Coronado15 Rebuild

Did the hull shift? I don't remember that the port stringer was pulled away from the hull like it appears to be now. And there's a large section of it missing?

I'll just add one more thought. The underside of your mast step (that wooden block) could easily be reinforced. When my hull was upside down, I flooded that area with epoxy (you can see where the gaps are in your image) and then put down a few layers of cloth. It ties that whole area together structurally (mast step, cockpit, stringers, the compression post, and the hull.) The boat manages huge amounts of force in this area so it pays to reinforce and tie together all the components. It is probably not necessary to replace the bulk head if that area is nicely "boxed in." And that area remains open for a future project (next spring.)

 

No sure if the hull shifted or if the stringer was cut away to remove those crazy tabs.

I remember that your goal was to go sailing this season. I'd hate to see the project get so big that you can't go sailing.

That bulkhead image from the book; even that foam spacer looks to tall to my eye. Keep in mind that you have 4 inch tape and the more spacer you have, the less tape is left over to make contact with the hull and bulkhead. You might consider ordering a small amount of wider tape and also some 10 ounce cloth.

 

Just realized, that stringer could look out of position because maybe the bottom edge was pushed out sideways.

 

I suspect that this hull has been flexing all over the place. We didn't cut away any of the stringers, but found the "missing" portion in the boat.. it was so wet it was almost dripping. I have some more pictures that reveal a bit more of what's going on inside there...I'll try to upload some later today. I suspect I will be cutting, at least some access ports in the sole near the transom at some point.. perhaps more along the lines of the access you had to cut. I 'll probably do the compression post stuff first and maybe the outer bulkhead portion...but leave the bulkhead open under the sole for now... in case I need to add structure to the keel. Plan still evolving of course.

 

Yeah, let it dry out and then box in every thing you can reach with epoxy and glass. I still think you could use some 10 ounce cloth.

 

would you go biax for greater strength?

 

Biax is very tough stuff. Yeah, absolutely I'd use it. A couple yards of 10 ounce cloth is cheap, and great to have on hand. If I was back to the point you are, I buy some biax too. Lots of it went into my centerboard and rudder; I almost think I put some into the hull (will check my pictures.) It's easy to work with as well.

OK, I just checked, I used biax every place I could. It's not always the best, because it doesn't always drape into the shape you want, but when it works, it works great. That's where cloth is good; 10 ounce is useful but you can always choose something heavier. I actually used some woven roving (I think it's a 40 ounce cloth.) I can pick up all this stuff for super cheap at my local discount marine supply store. But the prices from online sources are also very good.

 

I ordered 2 yards of 50" 9oz cloth 1 yard of 12oz 50" biax, 8 oz of silica. Even though I'm not at the stage to use these things.. I'm anxiously awaiting their arrival.

I've also noticed that using the winch to pull the boat up on the trailer, it puts a great deal of downward pressure on the deck and the forward chainplate. In fact the winch seems to pull the boat down more than forward... so I want to add an eye to the bow that is more in line with the winch. So I ordered one. ..

I still need to design and construct my compression post. Maybe I'll have some time this weekend.

 

Hello my C-15 followers,
Here's my loose plan, potential issues with regards to the compression post.
Originally, there was a strip of wood along the keel, on top of that was some type of fin, I believe to provide more rigidity to the strip of wood and to remove flex from the keel. That strip of wood I will call the "base" and the fin I call the "fin". Moving aft, we then had a compression post, I didn't save it or measure it, sadly, but I believe it to be approximately the size and shape of a 2x6. Following the compression post(CP) was a thin piece of triangular shaped plywood filling the gap between the CP and the center board trunk.

My thoughts are to replace the base with a similar shaped epoxy coated marine grade plywood base. the top side center of which will have a shallow groove routed out of it, to allow for a new 3" tall 1/2" wide fin to be inserted/epoxied in place...this fin would continue all the way aft to the centerboard trunk. I will then seek to construct a compression post out of 3 layers of 1/2" plywood but the shape rather than rectangular would conform to fill the space all the way back to the compression post. eliminating the need for that filler piece... The center plank in the compression post would be shorter creating legs, so that the CP can "straddle" the fin allowing the base, the fin , CP and hopefully the centerboard trunk to all be epoxied together forming one solid cohesive unit.



sounds great in theory right? However, I'm concerned because the bottom of the boat is not flat it's curved. So my base must be curved, so my routed channel for the fin, must be either deeper than I had intended so that low point of the channel still holds the fin in place.

Also I want to make certain the base is fully whetted (is that the right term) but I'm afraid I'll have a hard time getting the base to take the shape of the hull after I've treated the wood with the epoxy.

Also the two legged CP would have to be wet (whetted?) out and slid into place inside the boat.. which could prove to be quite tricky.

 

perhaps 3 layers of 1/2" isn't robust enough, should I go to 5? I want to keep it an odd number so that the center layer can be shorter allow for the fin slot.

 

I was thinking 5, the middle layer could fit all the way to the centerboard trunk. No big advantage to setting it into a slot. It would be cool, but also complicated. Waiting to see that keel strip cut to shape. Yeah, it should be well coated with epoxy, and the end grains especially.

 

So the center section of ply is also the "fin." The epoxy and glass is plenty enough reinforcement so that making the slot would only be extra work.

 

Sneak preview!

Base and fin, slotted and curved to match shape of the hull.




Compression post, 5 layers of 1/2" The center layer is shorter to allow fin straddle.




I still have a bit more shaping and sanding to do and I haven't put epoxy to anything yet. The whole assembly is probably still too tall for the space, and I am thinking I want to make a "cap" to go on the top of the compression post so that the through deck screws from the Mast Step aren't going into the end grain of the post.

Anyhow, stay tuned for more.

 

Looks sturdy. I see what you're doing with that fin. Much stronger than the original design. Those mast step screws are spaced apart 2 & 11/16th inches. They shouldn't grab to much of the compression post.

 

Good to know Canracer,
I did pull some plywood out though, with that big gob of what I expect was 5200, it looked like concrete(underside of mast step).. so my cap idea would replace/expand on that piece, I don't have dimensions figured out yet...still in concept phase with that.