Repair Opinions: Hole in sponson

**Meatbasher** · 10-31-2010, 09:06 PM

Hey guys,

I pulled the carpet out of my project today and found a nice chunk of rot where there is a hole in the starboard sponson. I'm not positive on what my plan of action should be since the other side of the rotten wood is the glass on the bottom of the boat!

Do you typically just tear out what you can and just re-glass over the area? Are you supposed to put wood back in here? I'm a little stumped.

Here is the problem area

Here is the hole

Here is the play by play on my blog....
http://ebkostinger.blogspot.com/2010...t-removal.html

**afr** · 10-31-2010, 09:18 PM

yes you need to take it all out and recore the whole boat

**Meatbasher** · 10-31-2010, 11:10 PM

There is seriously no patch and float trick here?! The rest of the hull is perfect! The transom is solid, bow is good, everything is cool!

I see you own, or work at, a fiberglass repair shop. Not trying to second guess your opinion here but I know there are situations where it's easy to say "yeah re-do the whole thing!" when it's possible to do something different. This boat actually had the whole rear end blown out at one point and the whole boat wasn't re-cored. Shouldn't that be an option this time around?

**samari** · 10-31-2010, 11:47 PM

As AFR said it all needs to be redone correctly. That bulsa is completely rotten, any patch repair would be unsafe.

**Riverman** · 11-01-2010, 12:01 AM

Chet speaks the truth. A complete recore is the only option. This is why they are called "projects"!

**native2** · 11-01-2010, 07:28 AM

You can keep peeling it back till you find good core. Then peel, chip, grind, sand, all the old core out. When all ground out, recore that area. That would be the only half ass method I can think of. But, most of that sponson is probably wet..... I would at least do that whole sponson and carefully inspect the other. It is not as hard as you think. Just time consuming...

**Meatbasher** · 11-01-2010, 02:15 PM

Got it. I'll search around the forum for other re-core threads and see what's involved. I'm having a difficult time wrapping my mind around how you go about grinding out the wood without punching through the fiberglass in the bottom of the boat.

**RobF** · 11-01-2010, 02:31 PM

it is like a sponge, its not like that area is a LITTLE wet, it is rotted. The coarse of action is to keep inspecting until you reach good clean balsa, which by the time you are done will probably mean the entire bottom

**oldskier** · 11-01-2010, 02:53 PM

The positive side is that the boat will be much lighter and stronger when you get all the wet rotted wood out. Both suggestions are correct, you probably will find more rot than solid balsa under the core cover. Since it looks like a tunnel (Ebko Stinger?) you might get lucky and find the other sponson solid and dry, but it ain't likely as wet as that one is. Almost all old balsa cored performance boats are gonna need a core replacement. We all thought OUR'S wouldn't, but we all were wrong.

Ever seen a project that DIDN'T get out of hand?

I'm having a difficult time wrapping my mind around how you go about grinding out the wood without punching through the fiberglass in the bottom of the boat.

You get a 4 1/2 inch angle grinder with a 36 grit disk and you grind the balsa and into the fiberglass until you hit clean fiberglass, then STOP! (We all ground through a few places, patch with a couple of layers of mat.) In a cored boat, the fiberglass outer hull by itself is NOT thick or strong, the fiberglass outer hull along with the 1/2 inch of balsa and the fiberglass inner cover is REALLY thick and strong.

**native2** · 11-01-2010, 03:33 PM

Originally Posted by Meatbasher

Got it. I'll search around the forum for other re-core threads and see what's involved. I'm having a difficult time wrapping my mind around how you go about grinding out the wood without punching through the fiberglass in the bottom of the boat.

I like to use a right angle electric grinder with the big pad and 36 grit paper. Turn it all to dust. Peel or cut the skin back first. You can use a cut off wheel on the same grinder to carefully cut and pry the skin away. After it is all ground out, wipe it down real well with acetone. Now you are ready to recore. There are many different methods of recoring a boat. It all depends on how much you want to spend.

The most common method and also the cheapest is to use balsa with polyester resin and glass. To explain this very basically... You bond the core to the bottom with corebond putty and then use a 1708 or a 2408 fiberglass overtop of it all. Polyester resin is used to saturate the glass cloth.

There are many ways to do this. This is the cheapest and easiest, but not the method I prefer. The way I like to do it, would take too long to explain in type.... Do a search. you will find alot of recore projects... Good luck.

**OFFSHORE GINGER** · 11-01-2010, 09:06 PM

Originally Posted by samari

as afr said it all needs to be redone correctly. That bulsa is completely rotten, any patch repair would be unsafe.

bulsa ?

**OFFSHORE GINGER** · 11-01-2010, 09:24 PM

Originally Posted by afr

yes you need to take it all out and recore the whole boat

come on..........recore the whole boat ... considering the rot is in the sponsom without anyone knowing how much rotted core is really there . Scott , dont you think that statment is a little pre mature and to tell you the truth ..we both know that you will never know what needs to be repaired untill you start tearing into things and to say the whole boat needs to be recored at this point...........come on ...... lets give the guy the benfit of the doubt & take it one step at a time .......sorry .

**OFFSHORE GINGER** · 11-01-2010, 09:43 PM

Originally Posted by Riverman

Chet speaks the truth. A complete recore is the only option. This is why they are called "projects"!

so what you are sayin issssssssss if one side of the boat has good core replace it all because Chet said so considering the rotted core is in the sponsom .

**Riverman** · 11-01-2010, 10:26 PM

No I'm not saying that at all. What is the chance one side is good? Not likely.

**Meatbasher** · 11-02-2010, 12:00 AM

Great feedback. I really appreciate the advise and how tos.

I will admit I'm nervous about splitting the boat in half and taking a grinder to it. It just sounds crazy. But the more I think about it the more it sounds like just dirty work more than complicated work.

There is a little more history to the boats core. It's explained the best I can on my blog...
http://ebkostinger.blogspot.com/2010/11/structure.html
As I state in the blog the rest of the core 'seems' solid as a rock. I was jumping around and punching the bottom just to see how sturdy it was and it certainly felt so.
I'm sure my neighbors thought I was crazy or something.

I'm going to get a new grinder and figure out where exactly I can work on the boat now that winter is here. I'll just start chipping away at it and see how far the rot goes.

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