Thread: Hello, new GIS build by Simon in ST Pete FL

My plans were one of the first sold in PDF format and I recall an anomaly in the measurements in that area. It was so obviously wrong I emailed MIK and he sent the corrected offsets. I'm wondering if you have got hold of the old plans...Either way you should hold off making any cuts until you get it sorted out. Once I had the correct offsets I had no problem getting the batten to lay true.

Howdy Simon,

That slight hollow is correct.

The test is to see if there are three or four nails that agree with each other - which they do.

Errors will almost always be random ... only one nail wrong.

MIK

Hi Mik,

Ah yes, its called a hollow. It puzzled me a bit but sounds like all is good.
Many thanks for watching these threads and answering our newbie questions.

Simon, Just an FYI, because the line goes hollow doesn't mean that it is unfair. When you pull the batten into those points, get down sight down the length of the batten (make sure the batten has no kinks to start with) and look for that eye sweet, gentle flowing curve. If it looks good and you are off a few points by a few mm's you are OK!

If you know what a fair line looks like, and you can get that batten fair, that is all that matters. The key points to hit are bow, stern and midship points and then making sure to hug those points that make the slight hollow. Sight down the lines on the plans drawing (which I like to be bigger than they come...blow them up in size to 11 x 17") and where you see a hollow in the drawn lines there should be a hollow in the full size lines. There is interpretation involved for sure, but get the nature of the full size line to mimic the drawn line, make it fair, and when it looks good and you're hitting those key points I mentioned, then draw the line and cut!

Be sure the cut line is square...the skilsaw or jigsaw or whatever is squared up and the base plate of the tools stays flat on the ply so the cut is square...then you are not changing the nice fair line you drew out.

Cheers,
Clint

Hi Clint, thanks for the explanation, it helps. I'm lucky to have a friend building an 18 foot strip kayak alongside my GIS build so I have a ton of absolutely clear 20' battens to use

The offsets, drawn from the plans, are as perfect as one could hope for. All of the nails either touch or are within 1mm of the batten's fair curve. The hollow in the sheer at the bow made sense to me. That shape, when the sides are twisted around the bulkheads forms the beautiful sheerline. But I was a bit concerned about the slight hollow in the bottom by the transom. I guess it's all part of that magical hull shape everyone raves about. And yes the hollow is perfectly fair.

I had forgotten that hollow but I just printed the page and you can see it when you sight along the line as Clint suggested. It reminds me of how the bottom runs on the famous Simmons Sea Skiff. When Dave Carnell bought an old Skiff and started taking the lines off he thought the stern might be a little hogged so he asked Mr. Simmons about it. Simmons reply was, "my boats don't hog. That is there on purpose." It is apparently a key feature that gets the SSS up on plane quickly without having to stick her nose in the air first. It's probably doing the same thing for the Goat.

I bet you are right. Keeps the stern up, a bit like a trim tab.

Building has been slow lately. I ran into some plywood problems which I will post about soon.

I am working on the centerboard and noticed that if I add up all of the stave widths in the materials list on p12 I get a width of 370mm but the drawing on p63 shows a width of 341mm. What am I missing?

The stave widths are approximate, for planning and ordering of the lumber. They can actually be of most any width as long as you end up with something wide enough to give you the final size.

Hi MAM, Maybe I'm being dense, but I'm still confused. I understand that the stave width and number is arbitrary as long as they all add up to the correct centerboard width. So lets use the rudder as an example. All of the stave dimensions on the materials list add up to 260mm. This matches the rudder width dimension of 260mm from page 63 of the plans.

Now when you do the same calculation for the centerboard you get 370mm and 341mm respectively. So that's where my confusion comes from.

How wide should the board be?

HI Simon,

You do need a minimum width of 341mm to make the board. However because of timber sizes you won't match that exactly when ordering. So any timber that gives you that size or larger will be OK.

You have to follow the drawings when you make the centreboard and rudder of course.

A common size for timber in Australia is about 45mm, though it might be closer to 41 when finished - there is no real standardisation - so someone can order off the timber list and it can be too narrow.

The extra bit guarantees that there is something there to make either the centreboard or the rudder a bit wider if they come in under size when the timber is delivered.

MIK

Some nice things on your Blog Simon!

MIK

Hi Mik,

341mm it is!

Thanks for the blog compliment. I'm a month behind, gotta get on it.
I moved to St Petersburg on Tampa Bay (Gulf coast of Florida) two years ago.
There is a very vibrant small boat community here.

I have now been through the plans a bunch of times and I can't, for the life of me, find the page with the rudder and daggerboard templates.

I have the page with the big "Sample only read note at top" print but not the actual template page.

And I don't think I'm missing a plans page because they are numbered and easy to spot.

Anyone have any idea what's wrong? Thanks