Spindrift Gunwales

[cfergu22]

I'm having a problem attaching my gunnels to my Spindrift 10n.

I have them lined up and clamped from the bow to the stern. The problem is that part of the hull about 2 feet back from the bow sticks up higher than the gunnels. I've tried to re clamp them a few times. I know I can just plane down the hull but I wanted to get some advice before I glue everything up.

Is this normal?

Here it is mocked up so you can visualize it. Sorry they're sideways. I can't figure out how to get them to rotate when I upload them

[Hirilonde]

Do both sides of the hull match?  Does the positioning of the gunwale on both sides when dry fit match?  Measure from the chine to the top of hull and top of gunwale at various locations and verify exactly what is going on.  If I recall I had to slightly dress the hull down to the gunwale on mine.

[Alan Stewart]

It looks to me like your gunwale is too tall and is resisting being bent edge-ways. If you were careful lofting out the side panels then I would not be so quick to plane them down or the boat's sheer line won't look right or at least not as it was intended to look. 

 

I would estimate your gunwales there look to be about 1/4" x 2.5" hardwood. That's going to have a tough time bending to match the sheer line of the side panels but I think it should do. We usually make gunwales more like 3/4" x 1.5". 

 

If ANYTHING I would move the whole gunwale up by the amount you show there (the low spot) and glue it on. Then you can plane down the top of the GUNWALE to match the side panel. 

 

My 2 cents.

-Alan

[Designer]

I also felt that the gunwales look a bit deep preventing them from edge bending which they must do to follow the sheer. It is okay to plane off some of that excess ply. I like to taper my gunwales at each end for esthetic reasons. I let the gunwales stand up 1/4" above the sheer at the ends and plane the excess off later. This also reduces some of the edge bend making it easier to make the gunwale follow the sheer.

 

The sheer is one of the most important visual lines on a boat and it is worth putting some effort into making the line as sweet as you can.

[Howard]

On my 10n plans, the individual staves were shown to be 1 1/4" x 1/4". Yours look to be deeper than 1 1/4"? But as far as alignment, that part may not matter. And if allowing them to stand proud at the bow and stern and planning them to a taper is OK, then this may work in your favor.

 

I found dry fitting them was the easy part. Once thickened epoxy gets involved, handling 6 of these buttered up staves is like wrestling eels. Once you decide where the best fit is (dry fit), best to pin them in place with a screw through all three staves into the breast hook. That way, when you are ready to install them for real, you can instantly return all 6 pieces to the dry fit location.  Even with a screw anchoring them in place at the bow, I found the individual staves wanted to separate vertically, and slide up and down along the sheer, about even with to aft of the forward bulkhead. I solved that problem by clamping small 3/4" blocks along the sheer line, beneath the dry fit location of the staves. That acted as a shelf for them to rest upon so they couldn't separate. Once you get as far back as the middle bulkhead, that problem mostly goes away.

 

Two additional things to be mindful of. One is the need to work from the bow to stern by alternating side to side as you go. Unless you do that, the staves have enough "spring" in them to force one side flat, and the alternate side would then bow out, so your hull would not be symmetric and fair. Working side to side more or less shapes both sides of the hull at the same time, so the hull stays true. While all this is going on, unless you have some method of corralling the aft ends of the staves, they are going to be flying wild all over the place. I used the 4" PVC clamps and tucked the ends inside the loop near the transom. That pretty much kept them under control.

 

Additionally, with or without excessive clamp pressure, there is enough "spring" in the staves towards the bow that most of the epoxy will be forced out of the lamination. Taken to the extreme the joint will be starved and over time, the lamination may separate. (Epoxy is not like glue......it needs to gap to develop a strong bond). I was searching for a solution when I stumbled upon the idea of using fine walnut shell in the epoxy mix. It acts like a spacer to prevent squeeze out, no matter now hard you clamp it. I found 30/100 grit works the best. I would also pre-coat each of the staves with unthickened epoxy and let it soak in as much as it will take before applying the thickened stuff.

[cfergu22]

Ok Thanks,

 

Yes, you are right, the gunwales are higher than the 1.5" suggested.  They're about 2 1/8".  I hadn't considered the edge bending and since I had the width of the boards I thought I'd leave it.  They're Mahogany and I plan on leaving the Gunwales Bright so I thought it would look nice having them be a little wider. I'll cut them down tomorrow and see if that makes a difference.  I was careful when lofting and cutting out the pieces so I'm pretty sure that the sides match up.  I'll double check tonight.

 

I'll trim the boards down and see if I can get them to follow the sheer.  I'll also try to take a picture of the sheer without the gunwales on so you guys can see if they look correct.

 

Thanks for your help

 

Collin

[Joe Anderson]

I did my gunwale in two pieces so I could get the thickness I wanted and still be able to bend to the sheer with a reasonable amount of force.Some wood is considerably stiffer than others. Depending on how much time you want to spend it is possible to moisten the gunwale and let it dry thoroughly in place, you shouldn't glue if there is any moisture in the wood. That should make it easier to conform to the sheer. Be forewarned clamping the gunwale in place when it is dry is a piece of cake compared to clamping when the gunwale is all greased up with epoxy. I think I used temporary fasteners screwed from the inside through the plywood into the gunnel to keep things from sliding around.