Strip Guillemot - I've made a mistake at the stern

[ianjohnson_nz]

Hi all

I need your valued assistance! I've realised that my strips have not been following form 16 at the stern, resulting in a more rounded stern than should be the case.

I've detailed it on my blog with pictures - let me know if it is considered bad form to make y'all visit the blog, and I'll happily duplicate the post here. Here's the most relevant picture though:



I've read lots of grumbles about the Guillemot's tracking, so I'm a bit worried that a rounded stern will result in poor tracking.

My questions:
* Should I be concerned?
* If so, what best to do?
- Should I continue stripping, and later add a bit more wood in this region inside the hull, and then plane/sand it back quite a lot to gain the shape?
- Or pull these strips off, and re-glue it? (If I have to do this, what's the best way - can I soften the glue? It's standard woodworker's PVA)
- Or continue stripping as it is, and add a skeg, as Ross Leidy recommends anyway (see his article here)

Thanks in advance for your help!

Regards, Ian

[anewhouse]

Is it the same on both sides? If so then you may be able to just ignore what has happened and keep going.

In theory what should happen is that there will be a tiny bit more buoyancy in the stern, so if you sit a few centimetres further back, the trim and handling would be about the same.

I'm not sure that there is enough effect from that variation to matter.

I've found that PVA glue can be softened with about the same amount of application of the heat gun as is used to bend the strips. So if you are determined to try to restore the original shape, you might be able to heat the area while using some sort of pressure to push things back into line.

I have used that method on smaller problems.

[ianjohnson_nz]

Is it the same on both sides? If so then you may be able to just ignore what has happened and keep going.

Thanks yes it is the same both sides - while I was stripping, I didn't notice that I needed to pinch the strips inwards to make them follow form 16.

In theory what should happen is that there will be a tiny bit more buoyancy in the stern, so if you sit a few centimetres further back, the trim and handling would be about the same.

I'm not sure that there is enough effect from that variation to matter.

I've found that PVA glue can be softened with about the same amount of application of the heat gun as is used to bend the strips. So if you are determined to try to restore the original shape, you might be able to heat the area while using some sort of pressure to push things back into line.

I have used that method on smaller problems.

OK great thanks for your input, makes sense from the bouyancy point of view. What about tracking - do you think this would be a problem?

Thanks, Ian

[anewhouse]

My feeling is that there would not be a huge change in the tracking. Some other factors, like changing the weight distribution would surely have as much or more effect.

If you really want to improve the tracking or are really concerned that the tracking will have deteriorated enough to notice, there is a simple, fairly easily reversible solution.

If you are fitting an external stem on the stern, as most people do, just make the part that runs a little way along the bottom of the keel 5 or 10mm thicker than is necessary to match the original lines.

You will then effectively have a skeg about 200 -300mm long and about 5 - 10mm deep, however it is subtle enough that it doesn't look as if a skeg has been added on.

if you don't like it, you can easily plane it off and glass over it in a spot where you would probably be thinking of putting an extra layer or two of glass to protect against abrasion anyway.

I did a 5mm version of that on my wife's kayak and it makes a difference and she loves it so it has stayed and no-one has ever noticed that it is there.

I'm sure even one that size would more than get back any tracking you may have lost with the change in shape.

[Kayakkev]

On both of my Guillemots, I had the same problem, even using staples. So when I glassed the hull, I used a piece of scrap that I hot melt glued to hold the form on the inside I wanted till after the fill coats. It was easily removed when I worked the inside of the hull.

As far as tracking, I had no problem with either. I just paddled while edging to compensate. They did have a tendency to weather cock. So I did add a skeg on the second one I made for my other half at her request.

And finally I hope it is not rude to post on your blog, cause that is the only way I know how to post. LOL

KK

[Fishboy]

Hi Mate,
If you dont mind an extra small hole in a strip, You can pull it back in with a dry wall screw and heat gun, first drill a hole in the strip but do not go all the way through into the 16th form, make the hole slightly larger than the dia of the screw to be used 0.5 or 1mm, ( do this in the centre of the worst gap area), then drill the same size hole into an off cut piece of 1/2" ply wood around 20mm wide & 30mm long, to use as a washer as such & to spread the load and stop the counter sunk section of the screw biting into the hull strip, then heat along the glue line 400 mm or so while either hand screwing into the form or carefully using a battery drill pull the strip back to the form(easy does it) if you then heat the glue lines and the strips either side of that, let it cool you should find it stays in place (worked for me) just be careful not to burn the wood or over cook the glue, I had no problems so If Ican do it you can. If you find the ply wood washer is splitting due to the pressure from the screw, use a metal washer on top of the wood washer then pull it in.
Best of luck,
Fishboy

[ianjohnson_nz]

On both of my Guillemots, I had the same problem, even using staples. So when I glassed the hull, I used a piece of scrap that I hot melt glued to hold the form on the inside I wanted till after the fill coats. It was easily removed when I worked the inside of the hull.

Thanks for the reply. I am not sure I follow - is this what you're suggesting: attach a block to the inside of the stripped hull, and fix that block to the side of the form? i.e. effectively pull it onto the form?

As far as tracking, I had no problem with either. I just paddled while edging to compensate. They did have a tendency to weather cock. So I did add a skeg on the second one I made for my other half at her request.

And finally I hope it is not rude to post on your blog, cause that is the only way I know how to post. LOL

Hey no worries it's a great boost to the ego to get a post on the blog! Thanks for your suggestions.

[Kayakkev]

I personally ran a bridge under the strongback to both sides drawing it in evenly. Was worried about stripping forms. But I guess a block on the form would work as well, just have to use a little TLC when stripping it.

[Bill Raff]

What you are trying to do is create a concave surface with the strips, which is difficult to do. I tried to force the strips into place and decided it wasn't worth the trouble as long as it was the same on both sides.

[ianjohnson_nz]

Hi just to say thanks to all for your suggestions. I squeezed it after wetting and heating the region, and it seems to have worked. Thank goodness PVA relaxes when wet! I added som pictures to the same blog article linked in the first post above, if you're interested.

Actually - is it ok to wet the pva?! Have I caused myself problems down the line? It seems to be fine, the pva seems to have re-set, and certainly the timber has held the new shape. Thanks for your considered help for a newbie.

Regards Ian

[Seppy]

Ian,

the pva is only there to keep the thing all together until the glass goes on anyway, thats where all the strength comes from. So long as it seems to be holding it should be fine.

Just one question, the pic on the blog with the blocks, did you tape the bottom of the blocks? I can't tell from the photo, but at the risk of stating the obvious, always tape anything that the pva can stick to that it will touch and you don't want to be a permanent part of the boat. If you get some squeeze out under those blocks they may not want to come off again.

I often wrap some rubber bands around the hull and slide a small block under it (taped) to hold down a wayward or stubborn strip until the pva sets up.

As for tracking, my Night Heron is just as Kev described..I have to edge as I paddle to maintain a nice line, but it feels quite natural. I think in future builds like that I would include a skeg box..that way you don't detract from the look by trying to hang a rudder off it, but you can give it a little tracking assistance as well as being able to withdraw it to keep the Yak's turning ability.

[ianjohnson_nz]

Hi Seppy

Thanks yeah I did remember to tape the blocks thank goodness, they would have done nothing for the tracking! I have fair plastered the end forms in tape, But I am still a little paranoid that the boat won't separate from these as the strips are so tightly fixed around them, but fingers crossed!

[Seppy]

You're using staples right? They should separate just fine, hot glue on the other hand..don't get me started lol