and a roof and it was perhaps five feet high above the deck - don't forget the fisherman stood on boards just above the prop-shaft, perhaps two-and-a-half feet below deck.  This wheelhouse was barely wider than a man's shoulders, maybe two feet.  The engine was only just in front of the guy's knees so he could easily reach the controls, the gear-lever and the starting handle. 

There were deck beams at pretty nearly every frame to prevent "hogging" as well as to support the deck.  A fish-hatch of maybe 3 feet wide by four feet long was the only opening in the deck besides the wheelhouse - both had coamings four inches high.

I wish, Oh how I wish, I could offer some photos.  But I can't, so I shan't.  Sorry chaps, I don't have any photos of her.
I also wish I had managed to restore her, but that's another story ....

Geoff
Logged

gondolier88

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,347
  • www.coniston-regatta.co.uk
  • Location: Crake Valley, Cumbria
    • Coniston Regatta
Re: Displacement tests....
« Reply #7 on: October 30, 2009, 07:30:59 pm »

H,

Geoff,your boat sounded very quirky- full of character. Has someone restored her since do you know?

Here's a couple of double ender's in the SBA to have a look at, a bit of inspiration for you, the more you see the clearer an image of what you would like yours to look like I find..

From the top,

1- Amethyst
2- Arathusa
3- Lady Angela

Greg
Logged
Don't get heated...get steamed up!

benjaml1

  • Guest
Re: Displacement tests....
« Reply #8 on: October 31, 2009, 10:19:36 am »

Thanks gondolier88 those are along the lines that I shall follow I think..... :-)) Because of the clinker build & the wide beam, I shall make it a little more like a working boat...
Logged

andywright

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 546
  • Location: Upper Boat, Pontypridd, S Wales
Re: Displacement tests....
« Reply #9 on: December 28, 2009, 11:35:02 pm »

Wifey is at her mums, good time to work out ballast requirements.... 480 fluid ounces has her settling nicely. Yes, this is my winter steam project... :-)

What I shall do in the morning is put a few drops of oil based paint on the temporary "ballast" water ( inside) & that will leave me a datum. It's a Orion Moulding's Scottish Fifie, which is a little larger than I expected... :o



Any update on what you did with the hull.
Logged
Navigational Aids vessel Master. Old Conway 70-72

benjaml1

  • Guest
Re: Displacement tests....
« Reply #10 on: December 30, 2009, 11:47:01 pm »

Got my little man sorted. 1/6 th scale. Dirtied up the life vest by soaking in tea, gave a nice patina. Hat from Hong Kong, the rest from Japan and China. The steering wheel came from a tropical fish/aquarium dealer in the States for less than 6 US Dollars.... Sweet

Logged

Bernhard

  • Guest
Re: Displacement tests....
« Reply #11 on: December 31, 2009, 08:02:13 am »

Great...........look so real.........i like the age look to

Regards Bernhard
Logged

benjaml1

  • Guest
Re: Displacement tests....
« Reply #12 on: December 31, 2009, 08:52:59 pm »

Coming from you Bernard, that is indeed a compliment. I have nothing but admiration for your work...  :-))
Logged

Bernhard

  • Guest
Re: Displacement tests....
« Reply #13 on: January 25, 2010, 04:53:08 pm »

Hi.......Have you don eny more to the hull............
regards Bernhard
Logged

mogogear

  • Guest
Re: Displacement tests....
« Reply #14 on: January 25, 2010, 07:20:54 pm »

Geoff

Yes please - as a poor American with so little choice of moulded hulls on this side of the pond... Your's from Orion is the one I have had my eye on for a while.. The shipping keeps me at bay....The clinker detail is so well done and the added color is a bonus...Cannot wait to see how your build progresses. Your hull and your boiler!
Logged

benjaml1

  • Guest
Re: Displacement tests....
« Reply #15 on: January 30, 2010, 12:21:30 pm »

Hi.......Have you don eny more to the hull............
regards Bernhard

Sorry for the delay Bernard, No progress on the hull as yet, still concentrating on the steam plant. Looks like I'll meet my ballast requirements without extra weight...
Logged

benjaml1

  • Guest
Re: Displacement tests....
« Reply #16 on: January 30, 2010, 01:12:38 pm »

Just getting things laid out, condensate/oil separator/receiver & water tank to come. I've finished my boiler feedwater pump ( my own design) so need to plan where that goes....


Logged

benjaml1

  • Guest
Re: Displacement tests....
« Reply #17 on: January 31, 2010, 11:25:54 pm »

On perusing this forum, I have come to realise that perfection takes a long long time.  Actually this is an enlightenment for me.. I'll get to sea trials with a few basic details this year but shall continue my project until satisfied. However, I'm going to have to improve my woodcarving skills to match Bernhards piglets... Stunning work.  :-))

 Looks like I'm here for the long haul on this one Gentlemen...
Logged
Pages: [1]   Go Up
 

Page created in 0.1 seconds with 21 queries.