How to fix gap in side of fiberglass hull

[BlueBell]

Aaron,

I'm curious, why didn't the previous owner repair the hull?
Did he/she lose the outboard on impact?
What did you pay for the boat and are you planning to keep it or sell it after the repair?
Do you still feel this is cost effective learning?
And finally, is there no one in your area that can give you an assessment / guidance, in person?

Sorry, that's a lot of questions and some of them I've asked before but you didn't answer.
I'm just trying to get a sense of where you're coming from and where this is going.

Cheers!

 

[aaronhl]

Stay tuned for more pics and if anyone wants to chime in go for it

 

[ondarvr]

With more pics it looks like the boat basically hinged right in that area, and almost all the way across. Thin laminates like that can help and hurt. Thin laminates can flex more on their own without much damage, but as a skin over a core they fail, sometimes over large areas. They also peel off the core easily if water gets in at speed

Can you inspect the laminate all the way across in that area to make sure it's in good shape?

 

[fallguy]

Okay, I can tell you that the stringers or hull are compromised with a high degree of certainty.

This boat lacks a structural bulkhead that it needs. Typically this is done with a seat bench. The cap broke first because the boat is flexing due to compromised stringers or general abuse. Then the real test happened when they slammed into some big seas and the hull completely flexed which caused the aft cracks. I can almost promise bad stringers; delamination of stringer to hull and delam of hull across the bottom.

The only thing to do is open the floor between the cap and broken sides.

For all intents and purposes, this boat is toast. I hope you didn’t pay too much.

 

[fallguy]

You’ll need to verify the hull bottom. Nothing else matters.

1. Verify balsa core is not present in bottom. If it is, it is likely soaked and cannot be used unless recored or changed to solid glass. Not worth it. The problem is diseconomy. You’d spent 400 hours and $1000 on it and in the end the boat is worth 3-4k? So, your time bills out at $5-$7.50 an hour or worse if over the 400 hours which is easy here on recoring.

2. Verify stringers and hull bottom have not delaminated significantly. This can be done easily. If you tap the bottom and the hull fails the tap test; you can haul to the dump. Or, if it doesn’t fail; you must open the floor and inspect. A core boat with a major failure might even flex with finger pressure. End of life.

I’ve seen a few boats with cracked caps and the story is almost universally the same; they have suffered a structural failure before the cap cracks. Most commonly a core failure or rotten stringers.

Hope I’m not piling on, just trying to be edifying. I noticed my red circle missed the port side cap break. Touche’. Good luck.

 

[wet feet]

How about an interior pic showing how far inboard you bottom repair will be going?I don't necessarily share the feeling of doom,but you may be in for more work than you initially bargained for.What size motor was on the boat when the damage occurred and what is the maker's recommended maximum power?

 

[ondarvr]

I think what people are concerned about is how much the hull must have flexed from the extreme stress required to do this type of damage, and the small area being examined and repaired

 

[fallguy]

In order for damage to occur simultaneously to these four locations, the boat would have needed to flex somewhere along the green axis. In order for that type of stress to occur, the bottom had to bend; a lot.

 

[wet feet]

I've already asked for an interior shot of the bottom and now I'd like to add a request for a shot of the port side from about the same angle and distance as the view fallguy has annotated.I am extremely curious about the power of the motor that was on the boat at the time of the incident,but that won't have any effect on the repair strategy.

 

[aaronhl]

I can see why you guys are concerned about the damage and how a severe "bending" of the hull could have caused the damage. I will be checking the stringers and underside more this weekend and report back...here are some additional pics and to answer the question about the horsepower it was a 300hp Merc outboard with about a foot setback jackplate...

I feel it may have been a force (that kept the bottom in place) but instead pushed up on the top deck. And the reason when the hole is in the side or bottom is because the top deck took a soggy side support with it. I noticed the starboard side floor vertical "cubby" is mostly wet along the bottom...you can see a crack where it meets the floor...I will be checking several feet forward of this for issue to the core underneath it

 

[fallguy]

Just light or is this discolored? If discolored, this is the flexion point. And you can tap test it and see if it has a different sound thru here.

 

[aaronhl]

It has been raining non stop for last two days I believe the discoloration is sunlight, maybe even the mat I was laying on. When it dries up I will try to get some better pics.

I did however, bang along the back approx 1/4 of the boat on each side and it seemed very solid.

When I saw the pics before seeing the boat in person, I was like you guys expecting a "crease" along the bottom like breaking of at station 2 but when I finally saw it in person the bottom looked a felt great, somewhat of a pleasant surprise to not see outside damage. There are some floor covers I will be opening to look into the stringers too

 

[aaronhl]

I've been busy working on this and will have some updates with pictures - The weather has been tough to work around especially with it barely reaching 60 for a few days in a row, good thing I have a heat gun and a tarp over the boat,

So when I start repairing from the outside, I plan to grind away cracks and put down chopped matt before gelcoat, but I can only imaging having to FAIR somewhat before the gelcoat. would it be ok to use a little bit of bondo to fair some areas of the matt before i put gelcoat on ? does that make any sense what im trying to say?

 

[fallguy]

Bondo is hygroscopic and takes on water. It belongs far away from boats and houses. The reason it works on cars is it is trapped between steel and clearcoats. Once wet, it expands, too.

 

[wet feet]

You are likely to need some kind of fairing compound and while I understand what Bondo is,I've never seen it or used it.If you mix your own compound using resin and microballoons,it won't be hygroscopic and can be shaped.Using the same resin you are repairing the hull with will be fine although for the first try you may have to experiment a little with catalyst ratios.Maybe by this stage of the process you will have realised why I prefer building a good temporary mould section on the outside and leaving as little finishing as can be achieved.It takes a lot less time to finish a 3/16" wide gel line than to create an entire surface that is fair.It does however require boatbuilding ability in a reverse shape.