Re: Speed etc

Posted By: MarkW
Date: 2/12/02 11:00a.m.

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In Response To: Re: Speed etc (Mark R)

You're pretty much right except that if you use Dave Gerr's hull-speed formula (see link to try it yourself and you assume that he's cut about 800# in weight (because of the ballast), you're talking about a hull speed in the neighborhood of 10 knots (I used 23.8 for LWL and 2700 for displacement giving a 'Gerr' hull speed of 9.9 knots). Slow for an F-boat, of course, but still pretty fast -- assuming he's added a sailplan that can drive the boat to that speed with any consistency. Also, even with the standard waterline, the beam is nowhere near the max of 7'11". Without the ballast, I doubt it'd be much over 3-4 feet, which would give a ratio in the 6:1 to 8:1 range as a guess. That beast might actually work reasonably well.

Hull-speed calculator

Messages In This Thread

This Mac 26X has NOT been photographically altered -- Turol / Reynolds 21 -- 2/11/02 5:47p.m.

well-------- the workmanship looks decent. -- Charlie Jones, Lindsey 21, Magnolia Beach, Tx -- 2/11/02 6:05p.m.

Interesting - however -- Todd J -- 2/11/02 6:11p.m.

Let's see: I have an hunter 23.5 and a Hobie 17...Hmmmm -- Fat Frank -- 2/11/02 8:26p.m.

Well, I hope the guy.... -- Steve E/Montgomery 15 #102 "Scamp", Lake Pleasant,Phoenix, AZ -- 2/12/02 3:21p.m.

I can almost hear Doug from here in Illinois - - -" -- Nick Scheuer -- 2/11/02 6:13p.m.

That doesn't look like a 26X hull. -- Roger, Potter 19, Seattle -- 2/11/02 6:26p.m.

Right. It's not a 26X -- MarkW -- 2/11/02 6:53p.m.

Definitely not a 26X, Looks too much like a "sailing" hull -- Al - Seaward Fox -- 2/12/02 3:06p.m.

I guess my question would be, why? -- John Hill, Mac26X, Kansas City, Mo -- 2/11/02 7:52p.m.

Must be a retired engineer...... -- Rik, Rhodes 22 - Minnesota -- 2/11/02 9:09p.m.

Re: Definitely NOT a 26X hull. -- Jeff G. Indiana, US Yacht 21 -- 2/12/02 6:13a.m.

Re: Speed etc -- Mark R -- 2/12/02 10:47a.m.

 Re: Speed etc  -- MarkW -- 2/12/02 11:00a.m.

But it gets a lot more complicated for a trimaran. -- Roger, Potter 19, Seattle -- 2/12/02 3:09p.m.

Slowed the boat down? -- MarkW -- 2/12/02 10:49a.m.

Umm...pretty sure that's a Mac 26, not 26X -- Brian S, Annapolis -- 2/12/02 8:15a.m.

Very difficult to make a decent trimaran this way -- Tim C, F31 -- 2/12/02 10:57a.m.

Re: Very difficult to make a decent trimaran this way -- MarkW -- 2/12/02 11:06a.m.

Re: Increased wetted surface -- Don E. -- 2/12/02 10:59a.m.

Re: I forgot about the water ballast. -- Jeff G. Indiana, US Yacht 21 -- 2/12/02 11:59a.m.

Re: I forgot about the water ballast. -- MarkW -- 2/12/02 1:26p.m.

I don't know what he ended up with -- Jeff G. Indiana, US Yacht 21 -- 2/12/02 2:16p.m.

Is that a mac with training hulls?? -- Eric Jon - Capri 22 - Lake Mead Nv. -- 2/12/02 1:43p.m.

Benefit of the doubt -- Mark R -- 2/12/02 4:34p.m.