Reply
 
Thread Tools Display Modes
 
Old 01-31-2016, 03:44 PM   #1
Guru
 
City: Seaford Va on Poquoson River, VA
Country: United States
Vessel Name: Old Glory
Vessel Model: 1970 Egg Harbor 37 extended salon model
Join Date: Jan 2016
Posts: 1,299
High density polyurethane plastic frames - ribs

I like this idea a lot. It solves the rotting cracking oak frames problem.
The worst part of my own hull rebuild was dealing with bent frames. The planks were not any problem. Infact I was able to reuse all the mahogany planking. Did use new bronze screws.

__________________
Advertisement

sdowney717 is offline   Reply With Quote
Old 01-31-2016, 04:17 PM   #2
Senior Member
 
Old deckhand's Avatar
 
City: Sitka
Country: Same
Vessel Model: Transpacific Marine Eagle 32
Join Date: Dec 2014
Posts: 494
Cool
__________________

Old deckhand is online now   Reply With Quote
Old 01-31-2016, 05:26 PM   #3
Guru
 
Scary's Avatar
 
City: Walnut Grove Ca
Country: USA
Vessel Name: Cary'D Away
Vessel Model: Hatteras 48 LRC
Join Date: Apr 2012
Posts: 884
How strong do you think the foam is

Laminated oak ribs are way stronger than foam . the ribs do more than keep the planks fair, they also distribute the load over many planks . I don't think I would go this route. It is just too easy to cold bend strips in place glued with epoxy.
Scary is offline   Reply With Quote
Old 01-31-2016, 08:42 PM   #4
Guru
 
City: Seaford Va on Poquoson River, VA
Country: United States
Vessel Name: Old Glory
Vessel Model: 1970 Egg Harbor 37 extended salon model
Join Date: Jan 2016
Posts: 1,299
It is extremely strong this plastic framing.
HDMW polyethylene. I can tell he likes the stuff.



sdowney717 is offline   Reply With Quote
Old 02-11-2016, 10:45 AM   #5
Senior Member
 
Old deckhand's Avatar
 
City: Sitka
Country: Same
Vessel Model: Transpacific Marine Eagle 32
Join Date: Dec 2014
Posts: 494
Thanks for videos.
Old deckhand is online now   Reply With Quote
Old 06-21-2016, 11:47 PM   #6
Guru
 
City: Between Oregon and Alaska
Country: US
Vessel Name: Charlie Harper
Vessel Model: Wheeler Shipyard 83'
Join Date: Jun 2016
Posts: 629
I am a former shipwright. Without going into how we did it in the old days, laminated oak strips, epoxied are probably the easiest for owners to do and have a solid hull. I would check with a couple good wood surveyors before using plastic. The plastic could make that part of the hull stiffer and cause other parts to work too much in a sea. Plastic could shatter, fasteners pull out and so on.
Lepke is offline   Reply With Quote
Old 03-24-2017, 12:24 PM   #7
Veteran Member
 
Lady soft's Avatar
 
City: Trosa
Country: Sweden
Join Date: Mar 2017
Posts: 42
I am not an expert, but I believe that mixing materials like this, is no good, because wood is a live material, and plastic is not, so when the wood actually getting its strange,from being able to move with the element it is forced to work against, like waves. The plastic will not. So I am convinced, this will cause stress to the wood, exactly were the plastic is attached. If you look at the way Coronet built their boats. The wooden interior was never attached directly to the plastic hull. They used a frame.
Lady soft is offline   Reply With Quote
Old 05-17-2017, 11:26 PM   #8
Senior Member
 
GoneFarrell's Avatar
 
City: La Conner, WA
Country: USA
Vessel Name: Imagine
Vessel Model: Farrell 34
Join Date: Oct 2015
Posts: 176
I used to be an expert, 30+ years mechanical engineer, designed all sorts of bending/cantilevered things.

IMHO, UHMW is way less stiff vs. oak/oak laminate. That means the boat will likely flex/work more for a given load.

Data: UHMW, E (modulus of elasticity) 110,000 psi
Oak, E, about 10x that above.

And yeah, I've made all kinds of stuff out of both. Stay with oak. UHMW is amazing stuff, but it is not structural grade material, not for my boat!
GoneFarrell is offline   Reply With Quote
Old 05-17-2017, 11:37 PM   #9
Guru
 
Simi 60's Avatar
 
City: Queensland
Country: Australia
Vessel Model: Milkraft 60 converted trawler
Join Date: Jul 2016
Posts: 753
Quote:
Originally Posted by Lady soft View Post
I am not an expert, but I believe that mixing materials like this, is no good, because wood is a live material, and plastic is not, so when the wood actually getting its strange,from being able to move with the element it is forced to work against, like waves. The plastic will not. So I am convinced, this will cause stress to the wood, exactly were the plastic is attached. If you look at the way Coronet built their boats. The wooden interior was never attached directly to the plastic hull. They used a frame.
Can't say I agree with you there.
How do you explain strip planked boats where the core is timber, usually western red cedar or balsa covered in a fiber reinforced plastic skin?
Simi 60 is online now   Reply With Quote
Old 05-18-2017, 12:08 AM   #10
Senior Member
 
GoneFarrell's Avatar
 
City: La Conner, WA
Country: USA
Vessel Name: Imagine
Vessel Model: Farrell 34
Join Date: Oct 2015
Posts: 176
Simi,
I can explain it with a formula that has served me and my customers for over 30 years: I=B*H^3/12.

The FRP skin you reference is on the outer fibers of the "beam" and that is a cubic with distance from the neutral axis effect. So the FRP far from the neutral axis does a great job of adding stiffness. As does the outer strip planking, which is stiffer than UHMW, it is efficiently used because it is far from the neutral axis.

With a simple UHMW beam, there is no stiff material far from the neutral axis, hence it cannot be as stiff and strong.
GoneFarrell is offline   Reply With Quote
Old 05-29-2017, 10:10 PM   #11
Veteran Member
 
Right rudder's Avatar
 
City: Libertyville
Country: USA
Join Date: Jan 2014
Posts: 50
Shipwright Sauzed used this on a working boat. A fishing boat to be exact, one that he did the same repair to the starboard side two years prior to the YouTube take listed above.

I have known a few guys that make their living by fishing and I find that like any self employed working man that they (most of them anyway) know the value of a dollar, or as one told me " don't say dollar....say work credit". He went on to explain that every time he contemplates divesting of some of his "work credits" it goes through his mind just how hard he works to accumulate it in the first place and it causes him to scrutinize just a little closer the true cost of outlays to his business.

The Owner of the workboat in question is apparently satisfied with the pervious repairs to the point of doing the same thing to the port side.

A rib with a little flex
won't draw water
won't conduct electricity
won't grow mildew
won't rot
What's not to like?

Let's all check back in here in a hundred years and see what's going on.

__________________

Right rudder is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not 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 Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 12:45 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012