Texas GIS

[Boatmik]

Howdy John,

Got it.

The problems is that with the added stability (power) of the Goat the loads on a leeboard and the drop in structure start to be very significant indeed.

I think it would be hard to engineer to be strong enough.

MIK

[john goodman]

We moved the GIS outside this weekend to give the garage a good cleaning and get reorganized. We cut down the old saw horses to a height of 18”. This is just the right height so the kids can get up over the gunnels and I don’t have to bend over. We have worked on the boat with the tall saw horses and while it’s on the floor and have found these shorter saw horses are just about right.
Stem Problems: There has been some discussion about the strength of the materials our stems are made of here in the forum. Mine is western red cedar and it has started to split right at the top on the port side. This is the same side were the plywood cracked at the chine log. The spilt runs vertical in the WRC about 1mm in from the plywood and down about 15mm. It is only open by .5mm or 1mm if you pull on it a little. We have added a clamp at the top to keep it from moving.
Now I am trying to figure out a fix for the problem. I will have to chisel the top 20mm off the stem since I made it too long for the breast plate design the kids and I came up with. When the breast plate gets glued in it will add a considerable amount of stability and strength. The ash rub rail will add a little tension back, since it does not bend as easy as the spruce, but the rub rail so thin that it won’t add much tension. So, it will not add to the problem.
Fix: 1.Add glass tape on the underside of the breast plate to join the plate to the plywood sides.
2. Add glass tape to the stem from the tank top up to the bottom of the breast plate.
Any other thoughts?

[callsign222]

If you haven't installed the front seat, and you want the security, you can put it another breastplate/buttress kind of thing underneath the seat to join the two sides over the stem. I almost did this. My WRC stem was super flaky and it concerned me as well. However, I have big huge fillets that run the length of the stem. This, with the seat, the bottom, and the breastplate will offer loads of gluing area to hold everything together.

[robhosailor]

Oops!
I've not observed similar problems in my current building project...
Sides of my BETH are glued to stem by epoxy mixed with silica (supported by temporairy screws) and there are filleted by epoxy and silica too:


PS: Generally elements glued by epoxy could be strong (stronger than wood's internal structure)...

[woodeneye]

We moved the GIS outside this weekend to give the garage a good cleaning and get reorganized. We cut down the old saw horses to a height of 18”. This is just the right height so the kids can get up over the gunnels and I don’t have to bend over. We have worked on the boat with the tall saw horses and while it’s on the floor and have found these shorter saw horses are just about right.
Stem Problems: There has been some discussion about the strength of the materials our stems are made of here in the forum. Mine is western red cedar and it has started to split right at the top on the port side. This is the same side were the plywood cracked at the chine log. The spilt runs vertical in the WRC about 1mm in from the plywood and down about 15mm. It is only open by .5mm or 1mm if you pull on it a little. We have added a clamp at the top to keep it from moving.
Now I am trying to figure out a fix for the problem. I will have to chisel the top 20mm off the stem since I made it too long for the breast plate design the kids and I came up with. When the breast plate gets glued in it will add a considerable amount of stability and strength. The ash rub rail will add a little tension back, since it does not bend as easy as the spruce, but the rub rail so thin that it won’t add much tension. So, it will not add to the problem.
Fix: 1.Add glass tape on the underside of the breast plate to join the plate to the plywood sides.
2. Add glass tape to the stem from the tank top up to the bottom of the breast plate.
Any other thoughts?

I think it's essential that the screws that hold the ply to the stem remain in the ply until the bottom, breast plate and the front seat elements are installed. Mick even recommended a bolt to me as I used a very soft wood (Paulownia), but it wasn't necessary. Once the bottom, breast plate and the seat elements are installed, all the stresses virtually disappear (even the nose piece would take some of the remaining stress). None of the completed Goats have reported any issues with the stem, so I think you can relax!

In stitch and glue construction, there are no stems used. All the stress is taken by the "stitches" until the bow is glassed, and the other structural elements are added.

I think that adding the extra glass as per your PDF doesn't really solve anything.

[Boatmik]

Howdy,

There is no problem once the bottom is on. The problem is that the temporary fastening goes through the ply side only at the bottom of the stem. As soon as the bottom of the boat is on it can handle huge amounts of tension - so really - don't worry.

As you probably noticed when screwing it together the load is all at the bottom of the stem with only small hand pressure required to push the top part in.

Once the bottom is on there are no problems. No need for glass, screws, cappings extra pieces of ply.

Best wishes
Michael

[john goodman]

Howdy,

There is no problem once the bottom is on. The problem is that the temporary fastening goes through the ply side only at the bottom of the stem. As soon as the bottom of the boat is on it can handle huge amounts of tension - so really - don't worry.

As you probably noticed when screwing it together the load is all at the bottom of the stem with only small hand pressure required to push the top part in.

Once the bottom is on there are no problems. No need for glass, screws, cappings extra pieces of ply.

Best wishes
Michael

We will proceed with the normal construction and not add any thing more.

[john goodman]

Had one of those "Oh Cr?p" moments tonight. Fortunately one of my sailing buddies was over and told me about the 10 Foot Rule. It involves walking 10 feet away from the boat then turning around and try to find the mistake. If you cannot find it from 10 feet away, then there is no mistake.

So look at the middle seat. If you find my "Oh Cr?p" mistake, please step further away.Make it 10 meters instead of 10 feet.

[Boatmik]

Can't see it. What are you looking at?

MIK

[woodeneye]

Had one of those "Oh Cr?p" moments tonight. Fortunately one of my sailing buddies was over and told me about the 10 Foot Rule. It involves walking 10 feet away from the boat then turning around and try to find the mistake. If you cannot find it from 10 feet away, then there is no mistake.

So look at the middle seat. If you find my "Oh Cr?p" mistake, please step further away.Make it 10 meters instead of 10 feet.

I made the same mistake with the fore/aft level. The method described in the plans didn't work for me. In my case I corrected it by removing the side seat cleats and reglueing them.

See here where I mentioned this and described how I remeasured the position of the side cleats.

[john goodman]

I made the same mistake with the fore/aft level. It is the method described in the plans I think. In my case I corrected it by removing the side seat cleats and reglueing them.

See here where I mentioned this and described how I remeasured the position of the side cleats.

You are correct.The front of the side cleats of the middle seat are too high. Visually it creates a dished or drooped look to the middle seat. Like the seat is sagging. The attached photo shows that the there is about a 5mm drop because the side cleats are too high. It bothers me too and will ponder if I have time to change. Ah hell, I know I will change it. It bothers me!

How much damage to the hull plywood is visible from chiseling the cleat off? I will need to drop mine about 5mm on each side and figure a well crafted fillet will cover any damage up. How does your fix look now after a few more days of working on it?

[woodeneye]

I was lucky that I had epoxied the sides before I attached the side cleats. After carefully chiseling the cleats off, there was no evidence. I think it would have been different had I glued them onto bare ply. However, If you just take your time and with plenty of care, you should be able to remove the cleat without damaging the ply.

I was half way to leaving mine, but decided that I could not live with it the way it was, and now I'm glad I did fix it. Can you notice any evidence of the repair?

It's an easy fix, so why not?
Attachment 135995Shesha

By the way, good to see that you haven't made another mistake that I made. I had installed the uprights on BH2 and BH4 before fitting the seats, which made the job of fitting them much harder than it needed to be. Oh well, maybe I'll get it right on the next one

[john goodman]

I was lucky that I had epoxied the sides before I attached the side cleats.
Can you notice any evidence of the repair?

Oh well, maybe I'll get it right on the next one

You picture shows no damage to the plywood. Good job!
My cleats are glued raw wood to raw wood so they will be really stuck. I will see if I can plane the cleats down before I chisel them all out.

[woodeneye]

You picture shows no damage to the plywood. Good job!
My cleats are glued raw wood to raw wood so they will be really stuck. I will see if I can plane the cleats down before I chisel them all out.

Good idea to use the plane. A small block plane is ideal for this job if you have one. Also, the slight extra gap between the seat and the side will be covered by the fillet.

[gsg270]

My cleats are glued raw wood to raw wood so they will be really stuck. I will see if I can plane the cleats down before I chisel them all out.

John, why not try the hot air gun to soften the epoxy first. It worked wonders for me a couple of times!