How to repair cracks in Livingston hull

[kinaiahi61]

Aloha,
I am about to fix my boat for the second time (2001 14' Livingston twin hull) . These photos are prior to the last fix. I glassed 2 layers on of 1708 nytex. It lasted for a bit, but I was out on a rough day and had to fly back to the harbor. That did it. It cracked all where it was repaired and then some. I was planning on doing a couple of layers of 1708 inside and a couple outside. Should I go all the way over the middle hump and tie into the floors or just do around the corners. Since the crack is all the way through on the 90 degree of the hull should it be ground all the way out? Should I gelcoat or paint the outside. I will be using laminating resin and 1708 nytex. Any input is appreciated. This boat is run hard so the best, strongest fix would be ideal.

 

[Woodonglass]

Re: How to repair cracks in Livingston hull

Yeah, for sure you're gunna need to do the inside. The location of the crack makes it a bit more complicated especially doing it laying on your back. Any chance you can do the inside and then flip the hull to do the bottom?

 

[a1964rn]

Re: How to repair cracks in Livingston hull

The best and strongest fix would be to use epoxy. You can get pigment at US Composites to color the epoxy so you can possibly match the color. Good Luck!

http://www.c-cyachts.com/images/com...91-785DC064755F/16cf4_Adv_of_Epoxy_v_Poly.pdf

 

[Woodonglass]

Re: How to repair cracks in Livingston hull

Epoxy is good but...Not needed for this repair IF you will be laying glass both on the inside of the hull and the outside. If you use epoxy on the outside you will not be able to apply Gelcoat.

 

[a1964rn]

Re: How to repair cracks in Livingston hull

This boat is run hard so the best, strongest fix would be ideal.

The best, strongest fix is epoxy. Might not be the cheapest...

 

[ondarvr]

Re: How to repair cracks in Livingston hull

I have a couple of Livingstons, they tend to be rather thin. On one I completely re-glassed both hulls with 1708, some spots have several layers. The other is leaning up against my shop needing the same type of repairs.

I would do the inside and probably cover the entire top of the hump if it appears to be at all thin.

 

[kinaiahi61]

Re: How to repair cracks in Livingston hull

Thanks for all the replies. I plan on grinding the inside, laying the glass then flipping the boat after to do the bottom. Did the whole bottom last time upside down. That was the first and the last! Sucks cause the tunas are around and my boat is down again.

 

[Woodonglass]

Re: How to repair cracks in Livingston hull

Gelcoat or Paint on the outside?

 

[kinaiahi61]

Re: How to repair cracks in Livingston hull

What are the advantages/disadvantages of each?

 

[Woodonglass]

Re: How to repair cracks in Livingston hull

Gelcoat is a lot more durable. It's a bit more difficult to apply but since it's on the very bottom of the boat and you're flippin her, I'd strongly suggest you go with Gelcoat. Especially since you say the boat is "Rode Hard"! You can Spray it or Roll it but Rolling it is NOT that easy to do with good results. YD and ondarvr are our local Gelcoat experts so they can give you all the advice on how to do that. I like paint but NOT for your boat. Your lams on the inside should be 2 layers of 1.5 oz CSM a layer of 1708 another layer or CSM and a final Layer of 1708. Outside should be Two layers of CSM a layer of 1708 and a final layer of CSM. that should give you the strength you need for it to last. Not sure where you're located but www.uscomposites.com is a great resource for supplies on the east coast. Shipping can be a bit pricey to get it to the West Coast. Lots of suppliers on the West Coast.

 

[kinaiahi61]

Re: How to repair cracks in Livingston hull

Located on the island of Kauai in Hawaii. Resin is $55 a gallon and 1708 is close to $20 a yd. shipping to Hawaii is usually not worth it so we need to just pay the price. What weight CSM would you recommend? Thanks for the help. Aloha

 

[kinaiahi61]

Re: How to repair cracks in Livingston hull

Sorry, saw you put 1.5 oz CSM. THANKS

 

[kinaiahi61]

Re: How to repair cracks in Livingston hull

Just curious on the CSM. Is the backing on the knitex CSM? Does this add more strength or just better tooth for the knitex to grab? Also do I need to grind away everywhere that I'm glassing with 36 grit or would roughing with a sander and 80 grit ok? Thanks again for the knowledge!

 

[ondarvr]

Re: How to repair cracks in Livingston hull

You can skip most of the the CSM, it adds little strength and sucks up resin. Use one layer to start the layup and just use 1708 after that. This will keep the cost down.


36 grit is better than 80.

 

[Yacht Dr.]

Re: How to repair cracks in Livingston hull

Just curious on the CSM. Is the backing on the knitex CSM? Does this add more strength or just better tooth for the knitex to grab? Also do I need to grind away everywhere that I'm glassing with 36 grit or would roughing with a sander and 80 grit ok? Thanks again for the knowledge!

Rougher the better .. Yes you need to get to raw glass before you glass your new ..

80 grit is fine for topcoat gel .. not enough for glassing ..

The CSM is for Bonding and workability .. you Need this IMHO ..

YD.

 

[kinaiahi61]

Re: How to repair cracks in Livingston hull

Thanks for the replies. What is IMHO?

 

[matt167]

Re: How to repair cracks in Livingston hull

In My Humble Opinion/ In My Honest opinion

 

[kinaiahi61]

Re: How to repair cracks in Livingston hull

Any advice on joints of fabric. From what I've read long triangle joints are better than butt and overlaps, is this true? Also is there a correct way to lay the knitex in relation to layering and in relation to the weak spot or crack? Should the direction be changed after the first layer to add more directional strength? Or since its stitched just layer the same direction? Thanks

 

[ondarvr]

Re: How to repair cracks in Livingston hull

Your 1708 will give the best orientation for the fibers, you could lay one the other direction if you wanted, it may help a little.

The first layer of CSM helps, the rest add nothing to the bond strength. If doing multiple layers at one time the mat stitched to the fabric is sufficient (they designed it to work that way). The final mat does nothing but possibly give you a better surface profile depending on what you want it to look like.

If the resin was cheap the extra mat wouldn’t make a difference, wouldn’t help much, but wouldn’t hurt either.

 

[Woodonglass]

Re: How to repair cracks in Livingston hull

I suggest the final layer of CSM to Hide the woven look of the CSM showing on the outside of the hull. Of course by the time you use fairing material it may not be an issue. It will use more resin and as ondarvr not add much to the strength so it's totally up to you. I DO think that applying CSM as the initial layer to bare glass prior to the 1708 gives you a much better bond than the thin layer of CSM that is stitched to the CSM. Again Just my opinion and ondarvr has MUCH more experience than I do. Your boat, your decision. Either way will work just fine an yield acceptable results.