Stringer placement and fiberglass questions

[Baylinerchuck]

Wow, that's an intricate stringer layout. Very nice coping there!

 

[61mysteryboat]

this is a photo of the stringer assembly I made to replace the original. I made it exactly like the original. the joints are half lapped at the intersections. the original half laps were screwed at the intersections from the bottom. this showed me that the stringers had been assembled prior to installation. only difference is that I glued the intersections with pl. the premade assembly will assure that the floor is flat. I am aware that this will be very hard to glass. I am open for advice. if I need to change it I will. I succeed through perseverance

 

[gsxrdan]

Great effort so far! Gotta ask, hows the transom?

 

[61mysteryboat]

It was rotted. I spent three days digging it out. I have the replacement plywood cut and fit. Just waiting to glass it in.

 

[gm280]

61, that stringer layout looks great. If I am understand you, you already glued it together? So that does present a new cog in the wheel. If the ribs, braces or bulkheads (whatever you want to call them) were fastened from the top instead of the bottom to the actual stringers, you could have installed the stringers in place first with the PB and then at your time and pace installed all the ribs, braces, bulkheads. Is there anyway to disassembly them. :noidea:

 

[61mysteryboat]

Yep,. All glued together. My main concern is getting the fiberglass properly fit into all of those inside corners. It would be possible to bed all of the ribs in pb. Cut the stringers out after the pb has set ( this would ensure that the ribs are level). Would it be feasible to not install the stringers and fill the area with high density pour in foam to add rigidity to the hull after the ribs are glassed? It is an 18' boat with 2" tall ribs and stringers.

 

[gm280]

Yep,. All glued together. My main concern is getting the fiberglass properly fit into all of those inside corners. It would be possible to bed all of the ribs in pb. Cut the stringers out after the pb has set ( this would ensure that the ribs are level). Would it be feasible to not install the stringers and fill the area with high density pour in foam to add rigidity to the hull after the ribs are glassed? It is an 18' boat with 2" tall ribs and stringers.

IF, and this is a huge IF, you could get a few others to assist you, you could mix up enough PB to PB the entire assembly in at one time. But it would take a great coordination of everybody involved. The PB would have to be mixed on the light side of the MEKP issue to allow maximum usage time before it started to kick off. But each person would have to totally understand their portion of the operation to make it successful.

If you elect to go that route, layup the assembly dry, to get an idea where all the stringers and bulkheads are to go (ribs, cross members whatever ?). Then take a sharpie and mark where everything has to go ahead of time. Then remove it and see how everybody would install it again to those markings. If you think they can get it accomplished in a reasonable time, less then 10 to 15 minutes, then start the mixing. But a would also mix a few individual amounts instead of one large amount. Reason for that is when you mix a large amount it seem to kick quicker then smaller mixtures amounts.

And once mixed, start applying the PB inside all the marker areas and install the assembly. Get it exactly where you want it and level and using a plastic filler spreader(s), smooth the overflow PB on all the sides. After you do that, leave it along until it cures. And that shouldn't be very long either. Now you see why it would take some others to help. Too much to try and do with just yourself before it kicked.

If you don't smooth or filet the overflow, it will be very hard to lay the CSM and 1708 over the irregular PB hardened material that oozed out. The smoother the wood is to the hull, the easier it will be to lay the CSM and 1708. JMHO

 

[61mysteryboat]

Are there any problems getting the 1708 to lay over the intersections of the stringers?

 

[gm280]

Are there any problems getting the 1708 to lay over the intersections of the stringers?

Of course there is a problem. The 1708 just doesn't like square corners...period. Some times you can crease the material to make it work better. But it still is a job making it lay down correctly. But by the time you are doing the tabbing effort, your stringer/bulkhead assembly is installed. So you can take a lot more time working with the 1708 tabbing for each section. Even if it took days to do the tabbing, it wouldn't make any difference in the finished tabbing portion.

Maybe some others will chime in with some additional help with tabbing 1708. It is finicky, but can be done. Since I tabbed my project boat stringers and bulkheads in place, I've came up with some ideas to try out next time.

 

[Ned L]

The cross members are not stringers, these are bulkheads.ondarvr to chime in.

Not meaning to cause any sort of a 'drift' here,..... But if we have a chance to use correct terms, the crosswise pieces would correctly be called "floors", not bulkheads.

 

[DeepBlue2010]

Not meaning to cause any sort of a 'drift' here,..... But if we have a chance to use correct terms, the crosswise pieces would correctly be called "floors", not bulkheads.

I was referring to these. The side to side members of the grid the original poster was talking about. These are called bulkheads.

And by the way, what you refer to as "floors" are correctly called "decks" in the marine world.

 

[jbcurt00]

As long as 61 understands what we're talking about, the 'correct' term isnt critical

 

[jbcurt00]

As long as 61 understands what we're talking about, the 'correct' term isnt critical

Again ^^^

And now back to our topic at hand......

Thanks

 

[gm280]

:focus:

61, I reread a few of your posts and I think you may have some things a little confused. You don' have to install the assembled stringer and bulkhead structure AND tab them in place all at the same time. You just have to PB in the assembled unit with the Peanut Butter mixture and let it cure solid. Than after all that is hard and cured, you start the tabbing efforts with the 1708 and polyester. So figure out how you want to install the stringer and bulkhead assembly first. Don't even worry about 1708 and tabbing at this point.

When you PB in the assembled unit in place, that is when you will take a spoon or whatever you like and when the PB oozes out, as it usually does some, smooth the oozed out PB to make a nice concaved fillet. Some use a spoon, some a plastic applicator, basically anything to just smooth out the squeezed out PB from under the assembled structure. The reason you do that is so when you do start tabbing with the 1708, it will lay down a lot nicer without much issue. And that is because it is not a 90 degree corner but a rounded corner.

If any of this doesn't make any sense, let me know and I will try to explain it better or even others could assist as well. JMHO

 

[61mysteryboat]

fiberglass won't play nicely



This is a replica of the original stringer assembly in my 61' starcraft. I made it just as the factory did. unfortunately it had rotted out. I pb'd the stringers to the hull today. The top of the assembly is rounded over. I raduised all of the inside corners with pb to make the 1708 lay easier. I made a mock-up of the intersection so I could see if the 1708 would conform to the corners. No luck. couldn't get the air bubbles out / wouldn't stay down. Trying to get fiberglass to conform to an X seems impossible. Is it possible to cut tabs into the cloth so sits on the top of the cross piece while draping down the sides of the other? Next, wrap the inside of the stringers. Then switch orientation to cover the tops on the next layer. I don't know if this makes sense but I hope it does. thanks for any advice.

 

[gm280]

This is a replica of the original stringer assembly in my 61' starcraft. I made it just as the factory did. unfortunately it had rotted out. I pb'd the stringers to the hull today. The top of the assembly is rounded over. I raduised all of the inside corners with pb to make the 1708 lay easier. I made a mock-up of the intersection so I could see if the 1708 would conform to the corners. No luck. couldn't get the air bubbles out / wouldn't stay down. Trying to get fiberglass to conform to an X seems impossible. Is it possible to cut tabs into the cloth so sits on the top of the cross piece while draping down the sides of the other? Next, wrap the inside of the stringers. Then switch orientation to cover the tops on the next layer. I don't know if this makes sense but I hope it does. thanks for any advice.

Okay, first thing I will say is you need to post this in the original project boat thread you already started. Once you start a thread, everything concerning that rebuild effort goes in the same thread so that followers can go to one place to see your results and offer suggestions.

Now, let's see what is going on with your fiber-glassing. Tabbing is not covering everything with 1708. Tabbing is 1708 material cut to strips about 3" wide and as long as you need them. You put the tab around the inside of the wood structure with polyester resin to hold the wood structure in place and for strength. If you were to look at a cross section of teh bulkheads and stringers, the tabbing starts on the hull and goes up the side of the wood structure like you were taping it in place.

I suggest you go to the top section of this forum and click on the "How To's and Other Great Information" thread. Then go to the list and click on #14 in the list and go to the second page and start at frame #27 and read and watch those pictures and videos of how to tab. Great info and it will show and explain what you need to do better then anything I could write. JMHO

 

[jbcurt00]

61, merged several of your topics, they all seem to cover similar ground and/or are continuations/next step in continuing project.

 

[61mysteryboat]

I appreciate all of your patience and knowledge. I don't foresee any issues with the tabbing. Those pieces are fairly simple to run from the hull up the sides of the stringers. My main concern is how I will cover the top of each rib with one continuous piece of fiberglass. I won't be able to cover the "X" with glass and be able to get all four inside corners tucked in well. Is it OK to cut the glass at the intersection to get it to fit then cover those cut edges with another layer going in a different direction? Jb had posted a drawing showing each stringer "capped" with two layers of 1708 . That would work fine if there were no intersections. Hope this helps clarify my conundrum. Thanks again

 

[jbcurt00]

Treat each compartment as an inside square box.

Get those all done and then work on capping all the intersections and top edges between the squares.

And you'll have to cut slits in the 1708 to get it fold down into each square as you run the continous cap strip.

If you glass each square up to the top rounded edge, and tab in each inner corner, the insude vertical faces are all sealed. So when you slit the cap strip and fold it down, there is no voids, unglassed or missing areas in the sealing envelope of fiberglass.

 

[61mysteryboat]

Great! Will do. That answers my question. Thanks again.