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PostPosted: Tue Jun 25, 2013 10:56 am 
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I have a 1978 Hobie 16, that I did some restoration work on 5 years ago.

Last week it was smashed up against a rock and a 6" by 10" section on the side was damaged. About 1/2 of the damage is on the hull side directly under the deck, and the other 1/2 is on the deck. Although the damage did not puncture the hull at all, it is significantly weaker in that section than the rest of the boat when you press on it. (I will be adding pictures later tonight)

I am looking for some advice on how I should do the repair.

Since the boat has been repainted to its original color, I do not need or want to deal with any gel coat repair, I will just repair the boat and paint over that section with my leftover paint.

I have been told that epoxy resin is much stronger than polyester resin, and I think that is the direction I am going to go. I have also been told that Marin Tex Epoxy putty may be a great solution for this issue? What are your experiences with epoxy resign/fiberglass vs the Marine Tex.

I plan on taking a grinder and grinding off the cracked gel coat near the damaged areas down to solid fiberglass (should I do the whole 6" x 10" section or just where the cracks are?) and then feathering it in, then using epoxy resin and fiberglass sheet, or just epoxy putty, build up the area and sand it smooth. (I will leave it ugly for the rest of the season, and then paint it before I put the boat away)

What are your thoughts on this repair, any information would be greatly appreciated.


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PostPosted: Wed Jun 26, 2013 7:09 pm 
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Joined: Mon Jul 14, 2003 7:11 pm
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Location: Detroit, MI
A 6" x 10" repair that extends through the deck lip requires a professional repair. The deck lip is a structural element. You will be appalled at how far back you have to go to get to good, solid fiberglass before the rebuilding starts. Pictures would help to make a more precise diagnosis.

Marine-Tex is not appropriate in this instance.

You're at that juncture where it will cost nearly as much to repair this hull as it would to replace it with another used hull. Even if you do fix it, you'll still have a 35 year old hull.

Find a cheap boat with solid hulls, part it out and use one of the hulls - maybe both - to replace your existing.


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PostPosted: Thu Jun 27, 2013 5:48 am 
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I am definitly aware that finding a replacement hull is the best way to go. However, for the handfull of times I use the boat each year, I can not warrant that effort and money and there are not many for sale in Buffalo. I do not race the boat, I only use it on nice weekends. I honestly beleive the boat is structurally sound to sail even with the damage, however I am going to repair it for safety.

I will post pictures this afternoon.


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PostPosted: Fri Jun 28, 2013 2:52 pm 
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Here are some pictures of the damage. It does not show up to well on camera though.

http://tinypic.com/r/1zyu9af/5

http://tinypic.com/r/2w59185/5


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PostPosted: Fri Jun 28, 2013 3:08 pm 
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Location: Detroit, MI
Image
Image

That's between the front pylon attachment and the shroud anchor - both high stress areas. The hull-deck seam is broken and the outer glass (at least) in the hull is torn. It needs to be fixed right, and based on your other comments (Marine-Tex), you're not the person to do it, IMHO. This isn't an easy nor an inexpensive repair.


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PostPosted: Sat Jun 29, 2013 7:12 am 
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Joined: Mon May 24, 2004 10:33 am
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Location: Clinton, Mississippi
FYI....I have a friend who had similar, but not nearly as extensive, damage from collision by another boat. It was professionally repaired from the outside, but showed back up after only a year or so......just too much stress in that area.

MarineTex certainly is not the answer. Maybe make a port and use a bunch of glass/epoxy both inside and out? Not sure you could access the inside good even with a port because of the pylon.

On the other hand, if you only sail a few times a year, and if you're not going offshore or in freezing conditions, and if you're willing to suffer the consequences when the hull breaks in half and sinks....then go for it!

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Jerome Vaughan
Hobie 16


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PostPosted: Sat Jun 29, 2013 9:29 am 
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After everything I have heard about Marine Tex - I will not be using that product, It was just something I have never heard of before, and wanted to get an opinion on.

I am aware this is a very high stress location on the boat, so I will be making a strong repair. I plan on using West Systems Epoxy, and fiberglass matting. I will be grinding down the area and feathering it in (Probably around a 15 - 1 bevel angle). Using multiple layers of fiberglass matting in the epoxy. I plan to go over the hull side, under the lip, around the edge, and onto the deck with one continuous piece of matting for increased strength.

There is no way for me to access the interior in order to add epoxy to the inside of the repair, and I will not be cutting a hole and putting a port in.



All your feedback is great. Thanks


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PostPosted: Fri Jul 05, 2013 6:17 am 
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I have been working on this repair project a few nights after work and it is almost complete. Here is an update of what I have done.

Supplies:
West System 105 Epoxy
West System 406 Slow Hardner
West System 404 High Density Filler
West System Fiberglass Cloth
Paint Brush
Mixing Sticks/tubs
Sand Paper
Orbital Sander
Plastic Spreader
Window Screening
Silicone Spray
Acetone - Throughout Cleaning was performed between each step.
Blue Painters Tape

1) Damage
After being smashed up against a large rock by a few waves, the uper side of the hull and the top of the deck near the front pylon had impact damage.
Top View
Image
Side View
Image

2) Preparing the Surface
In order to determine the actual extent of damage, and to start the repair, the area needed to be ground down. Using a 4" angle grinder the damaged area was ground down past the gel coat, and until only good fiberglass was left. The area was then feathered in to the rest of the hull providing a good amount of un damaged fiberglass to bond to. As you can see, there was 1 main crack along the top, and 1 point damage spot that extended to the core (no core damage). Along with some cracking along the side.
Top View
Image
Side View
Image

3) Fiberglass Cloth
Sections of fiberglass cloth were cut out to match the damaged area. A few small sections were used to fill in the deeper damaged areas, then larger sections were used to cover up the cracks fully with 1 inch on each side of the crack, three strips were used to add support under the deck/hull lip, and finally a large section, the size of the entire ground down area, was used to cover the top, go over the edge, tucked up inside the deck/hull lip, and down the side.

4) Fiberglass Application
Epoxy and Hardner were mixed together and high density filler was added until the mixture became a ketchup like consistancy. Using a small paint brush, the mixture was applied to the boat, and the fiberglass cloth was applied/saturated/excess removed in layers until the final large piece was applied.
Image

5) Sanding
The surface left from the fiberglass application was not the smoothest, so a orbital sander and regular sand paper were used to smooth out the surface.
Image

6) Top Coat
Epoxy and Hardner were mixed together and high density filler was added until the mixture became a penut butter like consistancy. Using a plastic spreader, this was applied liberally over the repair and feathered into the boat. Care was taken to match the final shape closely with the hull.
Image

7) Sanding
Again, the surface was not the smoothest and did not match the boat perfectly, so an orbital sander and regular sand paper were used to sand down the top coat until it matched the boats profile perfectly.
Image

8) Non Skid Pattern
Since the non skid pattern was eliminated from the area where the repair was done, it needed to be fixed to match the boat. A rectangular section of the nonskid pattern around the repair was taped off and sanded away. Epoxy and Hardner were mixed together and high density filler was added until the mixture became a ketchup like consistancy and it was brushed on over the area. After approximatly 40 minutes the area was curing and the expoxy mixture was solid, but still soft. A section of window screening was coated with silicone spray (for a release agent) and the screening was pressed into the area, then removed. This left a very similar non skid pattern as the original boat.
Image
Image

9) Not Done Yet - The area lacking the non skid pattern needs to have filler putty applied to fill in any porus areas left by the epoxy. This is necessary in order to get a good paint job.

10) Not Done Yet - The area needs to be primed before it is put in sunlight or used on the water.

11) Not Done Yet - At the end of the season I will be repainting the entire hull side/top with left over 2 part polyurathane paint from when I painted it years ago.

Only time will tell how good this repair is, however I am currently happy with it. The repair seems to be very strong, possibly even stronger than the orignal boat. The repair also looks very good, it will not be too noticable once painted.


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PostPosted: Fri Jul 05, 2013 10:03 am 
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Joined: Sat Oct 29, 2011 4:27 pm
Posts: 556
Location: Central Oregon
Nice work! May she sail many more years!
Liked your window screen non skid!
Keep us updated!

_________________
1980 H16
1997 Wave


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PostPosted: Sun Sep 21, 2014 10:49 pm 
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Joined: Sun Sep 21, 2014 10:26 pm
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Location: Sparta, NJ
This is really great work done....

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New Jersey Deck Builder


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