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What causes soft hulls to occur?
http://www.hobie.com/au/en/forums/viewtopic.php?f=14&t=38702		 Page 1 of 1
Author:  ASDASC [ Tue Sep 27, 2011 2:08 pm ]
Post subject:  What causes soft hulls to occur?
OK, so I think it is well understood what happens when they go soft, delamination of the layers. But has anyone tried to understand what causes the layers to delaminate faster in some boats?

Is it more common in Northern boats due to the temperature extremes?
Is it more common on boats that spend the summers moored in the water?
...stored outside?
...stored with moisture (water) in the hulls?
... salt water or fresh water?
...sailed agressively? Sunday driver, gentle life with a passive owner?
any other ideas?

If you have had a boat with soft hulls, please list what contributing factors you think lead to it and let's see if we can find a common thread.

So far my '79 is still solid, but I want to keep it that way!
Author:  srm [ Tue Sep 27, 2011 4:06 pm ]
Post subject:  Re: What causes soft hulls to occur?
Manufacturing defects can cause them. Poor layup quality or inferior materials or construction can result in delam issues.

Also, over flexing, over stressing, or cyclical loading can cause them and are probably some of the most common reasons. Repeatedly sitting or stepping on an area or impact damage (which may not be readily visible at the time of occurrence) can lead to soft spots.

I imagine moisture intrusion could cause or accelerate delam, so keeping the hulls dry would be highly recommended.

sm
Author:  MBounds [ Tue Sep 27, 2011 5:11 pm ]
Post subject:  Re: What causes soft hulls to occur?
srm wrote:
Manufacturing defects can cause them. Poor layup quality or inferior materials or construction can result in delam issues.

That's probably the least common cause - especially with older (pre-'84) Hobies. They were built like tanks and weighed accordingly.

srm wrote:
Also, over flexing, over stressing, or cyclical loading can cause them and are probably some of the most common reasons. Repeatedly sitting or stepping on an area or impact damage (which may not be readily visible at the time of occurrence) can lead to soft spots.

This is by far the leading cause of soft spots in the foredecks of 16s (from stepping repeatedly on them) and the deck area ahead of the rear beam on 17s and 18s (from the skipper's butt landing repeatedly on them).

Water intrusion, freeze/thaw cycles, over-tightening trailer straps, high temperatures, UV exposure all contribute to general laminate breakdown over time.

To make your boat last a long time:
- Don't leave it in the water for any length of time (more than a day or two).
- Drain the water out. Not necessary to get every last drop, but 99% out.
- If you sail in salt water, rinse frequently with fresh water.
- Store it in a garage or storage unit, or under cover. Even a carport is better than out in the open.
- Don't use the foredecks as a step.
- Don't let snow build up on it.
- 17s/21s - put a dollop of antifreeze in the wing tubes over the winter.
- Don't over tighten the trailer straps and don't use straps that go over the hulls.

The boats are made to take an amazing amount of abuse, but they aren't indestructible.
Author:  srm [ Wed Sep 28, 2011 6:41 am ]
Post subject:  Re: What causes soft hulls to occur?
MBounds wrote:
srm wrote:
Manufacturing defects can cause them. Poor layup quality or inferior materials or construction can result in delam issues.

That's probably the least common cause - especially with older (pre-'84) Hobies. They were built like tanks and weighed accordingly.


Maybe, however I still have a bit of a bad taste in my mouth from when my brand new 17 (2007) had one on the deck where it was not properly laid up. The dealer did an ok job of fixing it, but still a bit of a bummer. I've also had this happen on other composite sailing craft (formula windsurf board) where the skin separated from the core after the first couple sails and had to be re-bonded. These types of defects will typically show up very early on, so you're correct in that this would not apply to the OPs 1979 boat.

The more weight they try to suck out of the boat, the more critical the layup becomes and the more potential for these types of defects.

sm
Author:  MBounds [ Wed Sep 28, 2011 7:13 am ]
Post subject:  Re: What causes soft hulls to occur?
The quality of the last batch of 17s was not as good as when Hobie Cat was cranking out hundreds of them a year.

I've had bubbles under the gel coat on the bow and both centerboard springs punched through the layup in the CB trunk, causing massive leaks. I've seen drainplugs holes drilled slightly off, so the housing overhung the transom, centerboard hooks break, holes drilled in the wrong place on crossbeams - just lots of little things that made you think that the people building them had never built them before (which was probably true).

The 2007s were made well before (2004 - 2005) and sat in storage, waiting to be sold. Mine (a 2007) doesn't even have the year engraved on the transoms.

There were similar issues with the run of 18 hulls made last year. Nothing major, just little stuff like forgetting the daggerboard shock cord holes in the deck lip.

16s, on the other hand, have generally had consistent, high quality production - because they've never gone out of production. The collective, unwritten building knowledge has been passed along from one worker to the next.
Author:  srm [ Wed Sep 28, 2011 7:41 am ]
Post subject:  Re: What causes soft hulls to occur?
MBounds wrote:
The quality of the last batch of 17s was not as good as when Hobie Cat was cranking out hundreds of them a year.


You can say that again. I had the same issues...delaminated deck at time of purchase, centerboard trunk split through at the springs, wings with the wrong rivets on the end caps (non-countersunk), crossbar bolt covers the wrong size, wing socket covers that are useless, and the deck lip looks like it was trimmed with a chain saw. Now I have issues with the inner hull skin at the forward crossbar. Kinda makes me wish I had just refurbished my '89 boat and saved about $8k.

I guess when you have to beg and plead for Hobie to build a boat they really don't want to build, this is what you end up with. But I digress...of course I love my Hobie! :roll:

sm
Author:  Sail Revolution [ Wed Sep 28, 2011 8:46 am ]
Post subject:  Re: What causes soft hulls to occur?
Here are a few pics of the last 17 and 20 built at Hobie. This was filmed on an early vid capable cell phone. The song doesn't really fit, it was just something I was listening to at the time, 2004.

Look at around 2 mins for the 17s.

[youtube]http://www.youtube.com/watch?v=v9LlNh-jlvI[/youtube]
Author:  ASDASC [ Thu Sep 29, 2011 5:27 pm ]
Post subject:  Re: What causes soft hulls to occur?
Very cool video, thanks for sharing!

I was pretty impressed by the sail cutting tool. It reminded me of a really big chart plotter.
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