78SN Nidacor Stringer/Floor Rebuild

I supported the hull on jack stands at the transom and keel. Then I built a set up table in the boat to lay out the stringers, cloth and misc. materials - it's worked great for me and saves me from getting in and out so often.

I used a layer of 1-1/2oz mat and another layer of 18oz roving where the double stringer secondary's are and added another layer of mat foward on the single section of the stringers. I will be foaming this area becaus I do not have to worry about any rot with Nida-Core.I am going to foam in a 5/4" x 6" pc of preasure treated board between the two double portion of the secondary grid as a screw block for a larger removable floor panel. Stick it down with a nice 4" step tab of mat, roving and mat.

Getting ready to re-string my 73 skier. What is the price difference between the nidacor vs douglas fir? How was it to work with?

Think I will stick to wood then. Would oak be a bad wood? I know Douglas is the wood of choice but my dad has oak planks that he had milled from his land and are well over 15 ft long 2 inches thick and 21 inches wide. It is good wood for most everything else structural, and it would e free to me. Just curious.
Thanks

Keeganino wrote: Getting ready to re-string my 73 skier. What is the price difference between the nidacor vs douglas fir? How was it to work with?

I am only using the Nidacor for the secondary stringers on the main stringers I am going with doug fir so I never looked at the price difference. Nidacor H8PP is very easy to work with, I have used it for 7yrs. now mostly for flooring, engine hatches, some bulk heads, deck core and a wind farring once too. The only issue with it is fasterns require some sort of insert or over bore and filling. Nidacor has a great website with lots of how too - check it out!

8122pbrainard wrote: Keegan, The only thing bad about oak is the weight. However, it MUST be White Oak (Quercus alba). Even though a stringer job includes CPES and careful epoxy/glass work, any other variety will rot if it sees any moisture. I'd sure consider the LVL if you can't find the Doug Fir.

I am pretty sure I can get it here in town, but I do not even know what to ask for to even start calling around yet. A restoration contractor I know who specializes in water damage said I should use LVL. He said he had never seen it fail(In houses not boats), and was weary of them when they first came out. I was telling him that it had been discussed on this site quite a bit, but who has done it? I guess for me it would come down to price and difficulty of working with the materials LVL is pretty easy to cut from what I understand from my friend. The nidacor looks nice but if it takes twice the glass that will kill my budget and time frame.

Are there any books out there on restringing boats that anybody recommends? I have read so many threads my eyes are popping out. I need a good old fashioned book. "Stringers for dummies" would be great!

Where in NC are you located? You could always do the floor/foam removal and have Race City do the stringers if you're not up to the task.

*edit, I love how abolton makes his own thread so he's not hijacking another and his thread gets hijacked.

65 'cuda wrote: I can tell you from experience that cutting a long radius in an LVL is not the easiest task. They are easy to cut with circular saw, but all the glue creates a lot of heat with a reciprocating blade, also the pressure on the blade tends to be one sided while cutting the arc, further heating up that side of the blade creating more tendency for the blade to "walk". Just my .02

Were you trying to use a jig/bayonet saw? That could be the problem as I really don't consider them to be a HD tool nor can you get blades made for the thicker material. A sawsall with a coarse blade (3 or 4 TPI) for roughing shouldn't be a problem and then a power hand planer will go real long way with shaping!! Of course you could also see if a friend has a band saw!

The main stringer was an easy pop out and after I cleaned the channel I did a little grind to make it bed ready for dry fit and fool proof placement. On to the Mains

That is nice work! The new pictures will really help me. Just getting started with the demo and am looking forward to being where you are at. Is that a hand planer you used to scribe? Looks like it eats some wood!

Thanks BKH. I will check those out. After reading hundreds of thread pages and some very helpful emails from the guys here, I have learned so much. My thread is Stringer Questions 73 Skier and am showing the world the mess I got into. I am pulling the engine this week and getting it down to the hull as quick as I can!

The Power Planer worked great, it was a big time saver. After I traced the old stringer I rough cut it with my skill saw then power planed it to the line. I rounded the top of the stringer with my router and a 3/4" round over bit for the glass to follow over the top easier. While the old stringer was clamped up to the new one as a template I drilled the hole for the steering cable mount and located the motor mounts points as well. Yesterday I cleaned the channel and did all the grinding needed to get ready for a dry fit and mix up some thickened resin for a 3/4" filet radius at the channel to hull. Then I will use a slurry of waterproof glass fiber filler in the channel and bed the stringer in with one layer of mat on the edge.

Yes, I used a cut off wheel to cut the skin all the way around the old stringer, it pops right out with a couple of hits with a hammer and a crow bar. First I cleaned the channel with a steel brush and acidtone then I grind the inside and I feather grind the outside thick at the bottom and thin at the top. To maket the fillet radius, just grind a 3/4" round on a plastic puddy knife and mix up a peanut butter type thickened resin, pull along the channel at the hull to make the fillet. This will ensure not air pockets when you laminate the stringer in. I round over the top of the stringer too, that way the glass gos over the top with out air pockets too.

hey eagle, whats Mr. Franken's opinion on flotation foam?

First Main made and bed in