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which is faster? flat or flying?
http://www.hobie.com/forums/viewtopic.php?f=14&t=19574
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Author:  MIKE [ Sat Jan 09, 2010 6:06 pm ]
Post subject:  which is faster? flat or flying?

is it faster to try and sail as flat as possible or fly a hull? which actually has less drag?

Author:  Al [ Sat Jan 09, 2010 6:45 pm ]
Post subject:  Re: which is faster? flat or flying?

Normally and under small wave conditions or even large wave conditions, optimal speed will be achieved with the windward hull barely touching the water. If you can call that flying a hull well then that's it. If you start raising the hull any more than that you'll start sacrificing speed because of drag.

Author:  Banzilla [ Sat Jan 09, 2010 8:14 pm ]
Post subject:  Re: which is faster? flat or flying?

More than drag, The higher you fly the hull, the more wind you will be dumping off the sail.

Author:  srm [ Sat Jan 09, 2010 8:48 pm ]
Post subject:  Re: which is faster? flat or flying?

Basically, the power that the rig generates has to be balanced by the leverage of the crew weight out to windward. The higher the hull flies, the less leverage generated by crew weight. So having the boat flat is critical. Additionally, when you fly a hull, the force generated by the rig just pushes the leeward hull down into the water creating drag rather than driving the boat forward.

So, the max power is generated from the rig when the boat is absolutely flat and the crew is hiking horizontal to the water. However, when the boat is perfectly flat, the windward hull causes some excess drag, so the best compromise is generally to have the windward just touching the water with the crew fully trapped out.

sm

Author:  YoungSailor [ Sun Jan 10, 2010 12:43 pm ]
Post subject:  Re: which is faster? flat or flying?

Do you control how much you fly your hull with the traveller or the mainsheets?

Author:  Al [ Sun Jan 10, 2010 1:37 pm ]
Post subject:  Re: which is faster? flat or flying?

In a given course and wind wave condition, set your traveler in a setting that will permit you to sheet in or out in the puffs so as to achieve this condition (windward hull just touching the water). Travel out if you are overpowered, but the goal is to be able to sheet in in the lowest wind in order to not lose speed, and still be able to sheet out in the puffs and keep that hull just barely touching the water.

Author:  getwetsailing [ Mon Jan 11, 2010 9:05 pm ]
Post subject:  Re: which is faster? flat or flying?

Wile having the windward hull just touching is faster, flying is more fun!

Author:  BobMerrick [ Wed Jan 13, 2010 6:12 pm ]
Post subject:  Re: which is faster? flat or flying?

The windward hull should be up enough to have about a 3 to 4 foot water line.

Author:  Hobie WP [ Wed Jan 13, 2010 10:52 pm ]
Post subject:  Re: which is faster? flat or flying?

Definatly just flying a hull but flying clear of the water is great fun ! We sail Hobie 16 ' s at Theewaters Kloof Dam in South Africa and in the summer months sail in real strong wind 15 knots - 47 knots . On our first day out on summer vacation went sailing in light breeze and went to the dam wall which is 9 km away and as Murphy's law has it the wind picked up to well over 35knots and we had to sail downwind in super strong wind with waves of 2 meters , what a rush ! But avoid the pitchpole , ask me . Hobies rule !

Author:  MBounds [ Thu Jan 14, 2010 6:57 am ]
Post subject:  Re: which is faster? flat or flying?

Check out the boats approaching the weather mark at the 16 North Americans:
Image

Author:  mmadge [ Thu Jan 14, 2010 9:23 am ]
Post subject:  Re: which is faster? flat or flying?

The 16 is a very tricky boat to keep the boat attitude just perfect for an extended priod of time.Really good guys have the Zen like touch on the helm ,sheet and traveller and weight placement to keep it just right for extended periods.I think when it gets windy if you can bat about 75% on proper sheeting and sterring you will be doing pretty good.Just remember the top guys are in the 90% + range.

This is just about perfect.

Image


This is getting a little too high

Image

This is way to high

Image

Author:  Al [ Thu Jan 14, 2010 9:38 am ]
Post subject:  Re: which is faster? flat or flying?

BobMerrick wrote:
The windward hull should be up enough to have about a 3 to 4 foot water line.



Not challenging an expert´s advice but what exactly do you mean by 3 to 4 foot waterline ?

Author:  Banzilla [ Thu Jan 14, 2010 10:08 am ]
Post subject:  Re: which is faster? flat or flying?

What he is trying to say is, keep just enough of the hull in the water so that the water line on the side of the hull is 3 or 4 feet long. In other words, you want to just be skimming the surface of water with the bottom edge of the hull.

Somebody mentioned that flying high is more fun than going fast. I will disagree, getting the boat to go as fast as possible for the conditions is just as much fun as flying on the edged of tipping over. Both are a challenge and take a fare amount of skill.

Just my .02

Sam

Author:  Al [ Thu Jan 14, 2010 10:28 am ]
Post subject:  Re: which is faster? flat or flying?

OK got it, that is in line with my own thoughts then. In big waves only the crest will come in contact with the windward hull.

Author:  janek.w [ Mon Feb 01, 2010 12:30 pm ]
Post subject:  Re: which is faster? flat or flying?

A flat boat is a fast boat, BUT there is more hull in the water. The best is to try and get the windward hull barley out of the water. This will get you optimal speed

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