long-cours.62
Guru
Did you have
A blog where you show your "old school" lady.
I find her look very 'sympathique'.
A blog where you show your "old school" lady.
I find her look very 'sympathique'.
Paravanes vs. Sea Gyro vs. Active Fins
- Thread starter Taras
- Start date
The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.
If you have answers, please help by responding to the unanswered posts.
Phil Fill
Guru
- Joined
- Oct 11, 2007
- Messages
- 2,919
- Location
- US
- Vessel Name
- Eagle
- Vessel Make
- Roughwater 58 pilot house
Here is the site. I talked to him and he swears by it, and send the drawings. Welcome & Family - Miss Nancy's Journal
Kasten marine also has twin keels and sails on many of their designs. A lot of interesting designs and ideas. He is at Port townsend WA, and who I might use to added the twin keels.
Roll Attenuation and Bilge Keels
Greatheart 58
This is the design that interest me the most. Fix Bilge keels and sails.
Anyway fun site to look at.
Kasten marine also has twin keels and sails on many of their designs. A lot of interesting designs and ideas. He is at Port townsend WA, and who I might use to added the twin keels.
Roll Attenuation and Bilge Keels
Greatheart 58
This is the design that interest me the most. Fix Bilge keels and sails.
Anyway fun site to look at.
long-cours.62
Guru
Thanks for
as all we can find concerning roll
an with more interrest
roll attenuation
For the first adress , for the another we already find and read
as all we can find concerning roll
an with more interrest roll attenuation
markpierce
Master and Commander
- Joined
- Sep 25, 2010
- Messages
- 12,557
- Location
- USA
- Vessel Name
- Carquinez Coot
- Vessel Make
- penultimate Seahorse Marine Coot hull #6
skipperdude;84986 I'm sure there is a web site to calculate wave frequency. Sd[/QUOTE said:
CPseudonym
Moderator Emeritus
Interesting subject that I found an equally interesting website. This was originally written as a response to a Trawler World mailing list posting.
Roll Attenuation and Bilge Keels
Roll Attenuation and Bilge Keels
Gulf Comanche
Guru
- Joined
- Dec 16, 2007
- Messages
- 1,045
- Location
- U.S.A.
- Vessel Name
- Old School
- Vessel Make
- 38' Trawler custom built by Hike Metal Products
LC62:
Sympathique, cest tres bien. Our boats look like cousins, though yours looks a lot faster than Old School.
GC
Sympathique, cest tres bien. Our boats look like cousins, though yours looks a lot faster than Old School.
GC
dvd
Senior Member
Paravane Rigging
Here's a link to a site describing the paravane rigging on a Nordhavn 46. This worked well for his extensive cruising and has been copied by several other boats that I know of. It may sound complex at first, but it is well thought out and allows the fish to be deployed quickly and safely from right outside the doors to the pilothouse.
dvd
Here's a link to a site describing the paravane rigging on a Nordhavn 46. This worked well for his extensive cruising and has been copied by several other boats that I know of. It may sound complex at first, but it is well thought out and allows the fish to be deployed quickly and safely from right outside the doors to the pilothouse.
dvd
Gulf Comanche
Guru
- Joined
- Dec 16, 2007
- Messages
- 1,045
- Location
- U.S.A.
- Vessel Name
- Old School
- Vessel Make
- 38' Trawler custom built by Hike Metal Products
DVD:
Thanks for the link, I really like that setup. Sure looks a lot safer than mine, I'll give it a try.
GC
Thanks for the link, I really like that setup. Sure looks a lot safer than mine, I'll give it a try.
GC
long-cours.62
Guru
May be you can explain to me
I went on the Kasten site " Beam vs ballast" and at one moment he wrotte :
« …For example, 2,000 pounds of ballast located 5 feet from the roll axis will yield a Rigting Moment (Torque) of 10,000 lb-ft, and a Roll Moment of Inertia of
5^4 x10,000 = 3,125,000 lb-ft^4. By comparison, a 200 pound mast located 25 feet
from the roll axis will introduce a Heeling Moment of 5,000 lb-ft, but will have a Roll Moment of Inertia of 25^4x200 = 78,125,000 lb-ft^4... »
I don’t understand why on this example for the ballast the 2000 pouds was multiplicated by the 5 feet for obtain 10000 and after 5^4x 10000 and at contrario
for the mast the designer took directly 200 (and not doing like the ballast 200 x 25 before appliced the formula)
I could understand if the same way is used for both , but I don’t understand when it is not the same.
Did you have an answer ?
and just for the "fun" of see 'disaster' made by the roll
Le roulis paramtrique
I went on the Kasten site " Beam vs ballast" and at one moment he wrotte :
« …For example, 2,000 pounds of ballast located 5 feet from the roll axis will yield a Rigting Moment (Torque) of 10,000 lb-ft, and a Roll Moment of Inertia of
5^4 x10,000 = 3,125,000 lb-ft^4. By comparison, a 200 pound mast located 25 feet
from the roll axis will introduce a Heeling Moment of 5,000 lb-ft, but will have a Roll Moment of Inertia of 25^4x200 = 78,125,000 lb-ft^4... »
I don’t understand why on this example for the ballast the 2000 pouds was multiplicated by the 5 feet for obtain 10000 and after 5^4x 10000 and at contrario
for the mast the designer took directly 200 (and not doing like the ballast 200 x 25 before appliced the formula)
I could understand if the same way is used for both , but I don’t understand when it is not the same.
Did you have an answer ?
and just for the "fun" of see 'disaster' made by the roll
Le roulis paramtrique
FF
Guru
- Joined
- Oct 12, 2007
- Messages
- 22,552
Saw a new addvert . the Gyro is now being used in small (30) ft outboards.
Phil Fill
Guru
- Joined
- Oct 11, 2007
- Messages
- 2,919
- Location
- US
- Vessel Name
- Eagle
- Vessel Make
- Roughwater 58 pilot house
Kasten is usually at the Trawler Fest, Anacortes May 16th thru 19th, if I see him I will ask. We have met/talked several times. His office is Port Townsend across the Puget Sound from Anacortes. We plan on going to Trawler Fest Saturday, May 19th, if weather is reasonable, go on a few of the bigger, new, interesting boats, have lunch and visit. 
I been thinking about the paravanes again. Decide to have the shop make the side chain plates, 1” aluminum, to attach the poles and stays to the hull. The shop loves my hand drawing that sort of gives them the general idea. NOT! Then will have the main pieces; fish, poles, new mast, and chain plates.
I been thinking about the paravanes again.
Decide to have the shop make the side chain plates, 1” aluminum, to attach the poles and stays to the hull. The shop loves my hand drawing that sort of gives them the general idea. NOT! Then will have the main pieces; fish, poles, new mast, and chain plates. sunchaser
Guru
- Joined
- Apr 9, 2008
- Messages
- 10,196
- Location
- usa
- Vessel Name
- sunchaser V
- Vessel Make
- DeFever 48 (sold)
Longcourse
Rather than giving a long winded discourse, suggest you google "moment arm" and "boat stability calculations."
In a nutshell:
The mast's (rigging and sail weight too) CG of 200# is 25' above the boats CG or providng a tipping arm of 5000#. This 5000# tipping arm is more than counteracted by 2000# of ballast 5' below the boat's CG. This leaves excess ballast to cover the wind induced loads.
For cruisers, removing 200 to 500# of crap from the flybridge and leaving it ashore can improve the boat's righting moment by 2000 to 5000 # assuming the boats's CG is 10' below the removed crap.
Or, the bigger the dinghy and outboard on the boat deck, the more unstable the cruiser.
Rather than giving a long winded discourse, suggest you google "moment arm" and "boat stability calculations."
In a nutshell:
The mast's (rigging and sail weight too) CG of 200# is 25' above the boats CG or providng a tipping arm of 5000#. This 5000# tipping arm is more than counteracted by 2000# of ballast 5' below the boat's CG. This leaves excess ballast to cover the wind induced loads.
For cruisers, removing 200 to 500# of crap from the flybridge and leaving it ashore can improve the boat's righting moment by 2000 to 5000 # assuming the boats's CG is 10' below the removed crap.
Or, the bigger the dinghy and outboard on the boat deck, the more unstable the cruiser.
markpierce
Master and Commander
- Joined
- Sep 25, 2010
- Messages
- 12,557
- Location
- USA
- Vessel Name
- Carquinez Coot
- Vessel Make
- penultimate Seahorse Marine Coot hull #6
Better yet, have no flybridge at all. A mast is bad enough, especially when it's two/three times taller than typical.
Last edited:
long-cours.62
Guru
Thanks for your sugestion
But I doing that at ENMM (it is school for professional sailor in France).
What I do not understand it is on the sample the designer do not use the same way for the ballast and for the mast and something don't look logic.(may be just for me :lol
But I doing that at ENMM (it is school for professional sailor in France).
What I do not understand it is on the sample the designer do not use the same way for the ballast and for the mast and something don't look logic.(may be just for me :lol
Similar threads
