Why do you have to start FG repairs from the inside

Ok so I havent posted any on this forum before have just read through other postings and am really impressed on what people have done. For myself I have a jetski that i bought with a basball sized hole in the front and then half the bottom left side had the gelcoat and one layer of fiberglass shaved off from hitting something. Anyways first of all I understand that pics are needed which I will be posting. My question while reading through all these diff post's is why is it that you need to start the work from the inside on most of these jobs other then to assess the damage on the inside. Reason I ask is pretty much if I have a baseball sized hole and lets say the inside is with no damage cutting out the hole then laying fiberglass over it with a 1 inch over lap followed by bigger pieces until complete, why wouldnt that work better then starting on the inside, since the force of the water will be pushing from the outside in. In my thinking I see where it would be harder to push a plug into a smaller hole and out the other side then pushing the plug out. I dont know if im making sense to anyone one else, but if I am and you have time can you help me in my thinking, or is it pretty much to just evaluate the interior damage and to put layers on both sides for added strength. Just a thought before I get started.

Re: Why do you have to start FG repairs from the inside

The biggest reason is as you said, it gives you a chance to see any other damage from the inside. I've never repaired a jet ski, so I'm not familair with the hull make up...stringers, bulks etc. If you're confident the damage is only where the hole is, then it can be repaired from the outside.

A patch made from both sides provides a better bonding area as well as strength, but again it can be done from the outside only...

CW

Re: Why do you have to start FG repairs from the inside

Welcome to Iboats Joaquin .. .

You are spot on with your theory. Glassin from the outside first is how I do these small repairs. Your right about pushing a cork into a bottle rather that out of a bottle kinda thing.

Only if the repair is so big that I could use something to shape the repair on the outside is when I start glassing from the inside first. I dont need to glass the whole outside.. just around the grind seam.

YD.