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 Post subject: Re: Invidious comparisons
PostPosted: Thu Aug 03, 2017 4:04 pm 
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Joined: Thu Nov 07, 2013 9:16 pm
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Location: Northeast Ohio, USA
Boat Name: SL Nyitra
Lopez Mike wrote:
The usual low comment about water skiing.


You can get a pontoonboat into a planning mode with a big enough engine - I saw one in Chautauqua a weeks ago.

My neighbor, who is interested in Nyitra, mentioned water skiing. I said - show me a 6HP gasoline engine that can get Nyitra on step! He conceded that you could find no such beast.

-CB


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 Post subject: Re: Invidious comparisons
PostPosted: Thu Aug 03, 2017 4:41 pm 
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Joined: Sat Aug 13, 2011 6:41 pm
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Location: Middle Earth
Boat Name: B.N.Y.S.
Lopez Mike wrote:
I still like mine as it rolls off the tongue better. "Furlongs per Fortnight."



It does, but only really because of the aliteration.

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 Post subject: Re: Invidious comparisons
PostPosted: Thu Aug 03, 2017 8:41 pm 
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The same 'aliteration' that makes good whiskey roll off the tongue?

I just ordered a set of launch plans from Reuel Parker for a boat such as Steve Weaver is building. I am so stoked about all of this than I am now under an edict to stop talking to Barbara about the project. The cat is still listening.

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 Post subject: Re: Invidious comparisons
PostPosted: Fri Aug 11, 2017 10:26 pm 
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I was a little bit shocked today to realize that our dock partners largest boat which is still shorter than the 24 ft of Nyitra has approximately 100 x the horsepower of Nyitra! 500 vs 6 , I would say both float and both move in the water but that's about where the comparison ends.

What if there was another way we could express horsepower to show the Ridiculousness of having 500 horsepower in a 20 ft boat?

My doc partner did just give me a bunch of free wood for Nyitra, so he's not all bad. :)

-CB


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 Post subject: Re: Invidious comparisons
PostPosted: Fri Nov 03, 2017 7:04 pm 
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I find that I am far more impressed with skippers who can properly manage a boat whose Ft^2/HP ratio is > 10

Feet being length of the vessel in Feet.

Example:
Nyitra - (24ft*24)/6HP = 96 Ft^2/Hp

96 - Nyitra
33.8 - Barzan One of the Largest active Ship in the world
25.8 - 9.9HP common gasoline 16ft skiff
24.01 - SS Badger
16.91 - RMS Titanic
2.88 - Fern Lodge(Family) 24ft 200hp gasoline motorboat
1.35 Kawasaki Jetski 2017 Kawasaki Jet Ski Ultra 310LX
1.152 My dock partners "500HP" 24ft supercharged boat

How does your launch measure up to this useful ratio?

-CB


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 Post subject: Re: Invidious comparisons
PostPosted: Fri Nov 03, 2017 8:04 pm 
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Location: Menlo Park, CA
Boat Name: Otter
cyberbadger wrote:
I find that I am far more impressed with skippers who can properly manage a boat whose Ft^2/HP ratio is > 10

Feet being length of the vessel in Feet.

Example:
Nyitra - (24ft*24)/6HP = 96 Ft^2/Hp

96 - Nyitra
33.8 - Barzan One of the Largest active Ship in the world
25.8 - 9.9HP common gasoline 16ft skiff
24.01 - SS Badger
16.91 - RMS Titanic
2.88 - Fern Lodge(Family) 24ft 200hp gasoline motorboat
1.35 Kawasaki Jetski 2017 Kawasaki Jet Ski Ultra 310LX
1.152 My dock partners "500HP" 24ft supercharged boat

How does your launch measure up to this useful ratio?

-CB


Why squared ft? Why not lbs/hp? The latter more accurately captures the physics of the situation, esp. over a wide range.

- Bart

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 Post subject: Re: Invidious comparisons
PostPosted: Fri Nov 03, 2017 9:10 pm 
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Joined: Fri Nov 27, 2009 5:56 pm
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Location: Northwest Detroit
Boat Name: Iron Chief
Not sure why it is being assumed that low power level of propulsion somehow makes maneuvering more difficult. Most straight shaft power boats at idle create too much propwash over the rudder for tight places. My Chris Craft at 215 hp and single screw with a rudder, forget the throttle, play forward and reverse coming in to the dock and be ready to fend off, if it's windy good luck. Backing up, doesn't matter what the helmsman does, it goes back and to port. Just have to plan a strategy where that works to your advantage. Someone on the dock kicking it in the right direction goes a long way. Forward, under way, handles like a dream.

Iron chief will respect the rudder backing up as long as she's cranked hard to starboard, a straight line can be achieved, but at higher than safe speeds. I plan on increasing the rudder size.

-Ron


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 Post subject: Re: Invidious comparisons
PostPosted: Fri Nov 03, 2017 11:09 pm 
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DetroiTug wrote:
Not sure why it is being assumed that low power level of propulsion somehow makes maneuvering more difficult.

It shows that maneuvering is done with skill and not muscling trough situation with excess HP.

I'm just trying to explain why I like and respect sailboating, steamboating, kayaking, canoing, small underpowered-moderate power skiffs, large ships, over just gobs of HP on anything that floats.

Different folks may value things differently of course.

-CB


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 Post subject: Re: Invidious comparisons
PostPosted: Fri Nov 03, 2017 11:42 pm 
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Location: Lopez Island, Washington State, USA
Boat Name: S.L. Folly
Hm . . .

My old 5 liter hydroplane at 630 h.p. and 1800 lbs. was quite controllable. As long as you only turned left, that is.

Of course I'm referring to it's normal operating envelope which was normally between around 90-100 m.p.h. in the corners and 140 on the straights. It was direct drive so backing was not an issue. As soon as you started the engine you were under way.

Now control in the Z direction was sometimes an issue. Once it decided to go positive in pitch things got exciting right now!

Those big boats you reference had little need for serious ship handling in tight quarters. Tugs and all that stuff.

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 Post subject: Re: Invidious comparisons
PostPosted: Sat Nov 04, 2017 12:06 am 
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Part of a good metric, for convenience, should not rely on things that people may not remember about their boat. More likely they will know length rather then then weight.

Ok I said maneuverability, but maybe it's not exactly maneuverability. I just put the boats I like on the top and boats that I have no interest in on the bottom and tried to find a simple ratio.

Maneuverability weighted to make big ships higher up on the list

-CB

P.S. I started with Ft/Hp, but it was not putting the big ships in the good category.


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