61' Owens 18' Runabout Inside Hull Overlay Woven / Biaxial Questions

[Boatfender426]

[h=3]This is a repost from another forum in hopes I will get some info ASAP.[/h] I am wondering what would be the best layout using the the materials I have
The hull is incredibly thin and under 1/8" thick in places. ( I already cracked the hull while working inside.)
I have ground the inside and filled most of the low spots with small patches of 1708 biax and or peanut butter. The surface is still very uneven with many little dimples. I am currently grinding and attempting to smooth out the inside of the hull after doing some patch and peanut better fills.
What I have:
1) 12 yards x 51" of 1708 biaxial.
2) 25 yards x 51" of 7 1/2 oz. E-Glass woven
3) 13 gallons of Expoxy/Hardner
4) 25 yards x 12" of 7.5 E-Glass tape
5) 25 yards x 12" of 7.5 E-Glass tape

What would be the best layout sequence with what I have? 7.5 oz. E-Glass first and then 1708 or vice versa?
I am hoping to do a layer of woven plus a layer of biax over the complete inside of the hull and a layer of woven over the deck/sole.

 

[zool]

Welcome to drydock, boatfender

That mat backed biax is gonna soak up a lot of epoxy, with little benefit. You might want to just run multiple lams of the eglass, to strengthen it all up, then skim coat it all smooth with a fairing mix. If you must use the 1708, maybe lay it mat side up on the top lam, to fill the print.

 

[Woodonglass]

Yup, This ^^ is good advice. Epoxy is some strong stuff and so is the E-Glass I'd thing that to layers of the 7.5 oz E-Glass Woven finished with the 1708 Mat side up, would yield 32 oz of Fabric + alot of Epoxy. That would yield almost a 1/4" hull thickness and it would be EPOXY/Glass. Heck, I'd think that should be Plenty Good!!! But...I am just an... soo. you might not want to take my word for it!!!!

 

[Boatfender426]

Thanx for the info. Before I ordered my supplies I learned just enough to be dangerous. I thought the 1708 biax was gonna be strong so I ordered just enough
to cover the hull bottom (stringers removed) one time and enough e-glass to cover the hull bottom one time and then to cover the sole/deck one time with e-glass.. None of this will be exposed or seen when I am finished. So I am trying to make the best of my mistake and prefer not to spend to much more on glass materials.

 

[Boatfender426]

Thanx for the info. Before I ordered my supplies I learned just enough to be dangerous. I thought the 1708 biaxial was gonna be strong so I ordered just enough
to cover the hull bottom (stringers removed) one time and enough e-glass to cover the hull bottom one time and then to cover the sole/deck one time with e-glass.. None of this will be exposed or seen when I am finished. So I am trying to make the best of my mistake and prefer not to spend to much more on glass materials.

 

[Rickmerrill]

Hum, now I'm confused. I would of thought the same as Boatfender. Isin't one layer of 1708 stronger than two layers of WR? What would be the advantages of WR in this application? Can you lay multiple layers of WR on top of each other with nothing in between (does epoxy vs polyester have anything to do with it)? Is it ok to lay 1708 with the CSM side up because this is epoxy? Just trying to learn. Also, I hear e-glass all the time but isin't it what almost all of us use so that saying e-glass doesn't really add anything (unless we were talking about airplanes or high performance boats) and saying WR or CSM or cloth or biaxial tells someone what you are using and the e-glass is assumed.

 

[zool]

Hum, now I'm confused. I would of thought the same as Boatfender. Isin't one layer of 1708 stronger than two layers of WR? What would be the advantages of WR in this application? Can you lay multiple layers of WR on top of each other with nothing in between (does epoxy vs polyester have anything to do with it)? Is it ok to lay 1708 with the CSM side up because this is epoxy? Just trying to learn. Also, I hear e-glass all the time but isin't it what almost all of us use so that saying e-glass doesn't really add anything (unless we were talking about airplanes or high performance boats) and saying WR or CSM or cloth or biaxial tells someone what you are using and the e-glass is assumed.

As with most things, multiple layers laminated together is structurally stronger than one thick layer, think plywood or paralam beams, they support a longer clear span than dimensional lumber of the same nominal thickness. But strength wasn't my point, its the waste of expensive epoxy resin with the mat. Epoxy lacks the styrene to interact with the csm backing that Poly has. So essentially its just a sponge that needs to be fully absorbed. putting the mat side on top, eliminates having the weaker mat bond down in the lower section of the laminate, and at least there is a benefit of the mat filling the print.

I wouldn't go out and buy more materials over it, but the savings in epoxy waste would most likely outway the extra cost for more eglass, imo

 

[jigngrub]

Epoxy waste? I don't see that happening unless it sets up in the mixing cup outside the hull, if it goes inside the hull on the fabric it's being used. You can't add thickness and strength without putting the material in.

I'd go ahead and put the 1708 in matt side down and wet it out, wait to tack and lay the 7.5 oz on top of that and wet it out... done. Yes, you're going to use a quantity of material.... but you won't get the thickness you're looking for without it.

This is just my personal opinion and I do have an aversion to wimpy/frail boats.

 

[Rickmerrill]

Thanks Zool. I had never thought about the multiple layers being stronger, good point. Also didn't understand exactly why CSM isn't recommend for epoxy. In researching this I saw more than one source saying WR is the "most economical for raising glass content and increasing overall flexural and impact resistance without adding thickness and weight". I would have thought biaxials would have replaced WR but I'd guess most manufacturers are still building their hulls with WR. Boatfender thanks for letting me take this little diversion on your thread.

 

[Woodonglass]

Zool has hands on experience with laying fiberglass cloth with epoxy and KNOWS what he's talking about when it comes to structural strength in multiple laminations and the structural strength derived from these multiple laminations. I also know, from hours of reading and research here on this forum and talking with Resin MFG reps, that an overly thick layer of Epoxy without the addition of Fabric IS a waste of resin and while it may add additional water resistance, adds very little to the structural strength. It's the combination of the resin and fabric that gives the strength and it only requires the fabric to be adequately saturated with the resin to provide that strength. As stated Epoxy does not have styrene to break down the CSM fibers and CSM due to its make up will not add strength to the mix since it's fibers are not woven and will easily tear apart . Bulk/Thickness IS an important factor in this situation. Again, I'm in total agreement with Zool's assessment. I wish our resident Factory expert, ondarvr, (40 yrs in the business) was still active, he could really give us the low down on this and I'm 99.9% certain he'd be in agreement with Zools assessment as well. The forum is loaded with his statements that you never use CSM with epoxy and that it's a Waste to use it.

 

[Rickmerrill]

Hey Boatfender are you going to put up some pics of your project for us? Love to see the "thinnest hull on on earth". From years of researching crushing sailboats they say the older hulls usually had thicker laminations as manufacturers were still learning the structural capabilities of fiberglass laminates. I guess Owens was ahead of it's time!

 

[Boatfender426]

Wow! I am so happy to see all these posts and information! I have already started a lay of the woven so I must continue with it for the first lay on the hull bottom. I will have enough 1708 to cover the hull or deck one time but not both.(And one cover of hull or deck after this fist cover of hull with the woven.) I really don't want to use it on the deck as I believe the deck will be fine with tabbing and a layer woven.It was just tabbed and glassed before (Just glass resin rolled or brushed on). I really feel I need to use the 1708 on the hull even if I have to use a lot of epoxy to soak it thoroughly. ???
I really had to work the fabric (woven) on the first lam just to get the air bubbles out especially where it steps down the the chines/strakes. I am sure I could not have done this with the 1708 biax on the first lam. I hope it would be easier to lay it over the woven lam??
I have very limited glass experience so I am trying to make the best of my mistakes.
From what I was reading on the net, Owens small craft divisions were in turmoil in near the late 50's and early 60's. Some where during that period they had been bought out by Brunswick. ??
In all fairness the place where I stepped and cracked the hull had been repaired after scrapping some rocks in 1973'. The repair was done in Portland OR. at a decent sized repair shop.
Under the area where I removed the rotten stringer had been was filled with resin and no fiber at all so when I stepped on that spot it split open. I am surprised it lasted all these years. In the late 80's Dad and I hit a sand bar in the Columbia river while moving at a fair amount of speed with about 6 people in the boat. The force actually created a spider web crack on the front right upper bow on the outside. This is where the brace for the dashboard ties in on the inside of the bow. (I think the hull's sub structure was fairly rotten by this point and not proving it's original strength.) It also bent the prop on the 115 Evinrude and we may have came in on the 18HP. (I think we changed props on the water 'cause dad had a stainless and a aluminum and I would probably remember that slow trip back to port on the 18HP.
The boats next trip was to Ilwaco at the mouth of the Columbia river for a Chinook fishing trip. While dad was fishing he lost all power out of the 115 Rude and came into Ilwaco on the 18HP Rude. I later found the main driveshaft had sheered on the 115HP and I believe it was the impact from the sand bar that caused the main break in the shaft. It must of been hanging on by a thread. New shaft was $275 plus water pump impeller kit, seals and gaskets and no major problems on the 115 since then.
This pic is before reardown with carpet glue and resin smeared on top of the 3/4" HDO Form Plywood. It was refoamed and decked in the late 90's. But the stringers should have been replaced as well. This HDO Plywood and the CDX? kick panel at the front are in very good shape.


Getting ready to put down a lam of woven this soon...I dread this part.

Comments and pointers welcome. And thanx to everyone for your help and input!

 

[Woodonglass]

Well if you have the 1708 I guess you can use it but be prepared for it to really soak up that expensive Epoxy resin.

 

[zool]

Epoxy waste? I don't see that happening unless it sets up in the mixing cup outside the hull, if it goes inside the hull on the fabric it's being used. You can't add thickness and strength without putting the material in.

I'd go ahead and put the 1708 in matt side down and wet it out, wait to tack and lay the 7.5 oz on top of that and wet it out... done. Yes, you're going to use a quantity of material.... but you won't get the thickness you're looking for without it.

This is just my personal opinion and I do have an aversion to wimpy/frail boats.

Epoxy waste may not have been the best term, excessive epoxy use might be a better choice of words. Whether the mat is up or down will yield the same thickness, and use the same amount of material, I just wouldn't want the undesolved mat layer under the glass layer in my lams, but that's just me. In fact, I wouldn't use mat at all, but since hes got it already, no biggie. On a boat the ops size, any schedule of glass and epoxy will be more than adequate. The good thing about epoxy is its very forgiving in application, as long as the substrate is clean. There is a point of diminishing returns in the ratio tho.

Don't mean to start a resin war here, but I'm always willing to stoke the tin/glasser fire

By winpy/frail boats, you mean those tin cans floating for fluke in the channels, that I have to slalom around to get offshore?

 

[jigngrub]

Don't mean to start a resin war here, but I'm always willing to stoke the tin/glasser fire

By winpy/frail boats, you mean those tin cans floating for fluke in the channels, that I have to slalom around to get offshore?

I'm an epoxy resin guy all the way, polyester resin would have to stand on it's mama's shoulders to be able to reach up high enough to kiss epoxy resin on the butt!

Some of those tin cans may be stouter than you think, they bounce off of stumps and rocks real good where one of f'glass thingies will be lucky to make it back to the dock before it stinks... uh, er... I mean sinks!

 

[zool]

Some of those tin cans may be stouter than you think, they bounce off of stumps and rocks real good where one of f'glass thingies will be lucky to make it back to the dock before it stinks... uh, er... I mean sinks!

It only stinks for a little while when you grind out that poly hull to fix it all up like new with just the right amount of epoxy/cloth....when the tinnies hit the rip rap or pile, and get all dented up and distorted, they just paint Schlitz on the side and kick it to the curb!

 

[jigngrub]

Getting back on subject...

Whether the mat is up or down will yield the same thickness, and use the same amount of material, I just wouldn't want the undesolved mat layer under the glass layer in my lams, but that's just me.

I would think the matt side down on the 1708 would help smooth out some of the irregularities/dimples that the OP was speaking of.

 

[Woodonglass]

Getting back on subject...



I would think the matt side down on the 1708 would help smooth out some of the irregularities/dimples that the OP was speaking of.

Only if the Epoxy would break down the CSM fibers and it won't cuz it has no Styrene to do so. In this case it's only a jumbled up mess of fibers that offers little to the overall mix and therefore as Zool points out it could weaken the bond since the willy nilly structure of the fibers offer no structural integrity to the bond and could lend itself to delamination.:encouragement:

 

[Boatfender426]

Thanks to everyone on this site and on the net for their help and ideas. So far I have filled the keel with biax strips and epoxy/peanut butter. I then layed a complete layer of 7.5oz. Woven over the entire lower hull (inside). Then an additional layer of 7.5 covering from the transom forward and well into the v area of the bow. The entire lower hull (inside) was then covered with 17oz. Biaxial and approx 3.5 gallons of additional epoxy.
I should have enough woven material to completely cover the entire deck/sole when I get to that point

I did split a piece of 1 ¼” pvc pipe and laid it overtop of the keel area with peanut butter until I get it all lamed’ together with the center support stringer on top of the pipe.. This pipe is connected to the rear well with a plug and will hopefully give me a clue if there is water getting into the sub-floor area.

Mean while I have prepped the deck/sole by grinding out a couple small rotten spots and I will backfill these spots with some layer’s of biax to build it up even.
It would be nice to replace these but this has become a bucks down rebuild and I now have limited funds to play with. These are small spots and the rest of these ¾” HDO plywood pieces are in excellent shape. I filled all exiting holes and rolled two coats over the bottom with epoxy resin. They will be ready to install once I get the stringers in place.
I have two new sheets of ¾” marine plywood to make new stringers.
I am running out of Cabosil and ¼” Chop Strand. Gonna have to get some locally I guess.
This has been the longest lasting dirty job I have done yet!
It is getting better now that the hull is beefed up. Tear down and cleanup really sucked…especially the foam! And I think I am going to have about 4 gallons of epoxy plus hardener left over. Ouch!

 

[Boatfender426]

Pix of the deck pieces 3/4 " HDO and cdx kick panel.