67 flatback project - father and son

[RickK]

You'll  need the aft 18” or so out of the way when you rebuild your transom, so it only makes sense to do the transom first.  Then that will give you one last chance to check the hull for square and true before you immortalize it by rebuilding the stringers.

Thanks - should I take the outer skin or leave it?

I see a lot of holes in the transom but the real question is how is the glass itself?  Where they added the wood at the top, is the glass on the outside smooth or can you tell where the patch is? Remove the wood from the transom and then take a good look at the glass. Then you can decide if it is salvageable.
The best way to get the wood out of the transom is to use a skill saw and cut down almost to the fiberglass from the inside and make a bunch of cuts across the transom, maybe 2" apart.  Then take an air chisel and start peeling off the wood. If you can find a long chisel, that makes it even easier.
Then it's time to lock the shape of the hull in and make sure it is level and square.  You can remove about 8 feet of screws where the cap meets the hull sides and you can cut the cap free at the transom and prop the cap up above the hull - lay a 2x4 under the cap across the hull and figure out a way to lock the shape of the hull in. The 2x4 will help prop the cap up and hold the shape of the hull. You can screw small blocks of wood into the very top of the hullsides and attach the 2x4 going across the hull to the blocks. You will need at least 18" of clear working space forward of the transom to work in when rebuilding the transom.
Now, about those stringers... What is the width between the 2 main stringers you have left? Looks pretty far apart and your deck will sag in between them so you'll need a lot of bulkheads to support the deck. If you plan to pull all the stringers out, then you have a clean slate and can re-enforce the entire hull with an extra layer of 1708 glass or 2.  Then your stringers can be whatever you want.  I made new trapezoid stringers from scratch using 1708 and glassed them in the hull. Some people use Coosa in a framework that covers the entire hull and they design the storage they need into it. Don't use wood for the stringers (although we have people do that). Search through the Flatback rebuild forum and look for Capt.Matt's rebuild (https://classicaquasport.com/smf/index.php?topic=5724.0) - he used a lot of coosa and the boat was rock solid when he was done. Working with Coosa is like working with wood but it won't absorb water.  Look for boats rebuilt by dirtwheelsFL - he's done a few and uses different approaches.

[ncrowe]

Here's how much stuff has been removed from the project so far

[ncrowe]

So - my son and I decided to do a little more work after the clean up, and started removing the transom wood. The cap that was put on to raise the transom popped of with a pry bar in one piece. We then realized that it was not put in properly and started to look at the outer skin more closely. The outer skin was done poorly, and there was a split down the portside where the skin meets the hull side. There was also an infestation of large ants - these suckers were mean!!! IF anyone knows what they are, let us know, my son is really curious to know (see pic)











Once we realized how bad the outer skin was, and seeing how the prep work was done so poorly on the repairs, we decided to just cut out the transom leaving a 3" tab all the way around - this will be less work in the long run and a better finished product. So tomorrow we will finish getting the rest of the wood out, and start grinding back the stringers to layup the new outer skin.

[Tampa Bay Mike]

Wow, you guys have been busy! Guess you answered your transom skin question.  What's the plan for the new one?

Also, I call those suckers bull ants and yeah, they can be nasty.

[ncrowe]

Wow, you guys have been busy! Guess you answered your transom skin question.  What's the plan for the new one?

Also, I call those suckers bull ants and yeah, they can be nasty.

For the transom we’ll use 3 layers of 1708 and we’ll tab 12-8-4 using a melamine board to lay up on as I’ve seen others do

We’ll get the area all ground down to see what we are dealing with in the port side separating - a couple of clamps on the hull sides and the melamine backboard will close the gap up and allow us to secure it properly - then we’ll grind down the crack and repair from the outside with some chop strand - my thinking is if the repair is done right from the inside we should be just dealing with the cosmetics on the outside - any advice would be greatly appreciated !

[ncrowe]

Hello and happy December 1st !

So just a quick clean up - ordering some tyvec suits and a grinder and shroud (any advice would be appreciated on the shroud and grinder)

Got the rest of the transom out, and looks like there isn't a liner - I thought there was and started to peel one side - please take a look at the pic and let me know what you think.

Also, what is the best way to deal with the stringer liner? Grind it out, or try to peel it out?

Some pics for your viewing enjoyment

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Does this look like theres a liner?

[RickK]

I guess you need to decide if you're going to totally gut the boat or not. This will decide how to deal with the stringer stuff. At this point I think it is as much work ripping out all the stringers as it is to grind down the bottom portions of the stringers.  Yes, those are liners that cover the inside of the hullsides.  You may have to pop the cap loose to be able to remove that portion of liner. You want to be gentle when popping that loose. If you destroy it, you'll have a lot of filling and fairing in your future.

[ncrowe]

I guess you need to decide if you're going to totally gut the boat or not. This will decide how to deal with the stringer stuff. At this point I think it is as much work ripping out all the stringers as it is to grind down the bottom portions of the stringers.  Yes, those are liners that cover the inside of the hullsides.  You may have to pop the cap loose to be able to remove that portion of liner. You want to be gentle when popping that loose. If you destroy it, you'll have a lot of filling and fairing in your future.

Thanks Rick - by the looks of it we’ll be pulling out all the stringers at least - the center 2 are too wide apart to leave in as I understand it. And looking at how thin the hull sides are with the liner on (measuring 1/4 inch total at top to 6” down) we’re not going to risk damaging the hull sides to pull a well bonded liner -

Questions -

Grinder dust shroud - any advice?

I was thinking of leaving liner in and perimeter of old floor - is that a problem?

How many layers should I use for new outer skin?

Are foam filled stringers lighter than a comparable method?

[mshugg]

Questions -

Grinder dust shroud - any advice? I haven’t found a shroud that I was comfortable using with a flappy wheel.  The wheel is just a so aggressive that I want to see it cutting and didn’t want the additional pull of the vacuume hose.  When your a little closer to finish, this sander has a setting for aggressive stock removal, and it works great.  https://www.amazon.com/Bosch-Power-Tools-Aggressive-Woodworking/dp/B07WK42NC5/ref=asc_df_B07WK42NC5/?tag=hyprod-20&linkCode=df0&hvadid=385272107002&hvpos=1o2&hvnetw=g&hvrand=3543787148384843795&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9011811&hvtargid=aud-801381245258:pla-826243574532&psc=1&tag=&ref=&adgrpid=78829231656&hvpone=&hvptwo=&hvadid=385272107002&hvpos=1o2&hvnetw=g&hvrand=3543787148384843795&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9011811&hvtargid=aud-801381245258:pla-826243574532

I was thinking of leaving liner in and perimeter of old floor - is that a problem? Shouldn’t be a problem as long as the hull deck joint is good.

How many layers should I use for new outer skin? It’s best to build out to the same thickness as original, but most of us can’t resist adding a layer or two.   Four to six layers of 1708 should get you about 1/4”.

Are foam filled stringers lighter than a comparable method?   Not necessarily.  Remember Coosa is a denser reenforced foam.  If your stringers are in good shape, keeping them and re-tabbing should be good enough and save you time.  Wood is probably heaviest, then Coosa, then lighter foam, but as the foam density goes down, you’ll probably need to add more glass.

[ncrowe]

Questions -

Grinder dust shroud - any advice? I haven’t found a shroud that I was comfortable using with a flappy wheel.  The wheel is just a so aggressive that I want to see it cutting and didn’t want the additional pull of the vacuume hose.  When your a little closer to finish, this sander has a setting for aggressive stock removal, and it works great.  https://www.amazon.com/Bosch-Power-Tools-Aggressive-Woodworking/dp/B07WK42NC5/ref=asc_df_B07WK42NC5/?tag=hyprod-20&linkCode=df0&hvadid=385272107002&hvpos=1o2&hvnetw=g&hvrand=3543787148384843795&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9011811&hvtargid=aud-801381245258:pla-826243574532&psc=1&tag=&ref=&adgrpid=78829231656&hvpone=&hvptwo=&hvadid=385272107002&hvpos=1o2&hvnetw=g&hvrand=3543787148384843795&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9011811&hvtargid=aud-801381245258:pla-826243574532

I was thinking of leaving liner in and perimeter of old floor - is that a problem? Shouldn’t be a problem as long as the hull deck joint is good.

How many layers should I use for new outer skin? It’s best to build out to the same thickness as original, but most of us can’t resist adding a layer or two.   Four to six layers of 1708 should get you about 1/4”.

Are foam filled stringers lighter than a comparable method?   Not necessarily.  Remember Coosa is a denser reenforced foam.  If your stringers are in good shape, keeping them and re-tabbing should be good enough and save you time.  Wood is probably heaviest, then Coosa, then lighter foam, but as the foam density goes down, you’ll probably need to add more glass.

What an awesome resource this site is!!!

Thanks so much for the response - and we are moving quickly so thank you for the prompt response !

Should I be worried about the distance between the factory stringers? I’m all for saving time

[mshugg]

I’m not sure what you mean by “worried.”  It’s usually best not to reengineer any more than necessary.  Your boat lasted over 50years, so keeping stringer distances the same should make her good for another 50.

[ncrowe]

I’m not sure what you mean by “worried.”  It’s usually best not to reengineer any more than necessary.  Your boat lasted over 50years, so keeping stringer distances the same should make her good for another 50.

Thanks - The concern is in removing the center stringer - the same thing that Marcel did to his. I'm thinking the original stringers without the center wouldn't work well, so we are going to remove all the stringers and build new ones similar to the later model boats. I like the way dirtwheels did his most recent project, and I think that would work the best. Does anyone know the span between stringers on the later 22.2s with 2 stringers?

Picked up 1.5" Coosa today, 50 yds of 1708, 5 gallons of resin and a gallon of premix fillet material - I'll get the melamine sheet tomorrow and we'll have the transom skin done by the weekend and maybe even the Coosa (we'll see about that).

[ncrowe]

Alright - here's a question for those in the know:

What is all this blue stuff? I'm grinding and its basically everywhere - Also they put a truckload of bonding cement down for the stringers and its a HUGE pain to get off - i'm using 40 grit on 4.5" grinder - I think I need something bigger and more aggressive!!

DO I have to grind all of this blue stuff out (its between 2 layers of glass)

If you look at the pic - from right to left - you'll see gray (the bonding cement) - small patch of roving (inner transom skin) - blue stuff (between layers of glass) and then raw glass on the left side - I'm assuming I have to take it down to bare glass??



This picture you can see the roving and then the blue stuff under it

[RickK]

Alright - here's a question for those in the know:

What is all this blue stuff? I'm grinding and its basically everywhere - Also they put a truckload of bonding cement down for the stringers and its a HUGE pain to get off - i'm using 40 grit on 4.5" grinder - I think I need something bigger and more aggressive!!

DO I have to grind all of this blue stuff out (its between 2 layers of glass)

If you look at the pic - from right to left - you'll see gray (the bonding cement) - small patch of roving (inner transom skin) - blue stuff (between layers of glass) and then raw glass on the left side - I'm assuming I have to take it down to bare glass??



This picture you can see the roving and then the blue stuff under it

The blue stuff is bonding putty - maybe they ran out of one brand and had this on hand on Friday??   
I would go to Harbor Freight and buy a 7" grinder and pick up a couple 24grit flap sanding wheels too. If you can't find one there, HD has some pretty low # grit on flap sanding wheels. These things are vicious at tearing down anything. If you need to remove some of the "roving" (24oz), this grinding wheel will knock it down, just hang onto the grinder (and wear a tyvek plus mask and goggles). You will not regret buying the flap sanding wheels.  I also have a HF 4" angle grinder and use 4" flap sanding wheel to get into the closer qtr spaces - just fantastic at getting your work done. I got very good at using it for many things (even my wife complaining about the bottom of her pan being funky - DONE with the flap sanding wheel in a couple seconds - the pan bottom, not my wife  ). Did I mention that the flap sanding wheels are fantastic?

[RickK]

Oh, and you just need to grind down to clean glass - don't overthink it - post pics and we can advise. You can glass over 24 grit results in some applications but you might need to be more gentle in some areas with a 80 grit wheel. The wheels last a long time. They don't like uncured resin though (don't ask how I know this) and they are ruined after that.