Some ideas

Strange encounters in trust vectoring dynamic bodies.

When steering a (stern mounted) OB on a monohull the boat actually goes another direction as oposite to the prop’s trust because the hull works as a rudder up front. The prop also try’s to encircle the beam vertically when cornering, thereby creating inward heeling.

On fast catamarans 2 canted OB’s (i want those!) can do the same job on heeling, but that may be too much for a mono hull. Making it more complex by putting the OB on the bow -for the sake of the argument- the boot will simply follow the OB but give NEGATIVE, OUTWARDS heeling! Ok, it might take the bow wave away but that’s another story.

I started wondering what will happen with the water bike design having the ob behind the front leg, wasn’t so sure if it would encircle its front leg or -due to the rear legs drag- follow the engine. That means wasnt sure it go left or right, heel in or out.

So I made another model, fairly accurate this time. Got a small RC outboard on the back of the front leg and guess what happened? From stationary it follows the OB and heels a little out, not good! But when getting only a little on speed it starts encircling the front leg going the other way (without steering) and give the rite inward heeling!

Must be strange going slow steering opposite! I wont be the last shooting my own balloons down and guess I’ll better finish the real thing and call it “test model”. Making the new waterbike model I again realised how precise a swath concept must be. Strange encounters in trust vectoring may turn out the smallest of problems / challenges…

 

in my search for a swath VPP i came acros lockheed martin marine systems its popular reading on swath / slice but no real WSA VPP or 3D units in the drawing above, witch looks like fun tho

 

ok, seriously, i'm back on the (water) bike, could not help my eye fell on this 14 page .pdf paper:
Optimal Design of Thruster System for Superconducting Electromagnetic Propulsion by: Shinsuke AKAGI, Kikuo FUJITA and Kazuo SOGA who investigated this superconducting truster on swath pods, propulsive efficiency is still to be improved, (sea water has a low conductivity) but i just wanted to let ya guy's know, i got to hurry or i am getting old... "time" the rabbit said asking for half a cup...

 

Wow, a one legged HYSWATH eek eek who dreamed that one up, great! (see demonstration at http://www.mapcorp.com/page4.html with thanks to Steve) Have -bla bla- that leg “somehow” retractable? Feel a bit yesterday’s paper now with my trike. Got the legs about done, making the ailerons now. Would it be allowable to have a cable only for the ailerons upward motion that pulls the leg down or is it going to swivel wildly?

Getting technical reactions (with or without sending my drawing) for a quote from the scaffolding, aluminum, stainless and steel trade here is almost hopeless. Yes they like the drawing but I had thought they could give the necessary strength estimates (like at http://www.efunda.com/formulae/solid_mechanics/beams/casestudy_display.cfm?case=simple_2symload with thanks to MDV for the address), confirm steel ads 40% weight on ali, diameter to wall thickness advice, pipe weight, advice locking systems, at least get the concrete sizes to figger the sleeves and a price. Not so! the few pipes I need are probably financially not interesting to them anyway.

On the net –and here on boatdesign- is more info! It made me think of some 80-page manuals for building a 2-sheeter rowing boat is no joke! Now I see that in reality it actually does make a lot of sense to calculate and detail in advance! That design spiral counts to the very last part!

Got a calendar but got too many open questions left that wiser be answered before pushing ahead to fast and goofing it up. So I’ll keep checking the piping industry here (and maybe reply’s on this mail?) because “ready in 2 months” should -without delay- be feasable! looking at the date, time fly's! yipster

but today i'm off to the beach, why not spy around a few cats

 

Hello all,
September now and must admit I’m slightly of scheme. It’s been a while since I updated this thread but last month my trike building came to a stop. Our sundancer had to return from France and now it’s missing its props. Otherwise the trike could have been in the water but propulsion needs an extra long shaft (and actually 15 to 20 instead of my 7.5 Hp OB). An extra long tail on a new OB cost 100 bucks more but having that conversion bought separate comes to 700. Pictured an electric drive but needs an external power source and only checking on these alternative’s recently. Anyone with fresh simpler ideas?

yipster

 

Can't wait to see some finished Pictures and specs!!!

 

i can only second that and thanks for the interest.
the sundancer is in the water and hope doing some tow testing with the trike soon. propulsion i'm searching for. ah, and dont forget to make a seat, wheel, cables etc. what looks so easy is still work and money, havent given up tho!

yipster

 

hi all, broke but now getting some insight in the mercruiser EFI setup. so the trike has to wait a little longer. was reading the tunnel boat news letter and it had a rather interesting article on OB torpedo drag. you all probably allready read but if not, here the article "How does a tunnel hull work? (Part 4)". for more info contact jimboat below or here on the forum.

in time i'll get the books, software etc!
yipster

 

13B in a Keel?

Did you ever find any one who used a gas engine in a keel bulb?

 

Guest,
i belive MAPC has its (diesel?) engine in the bulb? and i've seen a few other, it's interesting and can be done but is certainly not the easyest setup...

 

Keel bulb

Yipster:
I am toying with the idea of making a remote control torpedo sub. the smaller the engine the better.

Do you have a rough idea of how fast 100 hp would be able to push a 16" wide wave piercing torpedo.

 

you want to do that remote? not with a warhead i hope! and why a fast wave piercing torpedo that will hit wavemaking resistance, going fast the idea is to get out of that i belive?
see http://www.users.globalnet.co.uk/~fsinc/yachts/spreads/fred.htmand you can also use the search button here and check for "froude" or "resistance" for much more on this.
i did check submerged torpedo speeds versus HP and found a high curve diagram. here some not so easy to find info.

from another forum:
>yipster:
>>how much power / hp is needed to proppel a torpedo? who can help?
>I. Yes. Need dimensional info not here. 300kg not important unless vehicle "planes" (under/over water).
>It depends. Need info. Cyl Diameter, Length
>Drag Force = Cd.. * SomeArea * 0.5RhoV^2
>Wetsurf + Form + Wave + Lift-induced(not here - planing only)
> wsa; profileareas; L^2, shape factor; Liftarea
> consts consts consts consts
>Appropriate references for Cd....

A typical 21” (533mm) steam torpedo produced upwards of 300hp to achieve its maximum speed, usually around 45 knots. Many also had lower power settings available to achieve longer range. The Japanese Type 93 had what was probably the most powerful engine in a WW2 production torpedo, producing over 500hp. Aerial torpedoes usually produced about 150hp, good for about 40 knots. exception was the USN Mark 13, which produced only 98hp, good for about 33 knots.

http://uboat.net/allies/technical/fido.htm shows 12 kts on 5 hp for 680 lbs (=approximately 45? squered ft / close to the displacement of the waterbike design

Torpedo MK 24 - "FIDO" The First American ASW Acoustic Homing Torpedo
Size: 19" dia. x 84" long
Weight: 680 lbs.
Propulsion: Single propeller driven by a 5 HP electric motor-48 volt lead acid battery
Speed and Endurance: 12 kts for approx. 15 min.

at http://uboat.net/types/schwertw.htm another WSA sample going 30 knots but don’t say how much WSA or on how much hp/kw

The US Mark 14 ran at 46 knots -- some current models are reported to do as fast a 60 knots

here some hard to find links i collected, not sure if they are all still active.
http://www/warships1.com/Weapons/WTBR_WWII.htm
http://www.warships1.com/Weapons/WTJAP_WWII.htm
http://www.warships1.com/Weapons/WTRussian_WWII.htm
http://www.warships1.comWeaponsWTGER_notes.htm
http://www.diodon349.com/torpedoman/TM_Stuff.torpedoes.htm
http://www.militarism.navy.ru/torpedoes.htm
http://www.geocities.com/Pentagon/1592/ustorp1.htm
http://www.geocities.com/Pentagon/1592/ustorp2.htm
http://www.geocities.com/Pentagon/1592/ustorp3.htm
http://www.regiamarina.net/index_it.htm
http://www.geocities.com/Pentagon/1592/ustorp3.htm
http://www.geocities.com/ssvong/submarine/molch/torpedo.htm
http://www.dataphone.se/~ms/ubootw/torpedoes.htm
http://www.weymouthdiving.co.uk/torpedoes.htm
http://www.weymouthdiving.co.uk/torpjist.htm
Japanese Torpedoes: http://www.skypoint.com/members/jpb.torps.htm
Russian Torpedo Armament: http://www.militarism.navy.ru/torpedoes.htm
http://64.124.221.191/torps.htm) has a good primer on IJN torpedoes www.warships1.com.
http://www.j-aircraft.org/bbs/jship_config.pl?read=11800

 

from the "a question on drag" thread:

its a pitty the http://www.curj.caltech.edu/archives/vol1/1004005.pdf paper went ofline, hope it gets back without the wargames talk? very fast torpedos i heard of before but its sort of hush hush top secret. on whatever propulsion it still must be amazing friction reduction tho, perhaps start a new thread on it as Doug suggested?

yipster

 

Surface friction

Yipster,

Here in the US they have been running a TV commercial for a luxury sedan, Mercedes I think, that has its underside sheathed in dimpled material to reduce wind resistance (read surface friction) and noise.

Doug Carlson

 

Doug,
thanks for that info. i've been watching all european tv commercials for a while now but havent seen such dimpled surface materials other than on golfball's here yet... the tv spot is remarkable!
it was a thought and in boating is probably subject to other conditions, who knows?
meanwhile i learned that state of the art CFD programs wont input / handle this anyway yet but sure are interesting as well.
real high (submerged) speeds -and there is enough reason to belive- i can only wonder about and guess your thoughts are as good as mine; air ventilation and boundary area bleeding and?
dont expect getting the answers soon though.

keep me updated
yipster