Pros and cons of steel sailboats - Page 46 - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Boat Review and Purchase Forum
 Not a Member? 


Like Tree1721Likes
Closed Thread
 
LinkBack Thread Tools
  #451  
Old 08-07-2013
mark2gmtrans's Avatar
sailing soon
 
Join Date: May 2013
Location: Texas
Posts: 813
Thanks: 2
Thanked 30 Times in 30 Posts
Rep Power: 2
mark2gmtrans is on a distinguished road
Send a message via Yahoo to mark2gmtrans
Re: Pros and cons of steel sailboats

Bob,

I have to say I am a bit jealous, you braved those salmon infested waters with only the protection offered by your fine choice in Hawaiian flowerdy shirts to protect you from the vicious salmon. As a fellow Hawaiian flowerdy shirt connoisseur I think the choice of the blue shirt was an excellent choice as it offers superior protection in the case of salmon attack.

I know the sailing must have been great, and even if it was on a strange tri hulled thing it was still a day spent enjoying the thrill of risking your life on the waves of the salmon infested waters of the great PNW. I will have to stop by sometime when I get back on the water next year and perhaps we can compare Hawaiian shirts and swap tales of close calls with the terrifying salmon.
__________________
It is good to learn from your mistakes, but much better to learn from the mistakes of others...
  #452  
Old 08-08-2013
blt2ski's Avatar
Senior Member
 
Join Date: May 2005
Posts: 6,694
Thanks: 0
Thanked 21 Times in 20 Posts
Rep Power: 10
blt2ski will become famous soon enough
Re: Pros and cons of steel sailboats

I was in Port Townsend today. Behind a building was some "little" wide flat bottomed 4 or 5 spreader ed rig, name of "Glory" or some such name.......in the front was something I envision came from a BS design. Not sure that thing would sail under its sails ina blinken hurricane! The keel, probably of steel like the rest of the boat appeared to be, had a flat 6" plate going forward! Talk about resistance! Mean while the keel on the other boat other than the bulb that was down at least 8-10' will swag, was all of 2-3" thick! Maybe a foot of hull in the water. The hull on the steely was at least 3-4' down, then maybe 3' of keel............

I know which of those boats would be more fun no matter the sailing I did, excepting when trying to sail on a rocky REEF some where!

Marty
__________________
She drives me boat,
I drives me dinghy!
  #453  
Old 08-08-2013
mark2gmtrans's Avatar
sailing soon
 
Join Date: May 2013
Location: Texas
Posts: 813
Thanks: 2
Thanked 30 Times in 30 Posts
Rep Power: 2
mark2gmtrans is on a distinguished road
Send a message via Yahoo to mark2gmtrans
Re: Pros and cons of steel sailboats

Quote:
Originally Posted by blt2ski View Post
I was in Port Townsend today. Behind a building was some "little" wide flat bottomed 4 or 5 spreader ed rig, name of "Glory" or some such name.......in the front was something I envision came from a BS design. Not sure that thing would sail under its sails ina blinken hurricane! The keel, probably of steel like the rest of the boat appeared to be, had a flat 6" plate going forward! Talk about resistance! Mean while the keel on the other boat other than the bulb that was down at least 8-10' will swag, was all of 2-3" thick! Maybe a foot of hull in the water. The hull on the steely was at least 3-4' down, then maybe 3' of keel............

I know which of those boats would be more fun no matter the sailing I did, excepting when trying to sail on a rocky REEF some where!

Marty
Marty I think I prefer to try to sail on WATER and not on the reefs. Most likely I will be okay without a BS design.
__________________
It is good to learn from your mistakes, but much better to learn from the mistakes of others...
  #454  
Old 08-08-2013
Senior Member
 
Join Date: Nov 2002
Location: New York
Posts: 5,569
Thanks: 0
Thanked 14 Times in 14 Posts
Rep Power: 14
bubb2 has a spectacular aura about bubb2 has a spectacular aura about bubb2 has a spectacular aura about
Re: Pros and cons of steel sailboats

Quote:
Originally Posted by blt2ski View Post
I was in Port Townsend today. Behind a building was some "little" wide flat bottomed 4 or 5 spreader ed rig, name of "Glory" or some such name.......in the front was something I envision came from a BS design. Not sure that thing would sail under its sails ina blinken hurricane! The keel, probably of steel like the rest of the boat appeared to be, had a flat 6" plate going forward! Talk about resistance! Mean while the keel on the other boat other than the bulb that was down at least 8-10' will swag, was all of 2-3" thick! Maybe a foot of hull in the water. The hull on the steely was at least 3-4' down, then maybe 3' of keel............

I know which of those boats would be more fun no matter the sailing I did, excepting when trying to sail on a rocky REEF some where!

Marty

I agree, if we would apply BS's logic to cars we would all be driving Sherman tanks.

I been biting my lip reading this thread as I have been involved in a sailboat collision. My little plastic benne was run down behind by a 45 foot Searay which was on plane at the time. over $60,000 damages between both boats but nether boat was holed or sunk. I know first hand how tough plastic boats are.

It can happen
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Never Forgotten

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
  #455  
Old 08-08-2013
blt2ski's Avatar
Senior Member
 
Join Date: May 2005
Posts: 6,694
Thanks: 0
Thanked 21 Times in 20 Posts
Rep Power: 10
blt2ski will become famous soon enough
Re: Pros and cons of steel sailboats

mark,

I'll have to take a pic of the boat friday if I am up that way. I have to admit, it was not a "BAD" looking boat. This one looked ok overall. It is what I think one of BS's boats should look like in "orgami" construction. It had a pilot house design. which could be good around this area considering how gray it can be.......BUT, that particular design is not what I would have in mind.

On the other hand, in Port Angelas, was an older Fisher pilot house motor sailor. Even when those came out, I liked the look of them! They looked PNW at its best. Not sure how well they sail per say, but have to be better than that steely I saw today! ALong with way the heck better looking! one I could handle being seen in! or having the best women in ones life's name on the rear!

marty
__________________
She drives me boat,
I drives me dinghy!
  #456  
Old 08-08-2013
blt2ski's Avatar
Senior Member
 
Join Date: May 2005
Posts: 6,694
Thanks: 0
Thanked 21 Times in 20 Posts
Rep Power: 10
blt2ski will become famous soon enough
Re: Pros and cons of steel sailboats

Bubb,

Forgot about that incident! A few weeks ago, a member of my YC had there barely 4-5 month old Jeanneau 44DS hit at a dock by a big power boat too. Supposedly only caused 20K in damage.........that is the initial estimate, along with losing ANY warranty they had from Jeanneau! That has to add something to the total in some way shape or form. But the boat motored and made it back from BC into the US to the dealers yard where it is out of the water, either still waiting to get repaired, or being repaired as we speak.

From folks that saw the incident, it was scary, surprising the boat held up. As much as folks like to say Jeanneau's, Beneteau's Even Hunter will fall apart, they are stronger than one thinks.

On other fronts, HERE is a race I am doing in two weekends, if anybody can donate to the cause, please do so! any names added to the donation part, will go on an older main sail I am painting pink! One can see the person we are sailing in memory of on that page.

Marty
__________________
She drives me boat,
I drives me dinghy!
  #457  
Old 08-08-2013
Senior Member
 
Join Date: Sep 2011
Location: Michigan
Posts: 181
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 4
BryceGTX is on a distinguished road
Re: Pros and cons of steel sailboats

Quote:
Originally Posted by mark2gmtrans View Post
Okay, let's address the math here....

First we need know that to figure the force of the impact, we are going to have to calculate the Impulse of Force, which is the force of the impact in PSI in this case over the period (length of time) of the impact. In order to know the force we have to know the weight, the speed and the size of the impact point, and to get the Impulse on that we need to know the duration.

From there it is a simple little calculus problem, and we can get it all done in just a few minutes. So, we figure that the length of one of Brent's keels is about 60 inches long by 6 inches wide at the point of contact. ( I tried to look up some of Brent's designs on sailboatdata.com like I do with Bob's or Roger Long's but I found this photo, and I am just kind of guessing on the actual length, at the end of the story it won't matter.

So we have a weight (per Brent) of 20,000 lbs
A hull impact area of 360 square inches maximum.
We will designate a forward hull speed of 10 knots which is 26.465 per sec
A downward force of 954417 N on the keel, and that is not a full calculation, but there are too few here who would understand the math to make it worth the effort.

So that translates to 214561.47 PSI

Score Fukushima Debris Field 1 BS hull Zero

In other words a full on 10 knot collision would poke a hole in your boat, and that force is the force that would occur along the entire 360 square inches, angle it slightly and it goes way up. I know my math is dirty on this because the formula I used was not the full formula, which gets to be fairly complex because I would have to estimate too many of the numbers. I used

Impact Force(F): 2 m vt

Which is really too simple. The actual formula for calculating keel impact force is longer and more complicated and I would have to calculate too much stuff after a very long day at work.

However for those interested the whole formula is here....

Guide Specifications and Commentary for Vessel Collision Design of Highway ... - Aashto - Google Books
It seems to me you are speaking apples and oranges. Brent is simply giving a calculation that is perfectly correct. His statement is only to give the impression that the keel is strong. And his numbers are correct.

On the other hand, you are providing a trivial collision calculation that is quite far from reality and does not reflect what sailboats do. For instance, my boat is 20,000 lbs. Real-life, I hit a sandbar at about 8 knots, stopped the boat dead. Threw us both head over heels, but did no damage to the keel or the hull.. not even a crack in the keel to hull joint. Your calculations indicate our boat was holed!!!

You are failing to include the dynamic effects of deformation of the boat or the item collided with. Inertial effects are poorly represented.
Bryce
  #458  
Old 08-08-2013
Senior Member
 
Join Date: Sep 2011
Location: Michigan
Posts: 181
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 4
BryceGTX is on a distinguished road
Re: Pros and cons of steel sailboats

Quote:
Originally Posted by mark2gmtrans View Post
Brent,

I know you are severely challenged on the math because you just cannot in good conscious be saying that I could exert three million pounds of force on one of your thin skinned little boats and not squish it flat, much less thinking that I could give your hull a three million pound impact and not send the thing to the moon with a GIANT GAPING HOLE IN IT.

Exert a three million PSI impact on the keel and it would probably exit the hull through the deck and land somewhere on Mars.

But, I am happy if you are happy, so if you have people buying your BS boats then go forth be fruitful and multiply.
You are talking about two things here. Million pound forces and impact forces. These are quite different things the way I see it. You are also mixing PSI and forces.

Brent specifically mentions pounding forces from waves, so it might be interesting to determine what these pounding forces might be.

My boat, 20000 lbs, say 10000 kg, drops off a 10 foot wave into a trough. Due to dynamic forces decelerates in about a foot or so. Acceleration of gravity is 9.8 m/s^2. Deceleration is about 100 m/s^2 when it hit the bottom of the wave. So total force is.. you do the math.. 1,000,000 N or 200,000 pounds.

Now I am sure Catalina has significant design margins.. could be a factor of 5. So it seems, it is not very hard to get to 1,000,000 pounds of force.

However, again I must point out that Brents number of millions of pounds is not incorrect. But your interpretation of it seems to be incorrect.
Bryce

Last edited by BryceGTX; 08-08-2013 at 02:07 AM.
  #459  
Old 08-08-2013
grumpy old man
 
Join Date: Apr 2011
Posts: 3,649
Thanks: 1
Thanked 74 Times in 70 Posts
Rep Power: 4
bobperry will become famous soon enough
Re: Pros and cons of steel sailboats

"I agree, if we would apply BS's logic to cars we would all be driving Sherman tanks."

Maybe. I was thinking more like NY Checker cabs.
bubb2 likes this.
__________________
Please visit my blog. It's fun to read.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Bob's Blog ....

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


Please also visit my new web site
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
  #460  
Old 08-08-2013
Senior Member
 
Join Date: Nov 2002
Location: New York
Posts: 5,569
Thanks: 0
Thanked 14 Times in 14 Posts
Rep Power: 14
bubb2 has a spectacular aura about bubb2 has a spectacular aura about bubb2 has a spectacular aura about
Re: Pros and cons of steel sailboats

Quote:
Originally Posted by bobperry View Post
"I agree, if we would apply BS's logic to cars we would all be driving Sherman tanks."

Maybe. I was thinking more like NY Checker cabs.


My youngest son just got his learners permit. He has visions of a Ferrari as a first car. Dad is thinking Checker cab.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Never Forgotten

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Closed Thread


Currently Active Users Viewing This Thread: 5 (1 members and 4 guests)
jackrve
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Hunter 36 Pros and Cons? turfguy Hunter 15 3 Weeks Ago 05:08 PM
C & C 24 pros and cons chuckg Boat Review and Purchase Forum 11 04-06-2012 12:45 AM
Pros and Cons of Catalina 350?? turfguy C350 6 10-16-2009 05:17 PM
Watermakers—Pros and Cons Tom Wood Cruising Articles 0 06-11-2002 08:00 PM
Steel Hulls—Pros and Cons Sue & Larry Buying a Boat Articles 0 09-12-2001 08:00 PM


All times are GMT -4. The time now is 06:26 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.