Hobie Cat Forums

It is currently Tue Aug 19, 2014 10:27 pm

All times are UTC - 8 hours [ DST ]




Post new topic Reply to topic  [ 19 posts ]  Go to page Previous  1, 2
Author Message
PostPosted: Thu Jan 30, 2014 10:55 am 
Offline
Site Rank - Deck Hand

Joined: Sat Nov 23, 2013 12:52 am
Posts: 7
Very nice work for such a tough place to access. I just wanted to add a suggestion for those doing internal hull repairs regarding material choices. I have experimented over the years with layups for molded RC racing planes to creat "hulls" with stiff areas blended to impact resistant zones yet preventing twist and stress failures. While carbon fiber is great for areas you want to be as stiff as steel, it can create stress points at its edges and increase the chance of failure. Blends of S glass carbon and kevlar are available and give you options that are great for hulls. Kevlar is hard to cut but manageable. It provides a highly flexable patch yet with extremely high impact resistant. It is very light as well. Glass is great for bonding and resin up take. For the sides of hulls a blend of the three would likely be superiour to a hard spar. http://shop.fiberglasshawaii.com/ This is just one source of many outlets for fabric mixtures. Your repair above was great for a section that no flex can occur at and your tapering of the carbon thickness is the right idea to avoid focusing stress. If you do use a solid spar I would add a bit of kevlar under it to spread the stress to the hull.
Cheers, Steve


Top
 Profile  
 
PostPosted: Thu Jan 30, 2014 11:07 am 
Offline
Site Rank - Old Salt

Joined: Mon May 09, 2005 10:25 am
Posts: 2549
Location: Jersey Shore
Thanks for the positive feedback. This repair/reinforcement is a bit of uncharted territory for me. Minimizing edge stress concentrations was definitely a concern and the reason for generously overlapped patches. If I go with the reinforcing stringers/spars I will likewise use a tapered design where the thickness reduces at the ends in order to minimize stress concentrations.

sm


Top
 Profile  
 
PostPosted: Sun Jun 15, 2014 1:00 am 
Offline
Site Rank - Deck Hand

Joined: Fri Apr 19, 2013 2:15 pm
Posts: 2
Srm

Thanks for sharing your hull reinforcement work.

I'm considering doing the same for my 1983 hulls. I'm seeing some hairline cracks in the gelcoat forward of the front cross beams. They are not redline hulls.

Last year, I added the extra chainplates, and repaired a large deck delamination in the port hull aft of the board trunk. Delamination repair looks ugly, but the deck is stiff again. I was also thinking about adding deck ports here, but reinforcing the rim with carbon fiber.

How many yards of carbon tape and fabric did you end up using?

RR


Top
 Profile  
 
PostPosted: Mon Jun 16, 2014 12:36 pm 
Offline
Site Rank - Old Salt

Joined: Mon May 09, 2005 10:25 am
Posts: 2549
Location: Jersey Shore
I think I ended up using about 1 yard of 50" wide fabric, 2.5 yards of 6" wide tape, and 16 oz of resin.

sm


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 19 posts ]  Go to page Previous  1, 2

All times are UTC - 8 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group