Paddleducks
Large Paddler Builds => General discussion (Large) => Topic started by: Eddy Matthews on November 16, 2006, 08:39:39 PM
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One thing that seems to have been forgotten in all these threads is the hulls displacement.... Using small rowing boats, skiffs, dingys etc etc is fine - But.....
Have any of you calculated the displacement for your hull before starting to add vast amounts of weight in the form of engine/boiler, paddlewheels, paddleboxes/sponsons, cabin etc etc....
I'm afraid you may find a lot of them will either have very little freeboard, or they'll sink!
The second thing to consider is stability - your adding large overhanging weights on either side of the boat when you fit paddlewheels/sponsons, and these boats were never intended to carry that sort of load. Be very careful unless you like capsizing in mid-stream!
My apologies if that sounds negative, but they are two items of prime importance and they seem to have been all but ignored....
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Thanks Eddy, I have been thinking of that, I only just bought a hull today, and it is 5'7'' wide. The sponson decks should only protrude from the boat about 1'. Thanks for the tip though!!
Cheers
:beer
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your right Eddy :D
displacement was brought up very briefly in my post "under marine steam plant" when I was making a point about planning of these boats and that they can't be slapped together without a plan and calculations
cheers Anthony
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...just waiting to get the hull ready first Eddy! No intentions of doing ANYTHING until that is ready! Then we will be doing all the calculations...because we're doing it my way, not my grandpa's way (he wants to just slap bang the thing together!)\
Displacement is the weight of the boat ins't it...the same amount it weighs is the amount it displaces in the water and as such needs that amount of water to run correct?
I have thought weight to be an issue...personally I think Grebe needs more weight in her...she sits so high in the water that she's barely floating...in fact I may have bought a plane! Weighing her down should sit her deeper in the water...less chance of capsize! I hope!
I might go up and work on her tonight get more primer on. It's a dam nice day considering the weather lately!
Sean
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Yes, I have a relation that has just told me to slap a boat together, I tell them that it is not that easy, many calculations are needed and plans!! Some people! Well, I must get to work on mine, can anyone recommend a designing program? Or just good old pencil and ruler!!
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Hi PD's - James ...from your postings you are PC savy .... try a GOOGLE search on Navi-CAD which from memory is a free cut down version of naval design archicture [but still was in an older DOS format, rather than Windows based]
Do not dismiss this program.... if you are OK with your maths there is no 'rule of thumb' multiplying an answer by 0.6..... :?: :idea: :arrow:
Failing that the AutoDESK people have their latest marine CAD sotware @ $9,000.00 AUD for a single licence :oops: :oops: :oops: :oops:
Possibly the best & cheapest option is to get 10 or 15 mates [girls & guys]... get them to provide their certified weight sticker & add them progressivly until the vessel sat at the correct waterline etc... final trimming could be by a few :beer... then add them up as they departed & ....= the Kg of equipment you can install .... :weight ... Derek
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Thanks Derek!!
I will get together a few people and 'things' with weight stickers, and then see how much it will hold!!
But firstly I need to get the hull into a floating state, it still has 'oles in it!!
Thanks heaps,
:beer