Anyone who knows the displacement of a Naca 5.5 hull? Extrapolated and got an guesstimate of ca 1500 lbs.



--
Brgds
Lars

Frankentri 5.8/5.5/Inter20
Aerow trimaran foiler

https://www.facebook.com/groups/1192604934176635
--

probably a very complicated addition of different measurements, but, once you know the total volume you can figure it out. water is 8lbs/gallon.

--
1978 H18
1983 H18 (some of it)
--

Water density is defined as 8.34lbs/gallon if fresh and 8.57lbs/gallon if sea. Using metric units, water is 1kg/dm3 and 1.03kg/dm3 respectively . But 8 is good enough for ballpark figures

Just found a figure from multihull designer Richard Woods, with an estimate of 600kg for an older F18 hull. The 5.5 is probably just a little slimmer, but I will use this in my calculation.



Edited by revintage on Mar 12, 2022 - 04:17 PM.

--
Brgds
Lars

Frankentri 5.8/5.5/Inter20
Aerow trimaran foiler

https://www.facebook.com/groups/1192604934176635
--

I have to ask why you need to know, is it for comparing buoyancy? Just curious because it's something you can't really alter. By the way, if memory suites me, "displacement" when referring to sailboats is the water displaced by the hull when the boat is floating. The weight of the water displaced should be the same as the weight of the boat? Someone out there please correct me if I'm wrong.

--
Bill Townsend
G-Cat 5.0
Sarasota
--

Call it whatever you like, full buoyancy at total immersion or total displacement . Anyway, as Woods has given a good approximation, I will use that. Good to know for your calculations, when building a beach trimaran with beachcat floats. In this case 5.5 floats and Tornado center hull.



Edited by revintage on Mar 14, 2022 - 06:51 AM.

--
Brgds
Lars

Frankentri 5.8/5.5/Inter20
Aerow trimaran foiler

https://www.facebook.com/groups/1192604934176635
--

revintage

Call it whatever you like, full buoyancy at total immersion or total displacement . Anyway, as Woods has given a good approximation, I will use that. Good to know for your calculations, when building a beach trimaran with beachcat floats. In this case 5.5 floats and Tornado center hull.Edited by revintage on Mar 14, 2022 - 06:51 AM.

Are you hoping to have enough volume to fly the main hull? Or just to see how hard you can push it?

--
Scott

Prindle Fleet 2
TCDYC

Prindle 18-2 Mod "FrankenKitty"
Tornado Classic "Fast Furniture"
Prindle 19 "Mr. Wiggly"
Nacra 5.8 "De ja vu"
Nacra 5.0
Nacra 5.8
Tornadoes (Reg White)
--

At the moment calculating RM, SA and making load cases for the beams. Although the floats has 150% buoyancy wrt to boat&crew weight, this indicates flying the main hull might maybe be possible.



Edited by revintage on Mar 15, 2022 - 08:28 AM.

--
Brgds
Lars

Frankentri 5.8/5.5/Inter20
Aerow trimaran foiler

https://www.facebook.com/groups/1192604934176635
--

Subscribing

This is the plan so far:




Edited by revintage on Mar 21, 2022 - 02:15 PM.

--
Brgds
Lars

Frankentri 5.8/5.5/Inter20
Aerow trimaran foiler

https://www.facebook.com/groups/1192604934176635
--