Gulf Coast 18 Fiberglass Repair and Other Refitt Tasks

[M.B. Naegle]

I'm just starting into this project and would be happy to have any input or advise. I picked up this Gulf Coast 18 as a first project. Not sure of it's full history other than it was part of a university sailing program or club that was abandoned on a property with 30-40 other sail boats. Other than needing new rope and sails and some other misc. pieces, the biggest task will be fixing fiberglass damage and repainting the whole thing.

The biggest hole is in the back where the motor mount was ripped off of the transom. Not sure if it happened in or out of the water, but the exposed plywood is rotten. The motor mount is still with the boat luckily. There are also a couple cracks in the side of the house and the aft starboard deck, and several smalk bullet holes in the bow, but all those I think will be simple glass jobs.

Full disclosure, this is my first time working with fiberglass, but I've done a lot of classic car body work and have a machine shop to sort this stuff out at after hours.

The biggest challenge is that I can't get to the inside of the damage for nearly all of these repairs, so I see this going one of three ways.

1: Keep it simple and do all the glass work from the outside only. Might not last as long, or might work out fine, but it'll get the boat back in the water the fastest.

2: Split the hull top and bottom along the seam to fix it "right".

3: Cut away the top aft decking to give access to the worst damage and replace the fiberglass deck afterwords with stained sealed plywood planks, screwed in place.

In all three cases, I plan to start at the transom sawing and grinding until I have clean edges and no rot or delamination (possibly the whole panel) with a 4" wide taper, cut a piece of plywood to fit the hole, fiberglass the back and edges first then start sealing it into the hole. While finishing the exterior glass, I'll either fiberglass the inside seams or add some additional filler, depending on how much access I have.

The deck cracks I can get to both sides, and the bullet holes are small enough to fix with putty or small fiberglass disc's.

[M.B. Naegle]

Here's some more pics of the boat. The wood will all get replaced using the old pieces for patterns. I have some 1" red oak planks that will work for some stuff if sealed right, and I'll get a sheet of 1/2" marine plywood for the rest.

Still mulling over paint and color schemes, but I like the blue and white. In addition, I want to add some red to it, like a red stripe, red seats, and possibly red sails.

This'll be a lake and gulf coast day cruizer, but I want it to have the potential for overnight campouts, so getting the deck lights rewired will be a latter task and I'd like to add a solar panel to the housetop. There's a hole in the bulkhead that I think once held a compass, which I would want to put back.

[wyb2]

Originally Posted by M.B. Naegle

…
Still mulling over paint and color schemes, but I like the blue and white. In addition, I want to add some red to it, like a red stripe, red seats, and possibly red sails.

This'll be a lake and gulf coast day cruizer, but I want it to have the potential for overnight campouts, so getting the deck lights rewired will be a latter task and I'd like to add a solar panel to the housetop. There's a hole in the bulkhead that I think once held a compass, which I would want to put back.

You are quite a ways from having to worry about any that stuff. Those are not trivial repairs. The only thing you should be thinking about is fiberglass repair.

I don’t see any way to fix that boat without pulling the deck off the hull. Look at that caved in sidedeck/coaming, you cant repair that in place, there’s no good material left to bite onto on the outboard edge. You need to separate the joint and rebuild the “L” that interfaces with the deck from scratch.

I suppose you could plan to pull the rub rail and glass the whole joint together, but seems like that would make other things harder, like the transom.

Speaking of the transom, there’s very little chance you are getting away without cutting away either the entire inside or outside skin and replacing the wood core. I suppose if by some miracle much of it is dry, you wouldn’t have to, but you are already doing major work on it, for 50% more work you will get 1000% better results.

There are hundreds of people on here that know 100x what I do about fiberglass repair, but you said you are a total novice, so this is what a slightly-less-of-a-novice sees. I’m sure others will chime in with better info.

[M.B. Naegle]

Originally Posted by wyb2

You are quite a ways from having to worry about any that stuff. Those are not trivial repairs. The only thing you should be thinking about is fiberglass repair.

I don’t see any way to fix that boat without pulling the deck off the hull. Look at that caved in sidedeck/coaming, you cant repair that in place, there’s no good material left to bite onto on the outboard edge. You need to separate the joint and rebuild the “L” that interfaces with the deck from scratch.

I suppose you could plan to pull the rub rail and glass the whole joint together, but seems like that would make other things harder, like the transom.

Speaking of the transom, there’s very little chance you are getting away without cutting away either the entire inside or outside skin and replacing the wood core. I suppose if by some miracle much of it is dry, you wouldn’t have to, but you are already doing major work on it, for 50% more work you will get 1000% better results.

There are hundreds of people on here that know 100x what I do about fiberglass repair, but you said you are a total novice, so this is what a slightly-less-of-a-novice sees. I’m sure others will chime in with better info.

Thank you. What you say about replacing the whole transom makes a lot of sense. I was planning on making a template of it showing prior hole locations, but if I split the boat AND cut out the transom, a template would also help to ensure that the back of the boat doesn't get wider or narrower.

I agree that the glass work will be the primary task to start with. But I would like to have a plan in place for the later tasks as well, as if there are holes that won't be needed anymore, I'd rather fill them now then later. The plan also gives some motivation when I'm sick of fiberglass, lol.

Having the deck off would also help to better inspect/repair things that can't be seen. Looking inside I can't see any wood bracing, but there are some foam blocks under the seat that look a little loose. I read somewhere that they used Iron for ballast on these boats, which I imagine is encased in the hull glass, but it would be good to check out.

I watched a couple videos about splitting fiberglass hulls, and one thing I'm not sure about is how are they adhered together? Glue, glass resin, screws, or does it just depend on the manufacturore? Mine has an aluminum rail around the perimeter held on with pop rivets. After drilling out the rivets to remove the rail, the procedure as I understand it would be to find the seam and gradually wedge it apart around the boat, correct?

[M.B. Naegle]

A couple other notes: one of the above pictures shows a prior repair that never got painted, so that would also be good to further inspect.

Also in the cabin it looks like someone added more storage compartments, which I like, but they are a little rough, so while the hull is apart would be a good time to clean up the edges.

They also added four inspection ports around the boat, which don't look original (don't appear on other Gulf 18's I've seen pictured), but are good to have. I might change where they are however.

[wyb2]

Originally Posted by M.B. Naegle

Thank you. What you say about replacing the whole transom makes a lot of sense. I was planning on making a template of it showing prior hole locations, but if I split the boat AND cut out the transom, a template would also help to ensure that the back of the boat doesn't get wider or narrower.

I agree that the glass work will be the primary task to start with. But I would like to have a plan in place for the later tasks as well, as if there are holes that won't be needed anymore, I'd rather fill them now then later. The plan also gives some motivation when I'm sick of fiberglass, lol.

Having the deck off would also help to better inspect/repair things that can't be seen. Looking inside I can't see any wood bracing, but there are some foam blocks under the seat that look a little loose. I read somewhere that they used Iron for ballast on these boats, which I imagine is encased in the hull glass, but it would be good to check out.

I watched a couple videos about splitting fiberglass hulls, and one thing I'm not sure about is how are they adhered together? Glue, glass resin, screws, or does it just depend on the manufacturore? Mine has an aluminum rail around the perimeter held on with pop rivets. After drilling out the rivets to remove the rail, the procedure as I understand it would be to find the seam and gradually wedge it apart around the boat, correct?

For the keel, looks like this boat has (had?) an iron swing keel.

https://sailboatdata.com/sailboat/gulf-coast-18

Most likely a solid casting. If yours is missing, check eBay maybe? At 325 lbs, making something yourself probably isn’t totally out of the question.

For the deck/hull joint, I think it does depend on manufacturer. I think most common is the hardware (rivets, screws, bolts) is structural, and some sealant is used to make the joint watertight. If they used a good quality sealant though, it may be a bit of a chore to pry it apart even after the rivets are all drilled.

I should reiterate though, if you do get this back on the water, you will know more about boat repair than I do. Hopefully some others chime in.

[wyb2]

Leaving this here for reference on the deck/hull joint.

http://www.jordanyachts.com/wp-conte...eck-joints.jpg

[M.B. Naegle]

Originally Posted by wyb2

For the keel, looks like this boat has (had?) an iron swing keel.

https://sailboatdata.com/sailboat/gulf-coast-18

Most likely a solid casting. If yours is missing, check eBay maybe? At 325 lbs, making something yourself probably isn’t totally out of the question.

For the deck/hull joint, I think it does depend on manufacturer. I think most common is the hardware (rivets, screws, bolts) is structural, and some sealant is used to make the joint watertight. If they used a good quality sealant though, it may be a bit of a chore to pry it apart even after the rivets are all drilled.

I should reiterate though, if you do get this back on the water, you will know more about boat repair than I do. Hopefully some others chime in.

Yes the swing keel is there. I was thinking there was some additional weight, but if not that's one less thing to worry about. Being able to remove it will help in moving the bottom half around.

[Spot]

Welcome to the forum Miles. That is going to be quite a project!

If you do separate top from bottom, what provisions will you need to make to insure that the hull goes back together with a reasonable degree of staight-ness and fair-ness?

My kid brought home a holed hull last fall, I will be in that same pew soon enough...

My rebuild, not as extensive but nevertheless seasons long-lasting, is here:
https://www.cruisersforum.com/forums...ml#post3182241

[M.B. Naegle]

So I did a little more crawling around in/on the boat today and made a few discoveries. For one, I found the old compass down in the bilge. It's an old Aqua Meter that'll need a new rubber diaphragm and fluid. Also found a cast iron anchor down there.

The Cabin area is bigger than I thought, but it also complicates the idea of splitting the hull. There are three main sections, the top, bottom, and cabin floor. The outer seam is easy to follow, but where they all converge in the middle is a little more complicated. I was also under the impression that the bilge was a separate sealed space, but under the door it merges with the cabin interior. When the prior owner added additional storage lockers in the cabin floor, they made them out of painted plywood and it looks like they glassed them to the hull. I'll need to replace the plywood, but separating the hull from the cabin floor won't be easy.

[M.B. Naegle]

Here's some more pictures.

[Spot]

Oscillating multi-tool with good carbide blades will make short work of freeing plywood tabbed to a hull. I removed about 32 lineal feet in my boat. Cheap steel blades only last a foot, a good blade will last 10-20 feet or more. You will need to consider how you will rebuild/replace any load-bearing elements that are removed.


PS Love the old lights and compass. My Airguide was too far gone to repair.

[wyb2]

Originally Posted by M.B. Naegle

So I did a little more crawling around in/on the boat today and made a few discoveries. For one, I found the old compass down in the bilge. It's an old Aqua Meter that'll need a new rubber diaphragm and fluid. Also found a cast iron anchor down there.

The Cabin area is bigger than I thought, but it also complicates the idea of splitting the hull. There are three main sections, the top, bottom, and cabin floor. The outer seam is easy to follow, but where they all converge in the middle is a little more complicated. I was also under the impression that the bilge was a separate sealed space, but under the door it merges with the cabin interior. When the prior owner added additional storage lockers in the cabin floor, they made them out of painted plywood and it looks like they glassed them to the hull. I'll need to replace the plywood, but separating the hull from the cabin floor won't be easy.

I’m having a little trouble following your description. But I’m guessing the boat has a typical construction where the hull, the interior liner or pan, and deck come out of 3 different molds. (I think this is the top/bottom/floor you are talking about.). Then the liner/pan is bonded/tabbed/glassed to the inside of the hull, then the deck is fastened on top.

Unless there is something I’m not seeing, you should be able to get the deck off without messing with the hull to liner attachments.

[M.B. Naegle]

Originally Posted by wyb2

I’m having a little trouble following your description. But I’m guessing the boat has a typical construction where the hull, the interior liner or pan, and deck come out of 3 different molds. (I think this is the top/bottom/floor you are talking about.). Then the liner/pan is bonded/tabbed/glassed to the inside of the hull, then the deck is fastened on top.

Unless there is something I’m not seeing, you should be able to get the deck off without messing with the hull to liner attachments.

I'm probably over thinking it. Initially I was figuring how to get the hull bare, but I guess the inner pan (sorry, still learning all the terms) can stay on the hull. To get just the top shell off, I'll need to find the seam between it and the inner pan under the door, and then figure out how to separate it from the keel well. The only advantage to getting the inner pan out of the hull would enable a better repair of the bullet holes in the bow, but I think they're small enough to do from the outside, and everything forward of the storage lockers under the inner pan is full of foam too which I think would make it hard to pull apart.

With the exception of the bullet holes and storage lockers, the front half of the boat is in really good shape, glass-wise, so I'm wondering if instead of taking the whole top off, I could cut it down the middle and only remove the back, OR, depending how flexible it is, If I can separate the back seam and just lift it 6-12", that would give me enough room to fix the transom and put a temporary backing panel under the hole in the top for its new glass.

There is a 6" inspection hole near the transom damage that I think was added to allow access to bolt the motor mount on, so before I start splitting the boat, I want to see how difficult it'll be to use it to seal the inside of the new transom panel. This is assuming I can grind away the outer skin and wood and leave the inner fiberglass skin intact.

[wyb2]

Ok, I think I see the problem, is the underside of the cockpit floor bonded to the top of the keel trunk (arrow in picture)? That would be a bit of a hurdle. If it’s tabbed you can go at it with an oscillating tool like Spot suggested. If they gooped up the whole topside of the trunk before dropping the deck on top, that’s a trickier problem, not sure I have a good suggestion to get around that.