FL14 (in Texas) - FINISHED!

[ks8]

Less expensive exterior ply has only 3 plies. I would suspect that it would be more likely to crack than marine grade with four or five plies. I thickened the ply of a few structures because of this when I built with exterior grade. Just a thought. If you go a little thicker on the butt block it may slightly affect the fairness of the panel bend.

Maybe if you glass the outside of the butt joint, it would help take the strain of the bend instead of it all being taken by the butt right along the seam?

My butt joints slightly opened after a week, hairline cracks in the filler. I was very concerned of the *hardspot* of strain on the butt block right along that seam, because I used exterior grade, and on my boat, the main frame that also supports the standing rigging, sit right in the middle of the butt block. If that were to crack... I don't want to think about it! I ground a little 1/16 inch channel, put in fresh filler and put biax tape over the outside of the seams and have had no problems since. If you think about it, the butt seam, if the filler cracks, has no *outer* skin strength at all without some glass over it. Marine ply may be plenty strong as a butt, but the cheap exterior these days can be scary if not compensated for a little at some critical points, imho, as an amateur. If you are using exterior, I recommend the biax tape on the outside, based on my own experience and nervousness with the same situation, only because the exterior grade these days can be so *cheap*, especially in that middle ply, and no matter how hard you try to get good panels with few or no voids, it is just hard to know what is *inside*, and the butt block seam if fairly important structurally. The butt will be a little stiffer as a result of the glass, but I don't think it will significantly alter the fairness of the panel bend.

Actually, I laminated on the biax tape while the panel was bent to shape, with the hull stitched up so the extra stiffness was fair to the intended curve.

Just some thoughts for whatever they may be worth...

ks

[MadRus]

Meranti 1088 marine ply... two boats, no voids, no cracks, no checking, no problems.

[bredstein]

Maybe if you glass the outside of the butt joint, it would help take the strain of the bend instead of it all being taken by the butt right along the seam?

Do you mean glass before assembling? Or stitch and then glass?

[ks8]

First, if good wood is used, and the plans do not specify glass on the outside, then you don't need it, because the plans and designs and wood are good.

Problem is, when using exterior grade these days, you have little control over what is *good* when it comes to the wood, unless you are going to xray the panels. So glass on the outside is very cheap insurance for the diminishing quality of interior plies in exterior grade these days.

That being said, on an FL14 I don't think it would matter if you biax the outer seam of the butt before or after assembly. But if the glass does stiffen the panel enough to cause a slight flat spot at the butt seam, and you want to avoid that minor hardly noticable condition that might not even happen, then glass the outer butt seam after the hull is stitched up (at which point you will have a slight bump from the tape!). I did it to mine after the seams were taped inside (I assembled rightside up, CV16, not FL14), and after flipping it over to upside down, but I was very careful handling it before the inside seams were taped and while flipping it, and still those butt seams developed the hairline crack from that handling, both side and bottom panels, because the butts themselves flexed more than marine grade would have.

With amateur building, the plans and assembly method and materials should compensate for professional lack of skill, and these good plans do that well. But, like I said, with an FL14, if you are concerned from the past crack experience, it is safest to biax that seam before assembly and then not worry about it! But you may get a slight flat spot which fairing compound can fill quickly when you get to that stage.

It's really not a big deal at all, but that glassing is very cheap insurance when the quality of exterior grade plywood is an unknown (it may be very good wood!).

If you ordered a kit for the build, the extra biax tape to do this was probably not in the box, so if you use what is on hand, then down the road you will come up short and need to order a bit more to finish, as I did. I have no regrets. This hull is strong now. You may want to biax the bottom butt seam also, though again, with good wood, it is not necessary if the plans do not call for it. The side panels also get strengthened when you add the rubrail, but you've already seen that unexpected things with an odd piece of bad wood can go wrong before the rubrail stage.

If I remeber right, Paul snapped a Centerboard on his CK17 that was made of good wood! A real headscratcher, unless it was a giant squid he didn't notice? But that CB may have had some unforseen weakness that made itself known quite unexpectedly.

http://gallery.bateau2.com/thumbnails.php?album=24

But that CB was not structural to the hull either. Don't worry! These are great plans. Where the wood is exterior grade, biaxing the butt seam is such cheap insurance and will add hardly any weight. Remember, enjoy the build! Smile... whistle... but not after eating crackers and working over a batch of filler ...

Sincerely,
ks

[rjezuit]

I put woven tape along the outside of the butt joints so there was a tension member on the outside wher the stress is concentrated. It worked fine and as pointed out lessened the flatness of the butt area. Rick

[ks8]

I put woven tape along the outside of the butt joints so there was a tension member on the outside wher the stress is concentrated. It worked fine and as pointed out lessened the flatness of the butt area. Rick

I don't recall Rick... did you use exterior? Got a picture of the taped seam you can link for Bredstein?

Real simple. No worries. Cheap insurance. But the kit may run short if you do it without ordering extra.

ks

[rjezuit]

I'll look for pictures, but I used BS1088 Meranti. I felt it was false economy compared to the effort, time and money I had invested in the boat/trailer/motor. The price difference wasn't that much and I had read alot of horror stories about marine fir and exterior. Rick

[ks8]

I'll look for pictures, but I used BS1088 Meranti. I felt it was false economy compared to the effort, time and money I had invested in the boat/trailer/motor. The price difference wasn't that much and I had read alot of horror stories about marine fir and exterior. Rick

Next boat intended to endure will surely be BS1088, but I hope this one to last a good long while, and its given me plenty experience *sheathing* in glass! You can still find good exterior, but it is labor intensive to find it, unless you get lucky the first time out shopping. But I do think there are some fine small boat made from it and being made from it. It certainly has a more involved learning curve, potentially. But I am all for promoting the BS1088 after my five year adventure!! My CV16 I hope to be another of those fine exterior grade boats, whether it secretly dreams it were meranti or not...

[baba101]

I used Meranti BS6566...with 3/8" 11" butt block on the bow...the joints look rock solid after nearly a week of being stretched.

I did notice the flat spots on the bow due to the wider butt block..(same as Rick) ..and plan to add 9oz woven tape to it to make it more fair..followed by fibre glass for the entire hull.

[ks8]

I used Meranti BS6566...with 3/8" 11" butt block on the bow...the joints look rock solid after nearly a week of being stretched.

I did notice the flat spots on the bow due to the wider butt block..(same as Rick) ..and plan to add 9oz woven tape to it to make it more fair..followed by fibre glass for the entire hull.

Baba,

You're slipping out of character! Shouldn't you have said...

Baba used Meranti BS6566... and...
Baba did notice the flat spots on the bow... and...
Baba plans to add 9oz woven tape to it...

ks thinks Baba's Meranti BS6566 looks great too... btw...


really...