Idea: French Drain Your Stringers?

[JaSla74]

I have this idea that has been floating in the back of my head for sometime now. I'm in the middle of my stinger/deck/transom rebuild & although I will follow the majority of advice given, it seems to me that current build practices will eventually lead to rot when using wood. We can glass til our hearts content, but water always finds a way.

Has anyone every tried/seen a setup, such as a french drain style system, that would allow water to escape from below deck? Like a 1/4" perforated pipe that ran next to the stinger that snaked out near the drain. Now obviously this could create a larger problem, but if laid properly would it work?

 

[jonesg]

Re: Idea: French Drain Your Stringers?

What about a halfpipe system?
Imagine an inverted champagne glass.

cut 3 inch pvc pipe in half along its length,
on a waxed layup table ,
wax and and resin/glass over the pipe,

pop the pipe out and you have a stringer base ,
you still need a stringer deck support on top depending on the boat design.
Vertical stringers can be made up from any of the composite materials and glassed on top of the drain system, no rot and built in drain.

 

[tashasdaddy]

Re: Idea: French Drain Your Stringers?

i have used perforated pvc pipe next to the stringer. did it help i don't really know.

 

[Mark_VTfisherman]

Re: Idea: French Drain Your Stringers?

I have this idea that has been floating in the back of my head for sometime now. I'm in the middle of my stinger/deck/transom rebuild & although I will follow the majority of advice given, it seems to me that current build practices will eventually lead to rot when using wood.

I never tried that, but I have noticed that good weep tube drains at the bottom of all the 90-degree intersections with the longitudinal (keel parallel) members are effective.

You may already know this, but, when you are glassing (I learned this the hard way the first time I repaired my transom) use epoxy not fiberglass resin. "Fiberglass resin" absorbs water unless sealed with epoxy or painted. I just won't use polyester resin anymore in places where it may be below the waterline or under floors never to be seen again. I still have "rust" bleeding through my paint in spots (from "buried" fasteners) outside the transom because I "corrected" my error but did not tear out everything I did. Didn't seem to matter inside the boat, where it is mostly dry except when fishing in the rain!

 

[DJ]

Re: Idea: French Drain Your Stringers?

The idea has been floated previously. It's a good one, IMHO. It is labor intensive thus it must be done as "custom" work.

Trapping water is one reason I am not a big fan of poured/sprayed in foam.

Boats like Boston Whaler "encapsulate" foam but that is a different process. As long as the deck remains sealed, it becomes no issue. Other boats with poured/sprayed foam are not designed to have sealed decks, thus the water intrusion.

If we let water in we must create a path for it to escape.

 

[BillP]

Re: Idea: French Drain Your Stringers?

Drains are a good idea to me but don't expect them to let all the water out. Both open and closed cell foam is a just a bunch of odd shaped capsules. Some (large numbers of them) capture water and don't drain down...unless you flip the boat over to drain. You see this over and over on project boats. Example: I had a project boat that sat about 10yrs under covered storage...bow pointed up and drain plugs open and no structure to keep water from draining...it had wet foam when I cut it up. The foam was the cheap open cell stuff that drains easily too. I don't do foam, ever.

bp

 

[ondarvr]

Re: Idea: French Drain Your Stringers?

Like Bill said, don't expect it remove all the water, plus it will give water a route to get in also. If using pour foam most (if not all) drains will be sealed by the foam, so for the most part the drain will only let water from the open end near the stern into the foamed area, not drain it out.

When using sheet foam the water will drain on it's own to the lowest point, so the drains aren't needed.

Mark VT
While polyester resin isn't as water resistant (nothing is waterproof) as epoxy it works fine when used below the water line, look at the rest of your boat, it's all polyester. Low grade polyesters may blister if exposed to water for long periods of time and an epoxy barrier coat will help prevent this from happening, but when done correctly there will be little difference in the final repair with either resin and neither will fail.

 

[Bondo]

Re: Idea: French Drain Your Stringers?

Has anyone every tried/seen a setup, such as a french drain style system, that would allow water to escape from below deck? Like a 1/4" perforated pipe that ran next to the stinger that snaked out near the drain.

Ayuh,...

It looks to me like you want to Over-engineer this thing....
I believe in KISS Engineering,...

As long as Limber Holes are put into place,.. Aka. holes Allowing water to drain to the Bilgepump....
You don't need Tubing or anything else...

Water flows Downhill,...
As long as there's opennings at the lower most point of Any compartment,...
It'll find it's own way to the Bilgepump...

 

[Mark42]

Re: Idea: French Drain Your Stringers?

What Bondo said is the simplest and most effective solution. As long as there are places along the stringers where water can drain back down to the bilge, there should be no problem, regardless of if you use polyester or epoxy.

I would cut 2" half circles along the base of the stringers between each bulkhead and also AT each bulkhead instsection of a stringer so there are no closed corners for water to pool. This will ensure that water can drain. Trying to use perforated PVC is just more effort and has its own drainage issues.

 

[Mark_VTfisherman]

Re: Polyester knowledge

Re: Polyester knowledge

Mark VT:
While polyester resin isn't as water resistant (nothing is waterproof) as epoxy it works fine when used below the water line, look at the rest of your boat, it's all polyester. Low grade polyesters may blister if exposed to water for long periods of time and an epoxy barrier coat will help prevent this from happening, but when done correctly there will be little difference in the final repair with either resin and neither will fail.

OK- I didn't know that but I believe your reference to "low grade polyesters" might be the key phrase. I had a beautiful repair- hard and clear, showing the new wood in the transom just like you were looking through glass. I'd changed the height of the transom some so put the motor on to test it before "finalizing" everything and painting. The resin turned soft, milky white, and actually bubbled away from the underlying surfaces in places.

look at the rest of your boat, it's all polyester

That I did not know either. (1972 MFG) I thought it was the same epoxy stuff the local canoe manufacturer uses to build canoes- looks like it and sands like it. So fiberglass resin from bondo is low grade...apparently?

What other stuff WILL work? NAPA has their own brand of "Fiberglass Resin" but I have used epoxy for everything since my hard, clear transom repair turned soft, milky and bubbly. Fiberglass resin is a lot cheaper than epoxy...

When I researched what went wrong with my transom, the glen-L website (which used to be a lot better than it is now) had stuff about polyester and they encouraged epoxies over fiberglass resin.

Thoughts???

 

[jonesg]

Re: Idea: French Drain Your Stringers?

Odavar will know the answer to this one.
That milky soft resin may have been due to moisture in the transom wood.
I've never experienced that, could it have been a mistake with the catalyst ?
Don't know but I've never had a resin failure in 30 yrs of playing with poly.

I don't like epoxy, it doesn't smell like victory.

 

[Mark42]

Re: Polyester knowledge

Re: Polyester knowledge

OK- I didn't know that but I believe your reference to "low grade polyesters" might be the key phrase. I had a beautiful repair- hard and clear, showing the new wood in the transom just like you were looking through glass. I'd changed the height of the transom some so put the motor on to test it before "finalizing" everything and painting. The resin turned soft, milky white, and actually bubbled away from the underlying surfaces in places.


That I did not know either. (1972 MFG) I thought it was the same epoxy stuff the local canoe manufacturer uses to build canoes- looks like it and sands like it. So fiberglass resin from bondo is low grade...apparently?

What other stuff WILL work? NAPA has their own brand of "Fiberglass Resin" but I have used epoxy for everything since my hard, clear transom repair turned soft, milky and bubbly. Fiberglass resin is a lot cheaper than epoxy...

When I researched what went wrong with my transom, the glen-L website (which used to be a lot better than it is now) had stuff about polyester and they encouraged epoxies over fiberglass resin.

Thoughts???

Yes, that MFG is a polyester resin boat. MFG's tend to hold up well, depending on model becasue the manufacturing process was quite different from one model hull to another.

Regarding the problems you had with poly, it is possable the resin was old, and it does go bad with age. Epoxy is even worse, they claim only a year and epoxy is no good.

 

[Bondo]

Re: Polyester knowledge

Re: Polyester knowledge

Regarding the problems you had with poly, it is possable the resin was old, and it does go bad with age. Epoxy is even worse, they claim only a year and epoxy is no good.

Ayuh,... I think that might be Backwards,... I Think...
I know Polyester by Any name has a pretty short shelf life...

I don't like epoxy, it doesn't smell like victory.

That's why I prefer Epoxy,...
I'll pay the price to Not have to smell the styrene...

If you buy online, the Shipping is quite abit cheaper for epoxy,...
No Haz-Mat charges...

And besides that,...
It's nearly Impossible to really Screw up a lay-up with Epoxy...

 

[ondarvr]

Re: Idea: French Drain Your Stringers?

From the brief description it sounds like you didn't use any glass in the repair, the milky color and bubbling is normally due to moisture in the wood. High humidity and moisture can stop polyester resin from curing and/or bonding.

The wood needs to be as dry as possible and glass should always be used with polyester, epoxy is a little better without glass, but for best results it should be used and is required for both on anything structural.

 

[Mark_VTfisherman]

Re: Idea: French Drain Your Stringers?

Thank you for all the good input. Just a couple of notes to clarify the repair I brought up.

From the brief description it sounds like you didn't use any glass in the repair, the milky color and bubbling is normally due to moisture in the wood. High humidity and moisture can stop polyester resin from curing and/or bonding.

Used fiberglass cloth to "extend" the transom height, two layers. Sanded and vacuumed the surfaces before starting the resin. Looked good for over a week until I got it wet. Than all the symptoms showed up.

I did manage to "harden" it back up some by heating it almost to the point of scorching with a heat gun, and then I brushed on a heavy-on-the-hardener coat of resin. After curing, I scuffed the over-coat and layed on multiple coats of paint. 5 or six seasons of steady use since then.

The wood needs to be as dry as possible and glass should always be used with polyester, epoxy is a little better without glass, but for best results it should be used and is required for both on anything structural.

I have never tried to use resin without cloth on anything structural, and I have reinforced the joints with cloth when I have used it as "glue."

Thank you again for all the insight and info here. I am learning so much cruising this forum.

 

[ondarvr]

Re: Idea: French Drain Your Stringers?

Polyester needs mat to help the bond, without it, it can be pulled off most surfaces fairly easily, so if you only used cloth that's why it bubbled off the wood. Without wax in the final layer of resin the surface cure will be poor and turning white after being exposed to water is normal, many times heating the surface will drive the water out and return it to the normal color. Polyester resin is air inhibited, meaning the surface will only cure completely if it's sealed off from it, adding wax seals it when the wax comes to the surface. This uncured resin on the surface will be soft and very sensitive to water.

 

[oops!]

Re: Idea: French Drain Your Stringers?

to the op......if you are pouring in the foam....the problem is that the foam traps the water....so even if there is pvc channels beside the stringers....the foam will still hold the water nest to the stringer.....

btw.....most un protected stringers rot because of poor drilling........that means screw holes not properly sealed......when you rip out the strings....if you catch it in itme....you will see the rot starting from the top.....where the screws are that hold the deck down.......some times you see bottom rot.....but most of the time it starts at the top....and works down the stringer.....it takes a long time for water to work "thru" a good layer of poly fiberglass........if you really want to go all out......gellcoat the stringer...!

yep....take gellcoat and paint the durn thing !....it will give you another 10 years.

BUT.....a proper replacement will give you 25 years any how.....so.....how long are you gonna keep the boat?.....


as far as white polyester fiberglass resin goes....read ondarvrs post.....polyester resin is blamed for a whole lot of stuff.......and most of it aint true.........truth is....your boat is made of the stuff.....and the resin they made you boat with ....is more than likely.....the cheapest stuff they could buy.

the land fills are full of boat hulls.......all poly resin........and the hulls are mostly still good!....its the wood stringers and transom that are rotten.