Unintentional stringer job

[erikgreen]

Well, I just don't know when to stop digging.

I started another thread about a crooked bulkhead, and each time I thought I'd reached a point where I'd stop, it didn't feel right to do so... so I kept digging out wet wood.

I'll take some pics tomorrow, but I ended up digging out all the foam, removing the whole deck, and removing the deck cross bracing on my Sea Ray SRV-210.

Today I cut and laminated plywood for my new portside stringers and ground the hull clean... I'm replacing everything aft of the wall for the cuddy cabin on both sides. Except for the engine mounts, which I partially re-cored last summer. I'd re-do the parts I missed, but the engine is still in the boat (the parts left are hollow glass anyway, they're cosmetic).

The cuddy foam/floor is dry, although I'm still going to re-plug the foam injection holes sea ray put there.

Today I verified in a third way that my transom is good. I had knocked on it and drilled samples to verify it was dry, but today pulling off the last of the old deck a big patch of chopped mat came off to reveal pristine dry plywood.

After the stringers I'm going to install cross bracing for the deck, glue on cleats, then cut and install a new deck with lots of hatches for storage. I'll coat that with 8 oz fiberglass, and fair the edges. Then I will make a new fuel tank hatch cover.

Then maybe I can get back to installing my nautolex, which is what I started out to do a month ago!

Erik

 

[oops!]

Re: Unintentional stringer job

cheers to ya bud




lookin foward to the picks

 

[Lou C]

Re: Unintentional stringer job

Ah yes, that brings back baaaad memories, of pulling plenty of rotted wood out of my 88 Four Winns, I wound up replacing the deck from just in front of the helm seats back to the motor compartment, and having to redo some of the stringers as well....like rust on an old car...always 4 times as much as it seems at first......
It makes you wonder how well these 'no wood' composite boats will hold up after 15-20 years....let's hope better than wood n glass!

 

[erikgreen]

Re: Unintentional stringer job

Okay, pics as promised.

First, here's what I had after finishing my cleanout on the port side... I'm doing one side at a time to avoid warping.

Amidships:

And the stern, with the motor compartment/bilge 'glass still standing on the left. There's a hollow space under the motor mount, but there's nothing left in there that's wood Yep, that's my transom wood you see there. When I took out the edge of the old deck, it took a big patch of chopped glass with it, which shows me that A) I have a dry transom, at least in that spot and B) It wasn't covered with much glass.

And here are the new stringers in place:

Notes:

1) The rear stringer hasn't been coated with epoxy on the outboard side yet.
2) There's no fillet yet on the forward stringer... I want to work wet on wet where possible, but I needed to glue the rear stringer down so I did that ahead of time.
3) The rear stringer fillet is a mix of epoxy, wood flour, and milled fibers.
4) I only wiped down the immediate areas I was working in with acetone today... I'll vacuum and re-wipe before I glass. Side effect of working piece by piece rather than all at once.

I'll do the same sort of fillet on the forward stringer just before I put the glass on. I'll glass the stringers to the hull, but then I'll wait to glass them to the surrounding members until I'm farther along.

Next steps: glass the stringers down, cut the rib that mates the stringers, and place some cleats and the rib in place. Then I can start the other side at will.

Erik

 

[oops!]

Re: Unintentional stringer job

looks like yer doin just fine erik. i would have pulled the motor.....but who knows what well find....

yer kickin along pretty fast too.

good on ya

cheers bud
oops

 

[drewmitch44]

Re: Unintentional stringer job

What type of wood is that your using for your stringers? Thanks. Drew

 

[erikgreen]

Re: Unintentional stringer job

What type of wood is that your using for your stringers? Thanks. Drew

It's actually a cabinet grade interior ply... although the rear stringers one layer is dried out PT ply (I didn't have much of it). I know most people wouldn't use it due to water resistance issues, but the strength is nice - 10 layers of laminate, and no voids - and it's considerably better than what Sea Ray originally used.

I'm going to assume that if it gets wet I'll have to replace it anyway due to rot issues, so I'm designing so that it's completely encapsulated with epoxy plus I'll be able to inspect it (hatches/inspection plates).

More work tonight, I've got the other stringers laminated and the rearmost ribs done. I have to glass the portside first before I remove the starboard, though.

Erik​

 

[erikgreen]

Re: Unintentional stringer job

looks like yer doin just fine erik. i would have pulled the motor.....but who knows what well find....

yer kickin along pretty fast too.

good on ya

cheers bud
oops

I just couldn't bear to do it again right now

I replaced the motor last summer and recored all of the mounts I could reach then. The mounts are mostly composite epoxy and wood flour now, and they attach to the hull and the surrounding glass. There actually is a tiny bit of wood still in there wet, but it was a thin, hollow box that was used only to form the glass in the initial mold.

I'll probably end up redoing them sometime this year anyway, I expect I'll need to replace my coupler (it was somewhat worn) sometime toward the end of the summer.

Either that or it's a next fall project prior to whatever I do in the winter

Erik​

 

[erikgreen]

Re: Unintentional stringer job

Whew. Another evening's work done.

Tonight I:

1) Ground out any imperfections/glue spots from last time

2) Acetone cleaned my working area

3) Glued in the rearmost rib, completing the structure from stern->cuddy that I replaced.

4) Filleted the main stringer port side with a putty/glass fiber mix.

5) Applied biaxial 1708 fabric "tape" in two layers on each side to the main stringers/hull.

I didn't get the rear stringer sections done yet, maybe tomorrow.

I love the way the 1708 fabric builds up quick, is nice and sturdy to work with, and is gonna be strong as anything...but boy does it drink the resin. I used almost a whole gallon of epoxy tonight, 16 ounces at a time. Good thing I bought 5 gallons more

Pics tomorrow probably.

Erik

 

[erikgreen]

Re: Unintentional stringer job

Okay, some more progress today. Here's the pics.

Portside stringers, done with 2x layers of 1708 biaxial/mat combo:

Portside engine mount stringers, done the old fashioned way, with mat-roving-mat-roving. 24 oz roving, bought on ebay by weight as scraps. Plenty big enough pieces for this.

And finally a more centered pic of the rearmost rib joint... both Sea Rays I've taken apart had this little dogleg between the rearmost stringer section and the main stringers. The rear bulkhead for the fuel tank compartment, which started this whole mess, lines up with the rib and sits in the center of the boat, in front of the circle cut-out you see above (which is for the bilge pump).

Note that there are no limber holes in the rib... I'm making the rearmost compartment non-draining, although it will have an inspection plate in the deck and therefore a means to get water out. To have it drain into the bilge I'd have to either massively alter the hull in that area so it slopes forward or drill a limber hole or pipe hole into the engine mounts... which is a place I don't want any water. This isn't optimal, but it's much simpler, and I can change it when/if I redo the engine mounts again.

Next up I need to glass the rib/stringer joints, glass the rib to the hull, put in cleats, and start work on the starboard side.

Erik

 

[oops!]

Re: Unintentional stringer job

yeah erik....looks really good....

my sea ray didnt have the dog leg...but it did have two "box" like thingies before the bilge bulkhead....

btw.....how do you keep yer boots so glass/resin free.....


cheers
oops

 

[erikgreen]

Re: Unintentional stringer job

That's the great thing about them... they're $20 rubber boots from Fleet Farm, but any glass and resin that gets on them just peels off... it actually leaves them cleaner than if I'd washed 'em

 

[PmDavis300]

Re: Unintentional stringer job

That's the great thing about them... they're $20 rubber boots from Fleet Farm, but any glass and resin that gets on them just peels off... it actually leaves them cleaner than if I'd washed 'em

fleet farm huh? didnt realize you were in mn, are you close to the metro?

 

[erikgreen]

Re: Unintentional stringer job

Brooklyn Park, actually

I have to work on a 21 foot boat in a 23 foot garage. I love city ordinances.

 

[PmDavis300]

Re: Unintentional stringer job

Brooklyn Park, actually

I have to work on a 21 foot boat in a 23 foot garage. I love city ordinances.

oh cool, well maybe ill see you out on the water one of these days

 

[salty87]

Re: Unintentional stringer job

garage?...that's livin' it up. try hauling your junk in and out each morning/afternoon. suburban is my plywood warehouse.

 

[tmh]

Re: Unintentional stringer job

Eric, thanks so much for posting those pictures! Each stringer/deck job I see here reminds me that I NEVER want to do THAT again!!!! Yours just seemed to hit me here in the pre-season when all those memories happened last year.

Good work. The dried out PT will work fine as will the other ply. Yours looks more solid than original. IF you have a section that won't drain your idea to make it accessable is a good one! I did this and it was pleasant to check it and find it dry last year!

I left the engine in also and I do fear that someday the engine mounts will be the weak link in my boat. However, rather than fix it i think i'll part it out and buy a new to me used boat. I'll just no better what to look for the next time!

Good luck.

 

[Bill Adkins]

Re: Unintentional stringer job

Eric, these may be dumb questions but what the heck. Why did you laminate two plys of wood instead of using one thicker piece. What is the thickness of the constructed stringers and what did you use to laminate them. I am setting up to do basically the same thing so hopefully I can learn procedural benifits prior to starting. I was thinking of using 3/4 marine ply but it is 86.00 a sheet where I live so all ideas are being considered. Thanks
Bill

 

[erikgreen]

Re: Unintentional stringer job

Eric, these may be dumb questions but what the heck. Why did you laminate two plys of wood instead of using one thicker piece. What is the thickness of the constructed stringers and what did you use to laminate them. I am setting up to do basically the same thing so hopefully I can learn procedural benifits prior to starting. I was thinking of using 3/4 marine ply but it is 86.00 a sheet where I live so all ideas are being considered. Thanks
Bill

Well, let's see.

I used two plies of wood because you can't get 1.5 inch (or 40mm) plywood around here, at least not easily. Plywood used like this is something like 3x as strong as an equal thickness of dimensional lumber, and it's more uniform/easy to deal with.

It's 1.5 inches thick, and consists of 2 layers of 3/4 (19mm) interior cabinet grade plywood, which has 10 plies and no voids (air space) inside. Others would suggest using PT ply for the water resistance, but I think it doesn't matter if it stays dry... and if it got wet I'd pull it out anyway even if it was PT. The lack of voids and high ply count are similar to marine ply, which is basically just really strong plywood with no voids and waterproof glue, and is usually made from a better quality wood. To each their own wood I guess.

I laminated it using epoxy, which I got from US Composites for about $50 a gallon. The epoxy I mixed with wood flour, which is a fine sawdust I buy by the pound from bateau.com, which is a shipbuilding site. I mixed it to the consistency of creamy peanut butter, spread it on with a notched trowel, and put a weight on top of the two pieces that held them together.


I've partially coated them with epoxy, and then I used more peanut butter to glue them in place, and I also made sure that only peanut butter touched the hull.. the stringers are sitting in it. That makes sure I avoid "hard spots" which are basically just places there the load is transferred unevenly from the stringer to the hull... that's a bad thing because it means the hull would eventually crack.

Once I got them positioned and butt-joined to the existing lengths of stringer, I let the glue set. Then I roughed up the epoxy, the peanut butter glue, and the surrounding hull, wiped it down with acetone, and used more peanut butter (with added chopped glass fibers, also from US Composites) to make a 1/2" fillet between the hull and stringer. The fillet lets the fiberglass take a gentle turn in the corner - that way there are no bubbles, which are weak. Glass doesn't like sharp turns, and the thicker it is the worse it is.

I then laid two layers of 1708 biaxial glass/mat fabric down while the fillets were still wet. This was so I got a chemical (primary) bond between the fillets and the glass, which made them one piece and very strong. The glass/mat fabric is called 1708 because it's 17 oz woven biaxial cloth (heavy cloth with three sets of fibers in it... two at 45 degree angles to each other and one a third 45 away from either of those) joined to 8 oz mat. It builds up a lot of thickness and strength quickly. I technically didn't need the mat with epoxy, but it was what I had. I got it from US Composites, but I understand that scrap biaxial 1708 can be got on ebay for about $70 for a 55 pound box, and it's plenty big for this work (I've bought roving that way too).

Now that the epoxy is hard, I was able to pull the other stringer out and start on the other side. I didn't do both at once because I didn't want to risk the hull twisting at all while I worked on it. It's probably ok anyway, but nothing would ruin my day more than completing a careful repair to end up with a hull that always wants to make a left turn.

Once I finish both sets of stringers, I'll put in ribs at right angles spaced to support the floor using the same techniques... this goes beyond what was originally there, but I want a reinforced hull since I expect it to take a pounding.

I will also need to replace the fuel tank compartment bulkheads, arrange for drainage into the bilge from the forward step, and probably paint the bilge.

After that's finished I'll glue cleats onto the side of each rib and stringer top (parallel to the top edge) with more peanut butter glue. Cleats are basically 1x1 wood square poles coated with epoxy. They are attached in order to provide a better contact surface for gluing on the deck. I will then cut plywood to deck size with hatches, etc, and glue on the deck. No permanent screws involved, so no holes in my deck.

Once the wood is on, I'm going to cover it with a layer of 8 oz cloth (I have lots) and fair it with a mix of epoxy and cabosil, and also fillet the edge where the deck meets the hull.

Once all that's done, I'll install a roll of nautolex I've had sitting for two months now, and move on to installing my new doghouse and bench

Erik

 

[oops!]

Re: Unintentional stringer job

maaan that is one fantastic post!

cheers
oops