Bedding stringers???-gctid807756

[sketch96]

Getting ready to install the stringers in a 2859. The old ones were not bedded to the hull and we're wet underneath.

I've read many different ideas of whether they should float or be bedded to the hull.

Any one have any other ideas? I was thinking of bedding them in PL premium then forming fillets with thickened epoxy and glassing them in with epoxy and 1708 mat.

[SKUA_28_Contessa]

This is what I did on some of mine. In the end I don't think it matters. Some of mine were originally hard against the laminate and some had a the recommended "gap". after 25 years neither had cracked or shown any difference.

[boatworkfl]

"sketch96" post=807756 wrote:
Getting ready to install the stringers in a 2859. The old ones were not bedded to the hull and we're wet underneath.

I've read many different ideas of whether they should float or be bedded to the hull.

Any one have any other ideas? I was thinking of bedding them in PL premium then forming fillets with thickened epoxy and glossing them in with epoxy and 1708 mat.

I would bed then, I would use iso fiberglass resin, that way you can laminate the stringer to the bottom of the hull using fiberglass mat/woving combo (sewn together), with a final layer of mat-1 1/2 oz

Then gel coat it.

[builderdude]

Sketch my stringers were the same, had around a 1/4" gap. My thought on the stringer/bulkhead structure in our BL's. The structure was likely set into the hull dry, It was then blasted at with the chopper gun. My thought is that some of the copper gun material would get between the bottom of the wood structure and some didn't (mostly it didn't) .

When I replaced my engine stringer/mountings I stuck them to the hull bottom with thickened epoxy before they were glassed over.

Again, just my thoughts on why we see the gap under the structure.

[boatworkfl]

"builderdude" post=807804 wrote:
Sketch my stringers were the same, had around a 1/4" gap. My thought on the stringer/bulkhead structure in our BL's. The structure was likely set into the hull dry, It was then blasted at with the chopper gun. My thought is that some of the copper gun material would get between the bottom of the wood structure and some didn't (mostly it didn't) .

When I replaced my engine stringer/mountings I stuck them to the hull bottom with thickened epoxy before they were glassed over.

Again, just my thoughts on why we see the gap under the structure.

Some will not like this, but poor quality and quality control-$$$$ in production costs.

[sketch96]

Thanks for the replies. I will be bedding in the new stringers!

Just finished using peanut butter epoxy to fill in around the Bulkhead drains under the fuel tank area today. Going with epoxy for the whole repair due to it being waterproof and having better secondary bonding ability. I'm going to use bilge coat after I'm done.

I did already buy 5gal of poly resin and gelcoat then changed my mind. The admiral wasn't too pleased with that decision!lol.

[kwb]

I know a lot of people don't believe it but the wood in the stringers isn't all that important as long as the layup schedule gets to about 3/8" thick with at least a couple layers of roving in amongst it and it is tied into the hull well.

You do need the wood where you have something anchored to them for localized reinforcement.

[builderdude]

"kwb" post=807846 wrote:
I know a lot of people don't believe it but the wood in the stringers isn't all that important as long as the layup schedule gets to about 3/8" thick with at least a couple layers of roving in amongst it and it is tied into the hull well.

You do need the wood where you have something anchored to them for localized reinforcement.

So the wood is part of the strength then, nothing anywhere near 3/8 on mine, more like 3/16 :S

[2850Bounty]

Question: when you cut the shells open and removed the old core material, did you leave the shells in place?

.

[yachtman]

In a bayliner the wood in the stringers is necessary for strentgh. The boat has been designed as such. To do otherwise would be ruining your boat.

When it's not important it's because it's non structural.

In the past the non bedding of the stringers was the method as to not make hard spots structurally so the hull didn't break apart at flex and non flex areas of the glass.

However more recent thinking is to bed them. One problem of non bedding is the air space between the glass and the wood. However small that air space creates condensation which in turn makes the wood wet which can create rot.

Bayliners past construction in many cases woefully inadequate in regards to stringers. ( was the technology of the time not bayliners fault others did it too) Poorly glassed poorly covered. No joint scarf and the stringers were never isolated as to prevent rot from spreading throughout the entire boat.

All the bare raw wood in my 32 ft touched somewhere and at some point so if I got rot in the transom it could literally travel all the way to the bow.

The worst part of the construction was that the bulkhead stringers and walls were only tabbed in and many got rot from being wet above that 3 or 4 inches of tabbing. That rot then infected the stringers because the bulkhead were in direct contact with the stringers.

Thus the tabbing in of the stringers wood would leave me to believe that indeed the wood in a bayliner in fact is structural and not the glass it's self.

That much glass would make the boat heavy and very unaffordable if you want to change how the stringers give support in a bayliner you will also need to change other things such as how bulkhead are installed, the hull thickness and deck and hull joints. It's not really worth it to change it otherwise.

One thing I have learned in boats when something is changed no matter how small it effects other parts or sections of the boat. If you change how the stringers are installed then you must change other things also. ( I don't believe this is the case for bonding though).

The engines are bolted to this stringers that in turn transfers that force fore and aft of the boat any time you make the stringers different (weaker) you must also strengthen other parts of the boat

[sketch96]

Good info. Thanks! I only removed the shorter stringer. The one that runs from the transom just up to the aft Bulkhead for the fuel tank. It sisters up to the longer stringer that runs from the transom all the way up under the fuel tank. I left one side of the shell that the stringers were encased in, removed the other side that allowed me to remove the shorter inner stringer.

Everything has dried out nicely now and I will be able to squeeze in some thickened epoxy in the gap under the longer stringer before bedding in the shorter stringer. I will also screw and epoxy that stringer to the longer stringer. I will also screw and epoxy the motor mount humps back on this time. Should not be any voids to allow moisture in I'm hoping.

The old humps were made of 2 2x4 nailed together on end. They then stapled a piece of 3/8 plywood on top then glassed them in. On one side they put a 3/8 plywood shim between the motor mount and the hump. Like it wasn't tall enough so they had to shim it. Seems rather cheap. I'm thinking of just building the hump slightly taller to make up for this and eliminating the shim. EDIT: The old humps were one piece of 4x4 that is 3 1/2" wide. It sat on the 3" wide double 2x4 stringers. I couldn't figure out why the fibreglass was bulged out funny where the humps attached to the stringers until I tore it all apart. The new mounts I made are 2 2x4 on end with a piece of 1/2" plywood sandwiched in between. I ripped a 1/4" off one of the 2x4 so I now only have 1/4" difference in the width instead of the 1/2" it had from factory. Should glass over a little nicer thus time.

Right now I'm just coating all the new wood for the fuel tank bed before glassing it all into the boat. Tank should be done this week sometime. Something I didn't see when removing all the old rotten wood from under the tank was that the fuel tank bed sits with a slight angle to it. The runners for the bed directly under the tank have a taper cut into them. Not sure which way to angle the tank? I'm thinking higher at the front so that fuel is always around the pickup but this may cause slight under filling of the tank when fueling? Any thoughts?

[builderdude]

I would think the same, tank a bit higher in front. Maybe a pm to Fritz on that one.