Stringer Repair / Replace

[AusMike]

Hello Forum,
Long time reader, first time poster here.

I have a project boat i'm making a start on this weekend.
The floor is out and the stringers inspected.
I have drilled in quite a few spots and the wood is dry leading me to believe the stringers are ok as far as rot is concerned.
HOWEVER, the fiberglass has de-laminated from the hardwood stringer.
Somebody has repaired these stringers previously as you can see from the colour differences in the photos.
Do you think i can use some vinylester resin to fill the voids and clamp back together? the wood is quite rough so should stick.
I was considering cutting the tops off all the fiberglass and filling. Not all of the stringers are de-laminated, maybe half.

Anyway, hoping to hear that i can get away with a repair rather than replacement.
Give me your thoughts.
Much appreciated, thanks in advance.

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[gm280]

Well first of all :welcome:to iboats. Great to have you aboard..

If you honestly want my true opinion. I see a lot of wood that may be dry presently, but certainly was soaked over the years of the hull. And if it were my boat project, I would rip out everything, grind to the good fiberglass, and replace all the wood with new quality wood and polyester resin and 1708 and CSM it all back in the usual typical fashion. But that is just my opinion. I am sure others will chime in and offer their ideas....

 

[kcassells]

Like gm said. What kinda boat is it got a pic?

 

[Chris1956]

Most of the structure looks real good. You might consider putting in some "sister" stringers and screw and glass 'em to any trouble spots.

Fill the screw holes in the stringers and glass the cut out portions.

I would brush poly resin over the entire hull and stringers, as the glass looks raw. You going to add some foam between the stringers? You should.

Install a new plywood deck. I like dry 1/2" pressure treated CDX, with stainless steel screws to hold it to the stringers.

 

[AusMike]

Hi and thanks for the replies thus far !
The boat is a Western Australian built 21ft Penguin Pacific of around 1989 vintage.
These are very solid and reputable boats around here.

I'm installing a 17mm (11/16") Ply deck sealed underneath with resin and glassed top.

Good idea coating it all again with resin, what would be the advantage of foam? I have not seen a lot of that around here.
Also, what do you mean by sister stringers? I was under the impression that this was already over engineered as to the number of stringers and their spread. There would be average of 12" between the stringers currently installed.

Again, thanks for the replies, i appreciate you taking the time.

 

[Chris1956]

Sister stringers are new stringers butted against the old. If any part of the original stringer is weak, the "sister" takes the load.

The boat may well be overengineered, however, after 30+ years, it may have some weak spots.

Installing foam can keep the boat from sinking, should she develop a leak. It is required here in the US for 60 years or so. It is only designed to keep the boat afloat. In the last 25 years, the foam is required to keep the boat upright, when swamped. Before that it was only required to float when swamped, and many floated upside down.

Also, foam is used to support the hull, between stringers and frames. It makes it real strong, with almost no weight.

In the US, a house is decked with 1/2 plywood over 16" center joists. You suggest 11/16 plywood over 12 in centers...should be overkill, IMO.

 

[kcassells]

I would think glassing to dried out glassing would be pretty useless. That would prohibit structural/mechanical
bonding. Thanks for the pics nice looking boat, appears well designed.
30 years is screaming rehab with new materials.
Foam is a def.

 

[Chris1956]

Not sure what you mean by "Dried out glassing". Resin and cloth will bond to raw wood, new or old and glass cloth, new or old. Sanding is necessary to assure clean bond.

 

[kcassells]

Not sure what you mean by "Dried out glassing". Resin and cloth will bond to raw wood, new or old and glass cloth, new or old. Sanding is necessary to assure clean bond.

IDK...from the pics fiberglass looks like resin starved.
At the end of the day I suggest a full rehab. probably one of the cleanest, open hulls I've seen to gut it out. I don't understand why not now after 30 yrs and its open/ready to go. JMHO.
The owner can do whatever he likes. It's his boat.

 

[Scott Danforth]

I would pull the existing stringers out, grind a bit on the hull, make all new stringers, tab them in properly, secure the cockpit sole, add foaming holes. foam in the sructure, plug the foaming holes, glass the top of the sole, then gel-coat

I agree the old glass looks light on resin

the wood is rotten

while at it, focus on the transom, now is the time to either keep with the old AQ drive or glass in and go with a more modern drive setup.

 

[AusMike]

Thanks for all your responses, I will take it all onboard and make some movements as soon as all this precipitation takes off. It’s winter here

all covered up but I need to get an industrial heater to get moisture content down .

will report back once I make some progress here.

thanks again !