Be vicious with it !

1, clean out all cracked gelcoat; remove all the fibers that look like they have dirt/grime in them; remove any soggy glass matt (it probably won't really dry properly). Basically remove all the old/damaged areas and make sure you have a clean area to repair. This could mean removing some of the Keel line and having a "Slot" down the middle of the boat.

2, Make sure everything is clean and dry - VERY VERY important - you can use an Acetone to really clean it and a hair dryer to make sure it is dry

3, If you have an empty slot (if not go to 8) you need to build a backing plate (Thin Balsa can be good for this and then put some string thru it so you can pull it snug to the INSIDE of the hulls by putting your mold thru the slot you have made by cleaning out the old/damaged area and then pulling back snug (this is where the second pair of hands becomes useful !

4, While someone holds the string (and so mold) snug to the inside of the hull, apply glass mat and gellcoat to the hole/slot you have made; Ideally you want to get at least one layer of mat on the inside of the hull - Tip:
Stick the Matt (and gelcoat) to the balsa/cardboard; then put the sting thru and then put this inside the hull and pull it back so the matt sticks to the hull inside. Now while "String pulling mate" holds the string you need to gaffa tape the sides of the hull into the right position so that then the matt sticks it will hold the hull in the correct shape.


5 Let this cure; you now should have a hole that you can fill up and return the hull to the right shape

6, At this point depending on the side of the void left :

7 Big void - long or wide; I would fill this with gelcoat mixed with chopped strand mat (very hard when it goes off) and then move onto 8.

8 small - Just use filler

9 Top tip 2; when you are getting close to the correct level/shape of the hull; use "grease proof" cooking paper as a outside skin as this will allow you to get a good finish before you need to start standing

10 once you have filled the hole(s) up you need to sand back to the right level; use 400;600 and 1000 wet and dry and then polish if required


So you will need

Acetone (check which one) - some melt gelcoat
Gelcoat of the appropriate colour
Glass mat (depending on the scale of the repair)
Mixing pots for gelcoat - paper are best; just throw away after Mixing sticks - I use wooden sticks you get for coffee at Starbucks and the like - might need a spatula for gelcoat when mixed with chopped strand glass.

That's about it.

Greetings,

I need some "how to" advice. I have a SC-17 with a very thin two inch crack in a hull. When I push on the crack, the hull gives a little more than other areas. The crack is located on the inner face of the hull, four inches infront of the forward beam and six inches down from the top on the hull. I do not know if the crack penetrates all the way through the fiberglass. The previous owner painted the hulls with Dupont Imron.

If I were to repair the crack back to its original strength, what do I need to do? The SC-17 does not have any inspection ports.

Hey royaluser, I too have a Supercat 17, incredible little boat… the best thing you can do is go to http://aquarius-sail.com/default/
From there, go to the owners forum, then to the Technical Forum section. Post your problem in as much detail as possible. This is the forum hosted by the Builder of the Supercat and ARC catamarans. They know exactly what materials are in the boat, how they structurally work together, and how it needs to be repaired. Matt and Tom Haberman are very responsive…and don’t be surprised if the Supercat designer (Bill Roberts) doesn’t respond as well.

While you can get a lot of generic advice here on the Catsailor forum about repairing catamarans in general …a repair technique that has worked on a Hobie or Performance brand cat may not be satisfactory on your Supercat. The location of the crack you are talking about could become a very serious structural issue, and needs to be addressed before the boat is put into use.

When you can get free expert repair advice right from the builder why would you want to go anywhere else? Customer service is one of the many benefits of owning a Supercat/ARC catamaran. It doesn’t matter if you bought a new ARC catamaran last week or a 25 year old used Supercat from your local newspaper, they will support you with specific information and parts.


Personally (even with 39 years of experience in fiberglass/composites) I would not initiate any repair to my SC 17 before contacting Matt or Tom for their insight on the matter.
Each structure is different. …

Regards,
Bob

How so Jake? It was not meant to be insulting at all...just send him where he can get specific information on his boat...

Regards,
Bob

Krikey, Jake! What the heck did you do to that F18? Was that due to some slick move you learned on tacticat?

That's a nasty scratch/crack....