Cheap floor and foam replacement for weekend.

[pikeman2240]

Hi all. New here.

I got an older boat, 18 foot 1980 champion inboard fiberglass boat with a 120hp engine. Pretty sure the floor is rotting and the foam is waterlogged. Engine and sterndrive are in great condition. No leaks at all. This is my first fiberglass boat.

So I can drive the boat as it is but just takes very long to get on plane and can't carry much for passengers.

What I'm hoping to do is rip out the flooring and the foam. But, I can't really afford to replace the foam and the floors properly this year. Mind you, I live in Canada in marshlands, around small lakes and rivers. I need a boat to do some moose hunting and fishing very soon. Proper repairs are planned for next year in the spring but just can't afford it right now.

So I'm wanting to gut it and just use the cheap white Styrofoam and slap some half inch or 3/4" plywood down for the floor. Would this suffice for a weekend of boating? Or is there a reason aside from using wood and resin and all that other stuff aside from waterproofing.

I'm just trying to save weight so I can load up passengers and our camping gear. The lakes might get a little choppy with no more than 1-2 foot waves and the rivers are shallow with really low current so it's basically like glass.

I do plan on ripping everything out anyways and storing the boat for winter, saving up and doing my research over the winter before repairing the floors and foam next spring. I'm just trying to get one good weekend out of my boat but if what I'm trying to do is dangerous then I'll just stick with a waterlogged boat and travel slow with less gear.

Thanks in advance for any input and advice.

 

[tpenfield]

Not the best of plans, and probably will not work out for you.

If you want to get rid of some of the water weight and plan for the proper rebuild next year, you could try to suck the water out of the foam filled compartments as an initial step. (if they are in fact holding water)

Since we cannot see your boat, we cannot really provide any judgement as to how sound the hull currently is, or its ability to remain floating in an 'unplanned' event.

Proceed with caution.

 

[charliedaubitz1]

There are different density's of foam, there are also foams that you mix part A and b. Use a hole saw and cut holes in some of the soft parts, remove as much old foam as you can, replace it with high density foam. put a good board over the hole and the remaining soft spots. Just for a temp fix. Great stuff spray foam is too light. Make sure you have a working bilge pump.

 

[JASinIL2006]

And wear your life vests.

 

[airshot]

What you really need to check is the superstructure of the hull. Fiberglass boats use wood for a skeleton to support the fiberglass which has very little strength without the skeleton. If the wood is rotted and lost its support, a good chop and extra weight could fold up your hull like a piece of wrapping paper ! Are you willing to take that gamble ?

 

[charliedaubitz1]

What you really need to check is the superstructure of the hull. Fiberglass boats use wood for a skeleton to support the fiberglass which has very little strength without the skeleton. If the wood is rotted and lost its support, a good chop and extra weight could fold up your hull like a piece of wrapping paper ! Are you willing to take that gamble ?

drill a hole in the floor the same size as shop vac nozzle, stick the nozzle in there and leave it running with the hole sealed. You'll be surprised how much water it picks up if that foam is saturated.

 

[jbcurt00]

Decking over soft spots in the deck is never a wise idea.

If the boat won't plane there's a lot of water held below deck, no shop vac will pull meaningful amounts of water.

And deck over doesn't deal w waterlogged/rotten stringers which are exceptional likely

 

[pikeman2240]

We did take it out in some choppy water, probably the biggest waves the boat will ever see in the rest of its life and it held up great. The transom is solid and doesn't show any signs of rot so I'm hoping the stringers are fine too, if they do need to be replaced then it will be done next year too.

The website won't let me attach a picture.

In the event of something happening. We will have other boats with us and we're usually within 200 meters from the shore at any given time. 90% of the time we're sitting in small bays fishing.

This is my first fibreglass boat. I've only ever had 16 foot aluminum boats with 20-50hp outboards. From my understanding, the hull is all fiberglass and just a shell. Stringers are kind of like the rafters and joists that make up a roof. It gives the hull structure and strength. Keeps it from folding, bending, flexing etc..

As for the foam, it's there help keep the boat afloat in the event of water getting into the hull, less water volume in the hull equals less weight. And there is a bilge pump that works really great. We know thanks to someone forgetting to put the plug in at the boat launch. To me, the jist is less water in the hull = less weight. Foam = less volume area for water to fill. I just have access to the cheap white stuff for free and would only be a temporary solution.

Now the floor, I don't understand what it does for the structure of the boat. I've heard of people using aluminum or wood, so I figured I'll just slap some tough plywood down and glue the old carpet ontop to give us something to walk on, again I have access to plywood I can use that can be disposed of after a weekend and it's not intended for long term use.

Right now, money is the problem. I just can't afford nor do I have the time to go get good plywood, resin, fibreglass, foam etc.. and do a job that will last the boat for years. That's planned for next spring.

To me. The hull, stringers and transom are what's important. I just don't really see how the floor and foam keep my boat from folding/snapping in half. Foam = float if water gets in. Floor = something to walk on.

I might be being ignorant to other factors but I'm new to fibreglass boats but at the same time I'm not trying to throw in that cheap plywood made of dust and call it a day.

I'm going to take the floor and old foam out regardless. Check the stringers and inside of the hull. If everything is good then it's temporary floor and temporary foam. If everything isn't OK then the boat will be prepped for winter storage and a list of what needs to be fixed will be made.

This is all new to me and I'm learning as I go. If what I'm trying to do will work, let me know and if there are any precautions i should take or things i should watch out for. Please let me know.

But if it won't work, can you explain to me why it won't, I'm here to learn. Thank you for any and all advice.

 

[pikeman2240]

https://imgur.com/a/m9AYwAa

 

[todhunter]

The floor ties together the tops of the stringers and does play a role in structural support. The foam also plays a key role in rigidity of the hull. Without foam, you may be surprised how much the hull and floor will flex.

 

[THEHIGHAMS]

We did take it out in some choppy water, probably the biggest waves the boat will ever see in the rest of its life and it held up great. The transom is solid and doesn't show any signs of rot so I'm hoping the stringers are fine too, if they do need to be replaced then it will be done next year too.

The website won't let me attach a picture.

In the event of something happening. We will have other boats with us and we're usually within 200 meters from the shore at any given time. 90% of the time we're sitting in small bays fishing.

This is my first fibreglass boat. I've only ever had 16 foot aluminum boats with 20-50hp outboards. From my understanding, the hull is all fiberglass and just a shell. Stringers are kind of like the rafters and joists that make up a roof. It gives the hull structure and strength. Keeps it from folding, bending, flexing etc..

As for the foam, it's there help keep the boat afloat in the event of water getting into the hull, less water volume in the hull equals less weight. And there is a bilge pump that works really great. We know thanks to someone forgetting to put the plug in at the boat launch. To me, the jist is less water in the hull = less weight. Foam = less volume area for water to fill. I just have access to the cheap white stuff for free and would only be a temporary solution.

Now the floor, I don't understand what it does for the structure of the boat. I've heard of people using aluminum or wood, so I figured I'll just slap some tough plywood down and glue the old carpet ontop to give us something to walk on, again I have access to plywood I can use that can be disposed of after a weekend and it's not intended for long term use.

Right now, money is the problem. I just can't afford nor do I have the time to go get good plywood, resin, fibreglass, foam etc.. and do a job that will last the boat for years. That's planned for next spring.

To me. The hull, stringers and transom are what's important. I just don't really see how the floor and foam keep my boat from folding/snapping in half. Foam = float if water gets in. Floor = something to walk on.

I might be being ignorant to other factors but I'm new to fibreglass boats but at the same time I'm not trying to throw in that cheap plywood made of dust and call it a day.

I'm going to take the floor and old foam out regardless. Check the stringers and inside of the hull. If everything is good then it's temporary floor and temporary foam. If everything isn't OK then the boat will be prepped for winter storage and a list of what needs to be fixed will be made.

This is all new to me and I'm learning as I go. If what I'm trying to do will work, let me know and if there are any precautions i should take or things i should watch out for. Please let me know.

But if it won't work, can you explain to me why it won't, I'm here to learn. Thank you for any and all advice.

The stringers are like roof ties or body struts for a car. The sort of keep the hull firm and not well bendy (firm) the stringers go from one side of the hull to the other and cut to the shape of the hull probably 8 to 9 inches high. The they are stuck to the bottom of the boat by encapsulating (covering them totally) with fibreglass also sticking a overlap to your fibreglass hull. You can lay your marine ply over the top. Sealing all sides to the hull with fibreglass putty. But when you have done that you will have pockets where each stringer goes across. The best way to fill those voids is to fill them with expanding foam. Drilling a hole in each void (make sure you mark each stringer on the floor ply is before fitting) so if you've go 8 pockets drill 8 holes 2" diameter keep the cutting out bits of wood. Drill a 10 mm hole opposite. Fill with foam when it starts to expand and come up through the big hole keep a piece of wood or cloth over it till you see quite a bit expanding foam Coming out of the other hole this way you know the soil is completely full. And like someone said the foam acts as buoyancy , more structure to the hull as this stuff sticks like gorilla glue and because the foam is there not a lot of water gets in because the foam is there. This is exactly what I'm doing now I didn't understand at 1st . All my 9 stringers were like mush.the foam was saturated. The wet foam must have weight 80/90 kilos if not more. The foam does work but must have a life span of maybe 15 years.
Hope this explanation helps.
Thanks
Kenneth
Ps I tried to upload some pics but site won't let me

 

[mattsteg]

There's not really a meaningful half-measure once you start digging in to things and ripping out foam.

 

[THEHIGHAMS]

There's not really a meaningful half-measure once you start digging in to things and ripping out foam.

No that's 100% True, once you start. There's No going back get stuck into it and get as much help and advice you need look at the repair and look again,again and again before you start simply because no turning back just finish That particular job. Lol don't switch to something else .
Good Luck
Kenneth

 

[mattsteg]

No that's 100% True, once you start. There's No going back get stuck into it and get as much help and advice you need look at the repair and look again,again and again before you start simply because no turning back just finish That particular job. Lol don't switch to something else .
Good Luck
Kenneth

That's not to say you can't use a partially completed project...but if you can't afford to replace floor and foam you don't rip it out - especially since the "cost" to do it right is far more time than money.

 

[pikeman2240]

Aside from waterproofing the floor. Is it absolutely critical to use resin and fiberglass on the floor? Or will some strong plywood be good enough to use for a few days. Again, this plywood is good, it ain't cheap but it isn't the best either, it's temporary.

And aside from preventing water from taking up less volume in the hull, is there a reason why I can't use the cheap white foam for a few days too?

If needed, the guy included 2 extra bilge pumps. The boat has A/C and a stereo with crap speakers. I'm sure I can remove those and wire in the extra pumps incase of emergencies.

I'm just failing to see how it's any different than using cheap vinyl for your floors in a house while waiting for hardwood and using cheap insulation until you can get the good stuff. I'm just under the impression that the structural support is all in the hull and stringers. The rest are just kind of accessories and personal preference.

 

[Scott Danforth]

Yes, the floor needs to be glassed in for strength

 

[THEHIGHAMS]

That's not to say you can't use a partially completed project...but if you can't afford to replace floor and foam you don't rip it out - especially since the "cost" to do it right is far more time than money.

Possibly more money than the boats worth, But it's YOUR BOAT. that's where it hits your pocket & your bank balance.

 

[mattsteg]

Possibly more money than the boats worth, But it's YOUR BOAT. that's where it hits your pocket & your bank balance.

The bane of old fiberglass boats and the type of rehab they can require.

Aluminum, if the hull is sound you can more or less always make the boat operational at a reasonable price. You might choose to go beyond that on a boat you're gonna keep (and a lot of us do) because you're still saving vs what you would buy otherwise, want something specific, or just enjoy the work.

If the cost of some fiberglass and resin is a stretch...man that's a red flag to me that this could turn very sideways.

 

[Chris1956]

It is probably better if you do not rip the boat apart and patch it for the season. If you rip out the foam and rotten wood, and do not replace it with new foam and properly attached wood, the boat could be weaker than it is now.

Alternatively, you could screw down some new plywood decking over the old, until you get to it's real repair. The waterlogged foam I do not have an answer for. It must be ripped out and replaced to maintain the strength of the hull.

I had an 18' SeaRay, and the hull was likely not completely foamed. The hull cracked between the stringers on a day that was about typical in roughness. I had to pull the boat before it sunk.

BTW stringers run bow to stern and give the hull it's strength. The foam is installed between them to support the hull, in conjunction to the stringers. You likely have 2 flanking the keel section, two more near the vertical to vee transition of the hull, and 2 more 1/2 between. Frames run side-to-side. You likely have one in front and behind the fuel tank.

If it were me, I would make some volume calculations for the new 2 part pour-in foam needed (vol of a rectangular wedge, should be close), and price it out.

Then price out 1/2 plywood for the deck. plus 2 layers of a middle weight cloth and a couple gallons of resin. Amazon has some good prices on cloth and resin. If the stringers and transom are solid, the repair will not take very long.

Cut out the old deck with a sawzall, chisels etc., dig out the old foam with hands, prybars, putty knives etc. Dry everything out and pour in the new 2 part foam. Cut it flush with the top of the stringers. Cut the plywood to size and screw to stringers with stainless steel screws. Now mix up a qt of resin and lay the glass. A qt at a time is a good volume, as it can be brushed on within the working time of the resin. A couple of more coats of resin over 2 layers of medium weight cloth and you should be structurally sound.

The good news about resin, is that once you mix it with hardener, it use needs to be pronto. This forces you to finish the repair.

Just my opinion.

 

[mattsteg]

It is probably better if you do not rip the boat apart and patch it for the season. If you rip out the foam and rotten wood, and do not replace it with new foam and properly attached wood, the boat could be weaker than it is now.

Alternatively, you could screw down some new plywood decking over the old, until you get to it's real repair. The waterlogged foam I do not have an answer for. It must be ripped out and replaced to maintain the strength of the hull.

I had an 18' SeaRay, and the hull was likely not completely foamed. The hull cracked between the stringers on a day that was about typical in roughness. I had to pull the boat before it sunk.

BTW stringers run bow to stern and give the hull it's strength. The foam is installed between them to support the hull, in conjunction to the stringers. You likely have 2 flanking the keel section, two more near the vertical to vee transition of the hull, and 2 more 1/2 between. Frames run side-to-side. You likely have one in front and behind the fuel tank.

If it were me, I would make some volume calculations for the new 2 part pour-in foam needed (vol of a rectangular wedge, should be close), and price it out.

Then price out 1/2 plywood for the deck. plus 2 layers of a middle weight cloth and a couple gallons of resin. Amazon has some good prices on cloth and resin. If the stringers and transom are solid, the repair will not take very long.

Cut out the old deck with a sawzall, chisels etc., dig out the old foam with hands, prybars, putty knives etc. Dry everything out and pour in the new 2 part foam. Cut it flush with the top of the stringers. Cut the plywood to size and screw to stringers with stainless steel screws. Now mix up a qt of resin and lay the glass. A qt at a time is a good volume, as it can be brushed on within the working time of the resin. A couple of more coats of resin over 2 layers of medium weight cloth and you should be structurally sound.

The good news about resin, is that once you mix it with hardener, it use needs to be pronto. This forces you to finish the repair.

Just my opinion.

Yup the cost of doing it right is not that much different from the cost of doing it wrong, and it doesn't set you up to break things.

Of course you might run into more that needs doing.