bulkhead/beam delamination

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meholden

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Topic: bulkhead/beam delamination
Posted: 11 June 2007 at 1:32am

I have been looking at a laser to buy. I have a question about one I looked at today, hope someone is reading and knows about this.

The structural beam (near the mast support) has cracked loose from the hull. Behind the pockets on both sides, and under the seat cushion as well on port. The hull on the outside has a very mild wave where I think the chainplate support rod is tabbed in. Three questions:

Is this a common problem?

Is this expensive or necessary to fix?

Can you inspect the chainplate reinforcing rod attachment to the hull without cutting the liner?

I attached a picture showing the general area, and a sketch as I remember and to the best of my (not good) ability to draw.

Thanks for any responses,

-Mike

Bill Brock View Drop Down

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Posted: 12 June 2007 at 7:44pm

Hello Mike,

On my boat the liner (which is the structural beam you refer to) has also separated from the hull under the mast support and in the liner just aft (you may want to pull up the floor boards next to the table and check that area also). I know of one other boat that has also experienced this problem. I know of no easy way to completely repair it. In some areas on my boat the gap between the hull and liner is probably 3/16" which is too wide to just inject resin into the slot. Putting resin putty in the gap is of little value since it has no real strength in tension or sheer. Even if you could flex the hull to get the liner back in place, I am not sure it would stay over time without increasing the size of the bonding area (between the liner and the hull) that holds the liner in place.

I would also suggest you check the area directly under the mast support for cracks or indications of potential structural failure. The previous owner of my boat had a failure in the liner that supports the mast post. I have completely rebuilt that section of the liner using high-density liquid foam and three layers of kevlar. The repair has worked very well.

As a side note, from this one picture the boat looks clean. The interior looks original with original upholstery. You will be happy the wires for the mast run outside the mast step and through the deck. My wires run through the mast step and I can not keep it from leaking.

I hope this helps. The Laser 28 is a fun boat sail.

Bill

Bill Brock View Drop Down

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Posted: 12 September 2008 at 1:13pm

Hi Guys,

Another owner has contacted me regarding his deck sagging at the mast. A more thorough examination found that the hull liner, which provides structural support for the mast just above the keel, had failed. I know now of at least three people (myself being one) who have experienced the same problem. In my case the wood block that was put inside the liner was apparently exposed to water coming down the mast which, over time, caused it to deteriorate and eventually fail. I would strongly suggest everyone check their boats this Fall to make sure their liner is not beginning to fail in that region. Be sure to look inside the seat compartment adjacent to the mast as well. A potential problem will be indicated by small cracks on the liner directly adjacent to the mast support post.

If you have any cracks around the base of the mast post I would suggest you take immediate action to prevent them from propagating. Failure to correct the problem could lead to total liner failure. As mentioned above, I had to totally rebuilt my liner in that region as it did totally fail. I had to rebuild the liner with cloth and resin. If you can catch it early enough, a total rebuild would not be necessary. I used a high-density liquid foam which I poured into the liner cavity to reinforce the liner and better distribute the mast load to the hull. You mix two chemicals together and they expand and fill the cavity. As best I remember the foam will support somewhere around 300 or more lbs per square inch. I also fabricated a little larger mast support plate for on top of the liner to distribute the load over a wider area. To do this I had to shorten the mast support inside the cabin. If you are not experienced in working with fiberglass I would suggest you have a knowledgeable repair service perform the work. For more information write me at: color=#810081wmabrock@msn.com under the Subject: Laser 28 Liner.

Bill

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meholden Members Profile Send Private Message Find Members Posts Add to Buddy List Rookie Joined: 12 May 2007 Location: United States Status: Offline Points: 19	Post Options Post Reply Quote meholden Report Post Thanks(0) Quote Reply Topic: bulkhead/beam delamination Posted: 11 June 2007 at 1:32am
	Hi I have been looking at a laser to buy. I have a question about one I looked at today, hope someone is reading and knows about this. The structural beam (near the mast support) has cracked loose from the hull. Behind the pockets on both sides, and under the seat cushion as well on port. The hull on the outside has a very mild wave where I think the chainplate support rod is tabbed in. Three questions: Is this a common problem? Is this expensive or necessary to fix? Can you inspect the chainplate reinforcing rod attachment to the hull without cutting the liner? I attached a picture showing the general area, and a sketch as I remember and to the best of my (not good) ability to draw. Thanks for any responses, -Mike

Bill Brock Members Profile Send Private Message Find Members Posts Add to Buddy List Skipper Joined: 08 February 2005 Location: United States Status: Offline Points: 53	Post Options Post Reply Quote Bill Brock Report Post Thanks(0) Quote Reply Posted: 12 June 2007 at 7:44pm
	Hello Mike, On my boat the liner (which is the structural beam you refer to) has also separated from the hull under the mast support and in the liner just aft (you may want to pull up the floor boards next to the table and check that area also). I know of one other boat that has also experienced this problem. I know of no easy way to completely repair it. In some areas on my boat the gap between the hull and liner is probably 3/16" which is too wide to just inject resin into the slot. Putting resin putty in the gap is of little value since it has no real strength in tension or sheer. Even if you could flex the hull to get the liner back in place, I am not sure it would stay over time without increasing the size of the bonding area (between the liner and the hull) that holds the liner in place. I would also suggest you check the area directly under the mast support for cracks or indications of potential structural failure. The previous owner of my boat had a failure in the liner that supports the mast post. I have completely rebuilt that section of the liner using high-density liquid foam and three layers of kevlar. The repair has worked very well. As a side note, from this one picture the boat looks clean. The interior looks original with original upholstery. You will be happy the wires for the mast run outside the mast step and through the deck. My wires run through the mast step and I can not keep it from leaking. I hope this helps. The Laser 28 is a fun boat sail. Bill

Bill Brock Members Profile Send Private Message Find Members Posts Add to Buddy List Skipper Joined: 08 February 2005 Location: United States Status: Offline Points: 53	Post Options Post Reply Quote Bill Brock Report Post Thanks(0) Quote Reply Posted: 12 September 2008 at 1:13pm
	Hi Guys, Another owner has contacted me regarding his deck sagging at the mast. A more thorough examination found that the hull liner, which provides structural support for the mast just above the keel, had failed. I know now of at least three people (myself being one) who have experienced the same problem. In my case the wood block that was put inside the liner was apparently exposed to water coming down the mast which, over time, caused it to deteriorate and eventually fail. I would strongly suggest everyone check their boats this Fall to make sure their liner is not beginning to fail in that region. Be sure to look inside the seat compartment adjacent to the mast as well. A potential problem will be indicated by small cracks on the liner directly adjacent to the mast support post. If you have any cracks around the base of the mast post I would suggest you take immediate action to prevent them from propagating. Failure to correct the problem could lead to total liner failure. As mentioned above, I had to totally rebuilt my liner in that region as it did totally fail. I had to rebuild the liner with cloth and resin. If you can catch it early enough, a total rebuild would not be necessary. I used a high-density liquid foam which I poured into the liner cavity to reinforce the liner and better distribute the mast load to the hull. You mix two chemicals together and they expand and fill the cavity. As best I remember the foam will support somewhere around 300 or more lbs per square inch. I also fabricated a little larger mast support plate for on top of the liner to distribute the load over a wider area. To do this I had to shorten the mast support inside the cabin. If you are not experienced in working with fiberglass I would suggest you have a knowledgeable repair service perform the work. For more information write me at: color=#810081wmabrock@msn.com under the Subject: Laser 28 Liner. Bill