Scale propellers

[fooman2008]

I will post this in a different thread than my question(s) about electric motors.
I have a couple of views of Idaho (BB-42) screws when she was in dry dock, my question(s) are these.
http://www.maritimequest.com/warship_directory/us_navy_pages/uss_idaho_bb42_page_3.htm
The top pic has a great view of the screws, My question is with the scale I am using 1/35th I would guestimate the full size props as being somewhere in neighborhood of 18ft dia. full scale (almost 6.2 in. scale). Where can I find a prop(s) this diameter?
How important is it to try and find scale pitch?
Since I really have no intention of trying to get four screws/motors on this beast do I even need worry about scale pitch?
The underwater sections will be modified slightly for more beam and ease of construction giving her twin rudders. What would be the best way to determine the best size, number of blades, and pitch of the props I need?
thanx for any info offered
Foo

[mfr02]

How about a chandler store? You are basically building a full size launch that looks like a large model.

[patmat2350]

Sounds like you've already given up on "scale", so who cares if the pitch is right? Since you're building a real boat, you'll need a marine engineer for any more specific answers... or just swag it, you'll not be too far off!

For importantly, before you cut the first piece of wood... have you listed your design assumptions with regards to making this a safe craft? I'm assuming you'll be somewhat restricted in your ability to extract yourself in case of emergency.
Then, have you established a budget? Any idea how much lumber and resin are required? Fittings, etc? I've seen unfinished huge projects before, a lot of grief would have been avoided if the numbers were crunched ahead of time...

[toesup]

Where can I find a prop(s) this diameter?


I seem to remember someone in the distant past using one of these for a model..
http://www.trailertoys.com/plashitcovsp.html
I dont know what dia they are though... :confused:

[fooman2008]

Fortunately the superstructure of Idaho (as modified in 44) goes all the way to hull edge and I am planning on making the entire superstructure removable. (hopefully made from foam core or very light balsa). Intial plans are that it (the superstructure) will be held on with just a few strips of Velcro for holding it down, in case of emergency trust me I'll find a way to get out from under it!
Being just a little less than a 1000 miles from the ocean it will be a little hard to find a ship's chandler around here but I'll see what I can do.
Foo

[amdaylight]

Foo,

I would go to your local fishing store and see what they have in electric trolling motors.

Andre

[mfr02]

People sail launches and fishing boats on lakes and rivers - they have to buy their bits and pieces somewhere so a close look at yellow pages or the local equivalent might turn something up.

[Boatfox]

Make them....and a spare in case one gets "lost"