Pearson 36 hull concavity - Page 2 - SailNet Community
 6Likes
Reply
 
LinkBack Thread Tools
post #11 of 15 Old 06-22-2017
Less Senior Senior Member
 
Join Date: May 2011
Location: Bangor, Maine
Posts: 1,442
Thanks: 39
Thanked 50 Times in 50 Posts
Rep Power: 9
 
Re: Pearson 36 hull concavity

Quote:
Originally Posted by RichH View Post
M - you don't sail it when/while its incorrectly blocked, incorrect blocking is the usual cause of the buckling in such Pearsons. When free floating, the forces onto the hull will be approximately equal.

If the boat was stored/blocked incorrectly for long term or repetitive 'bad' blocking, indeed the hull may have taken a permanent 'set' - but usually rarely so. My suggestion to re-block the boat would be ~prove that the condition was only temporary - due to the undue forces imposed by the probable bad blocking job, and not permanent. ;-)

FWIW - the 'real' problem with most Pearsons of this vintage is zillions of cosmetic (non-structural) osmotic blisters in the underwater gel-coat layer, sometimes superficially into the matting layer ... not a big deal.
If I'm reading correctly, the OP is saying the boat has been in the water 'a few years' and is now in a transport sling. Help me understand how re-blocking would help in this situation? Are you saying that the transport sling may be 'twisting' the boat and causing this?

Ocean- that which covers 3/4 of a world made for man, who has no gills.
seaner97 is offline  
Sponsored Links
Advertisement
 
post #12 of 15 Old 06-22-2017
Senior Member
 
RichH's Avatar
 
Join Date: Jul 2000
Location: Pennsylvania
Posts: 5,021
Thanks: 54
Thanked 326 Times in 310 Posts
Rep Power: 20
   
Re: Pearson 36 hull concavity

On these 'floppy' Pearsons having the lift straps of the travel lift too close towards the keel and not 'out' towards the ends of the boat can induce the same hull compression; thus, momentary resultant buckling.

If you already owned this boat, Id suggest the installation of 1"x1" hat-shaped fiberglass axial stringers along the inside of the hull - mid way to the waterline and parallel to the keel. This is/was commonly done by those who fanatically raced these P's to dampen down the hull flex when 'hard' and aggressive racing; it also served to stiffen the hull for when blocking, etc. (.... but the 'floor' of the damn ice box had to be cut away so to place the stringer 'under' the ice-box).

Bottom line is if you have a 'bad feeling' about this boat ... trust your instincts and walk away - IMO.

;-)
seaner97 likes this.
RichH is offline  
post #13 of 15 Old 06-22-2017 Thread Starter
Member
 
Mongo's Avatar
 
Join Date: Apr 2009
Location: Seattle
Posts: 47
Thanks: 3
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Re: Pearson 36 hull concavity

Interesting point, I went back and looked at the photos and the strap was aft of concave area, shown roughly as shiny area on photo. Thanks for all the great advice, everyone.
Attached Thumbnails
out of water.jpg  
Mongo is offline  
 
post #14 of 15 Old 06-22-2017
Senior Member
 
RichH's Avatar
 
Join Date: Jul 2000
Location: Pennsylvania
Posts: 5,021
Thanks: 54
Thanked 326 Times in 310 Posts
Rep Power: 20
   
Re: Pearson 36 hull concavity

Quote:
Originally Posted by seaner97 View Post
If I'm reading correctly, the OP is saying the boat has been in the water 'a few years' and is now in a transport sling. Help me understand how re-blocking would help in this situation? Are you saying that the transport sling may be 'twisting' the boat and causing this?
.... a Travel lift with its slings too close the keel will tend to cause the boat to 'hog' .... the weight of the ends will tend to sag downwards as the keel is held firm, relative to the position of 'the ends'.
A same situation would develop when one picks up a floppy thin walled FRG pipe/tube, etc. or vaulting pole by the middle ... the ends sag down.
In thin walled structures this can cause compression on the 'underside' of the pipe/tube/poll (or hull) 'skin'; thus, the propensity to buckling. Buckling is a phenomenon of compression in thin walled, etc.structures; the way to prevent such is to keep the structure in tension ... as would happen with keeping the lift straps towards the ends, the jack stands further apart and away from the keel and placing Vpoppit jack stands at the stern and bow. The other way to prevent is to make hull thicker (stronger vs. compression) and thus better able to resist the potential of buckling.
Uncontrolled buckling in structures is a complex mathematical nightmare where just a few pounds of 'side pressure' against a beam or surface, etc., already in compression, can induce the onset of buckling

hope this helps.
seaner97 likes this.

Last edited by RichH; 06-22-2017 at 02:10 PM.
RichH is offline  
post #15 of 15 Old 06-22-2017
Less Senior Senior Member
 
Join Date: May 2011
Location: Bangor, Maine
Posts: 1,442
Thanks: 39
Thanked 50 Times in 50 Posts
Rep Power: 9
 
Re: Pearson 36 hull concavity

Quote:
Originally Posted by RichH View Post
.... a Travel lift with its slings too close the keel will tend to cause the boat to 'hog' .... the weight of the ends will tend to sag downwards as the keel is held firm, relative to the position of 'the ends'.
A same situation would develop when one picks up a floppy thin walled FRG pipe/tube, etc. or vaulting pole by the middle ... the ends sag down.
In thin walled structures this can cause compression on the 'underside' of the pipe/tube/poll (or hull) 'skin'; thus, the propensity to buckling. Buckling is a phenomenon of compression in thin walled, etc.structures; the way to prevent such is to keep the structure in tension ... as would happen with keeping the lift straps towards the ends, the jack stands further apart and away from the keel and placing Vpoppit jack stands at the stern and bow. The other way to prevent is to make hull thicker (stronger vs. compression) and thus better able to resist the potential of buckling.
Uncontrolled buckling in structures is a complex mathematical nightmare where just a few pounds of 'side pressure' against a beam or surface, etc., already in compression, can induce the onset of buckling

hope this helps.
I got it from your last one, but this is more detailed. Thanks.

Ocean- that which covers 3/4 of a world made for man, who has no gills.
seaner97 is offline  
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
1984 Pearson 34's - cored hull? kprhok Pearson 1 02-21-2016 03:40 PM
Does 1983 Pearson 34 have a cored hull? CapSam Pearson 4 05-21-2015 08:15 AM
Is Hull Cored on 1983 Pearson 34?? CapSam Boat Review and Purchase Forum 6 04-19-2014 03:37 PM
Pearson 26 Hull Number jinjyr General Discussion (sailing related) 2 03-24-2014 08:22 AM
First and new (to us) boat! 1985 Pearson 27 Hull #24 itsaboat General Discussion (sailing related) 13 12-08-2011 07:47 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome