Thread: Start Building Another Dutch GIS

Originally Posted by Boatmik

I would have suggested just glassing the bottom then taking it round the sides rather than the extra layers of tape which (I think) just adds weight and labour without adding any practical extra strength or abrasion resistance.

Michael

I probably would have done so......but my supplier only has 1mtr wide glass cloth, and that is not sufficient to cover the chines on the widest part of the boat ( I did not order enough to use it side-way ) So I decided to use additional glass tape and will sand a part of that down to get a smooth surface and cut some weight. Not the best high-technical way to use glass-tape, but just a practical solution to use available stuff.

When I would have build a "racing" GIS, I probably would not have used glas at all , I think the wooden chines soaked in epoxy are strong enough and much stronger than any painted ply racing dinghy in the 60-70-ies?
But for my single-handed cruising I take the disadvantage of some extra weight and go for max durabililty.
I will put the hull on a scale as soon as it's ready

Howdy,

No worries at all. I see the sense of the 100mm wide tape now, normally only 25mm overlap onto the side is required, but if it saves you buying more cloth, that is great.

MIK

Originally Posted by Watermaat

When I would have build a "racing" GIS, I probably would not have used glas at all , I think the wooden chines soaked in epoxy are strong enough and much stronger than any painted ply racing dinghy in the 60-70-ies?

The glass adds little to strength in the Goat...a biax tape may add some..not sure how much is "some"...straight epoxy adds nothing to strength in the chines. When we are using glass, it is creating a matrix to help hold epoxy in around the area being treated. Unless we are using what, MIK, 10, 12+ oz biaxial boat cloth/tape, we do not begin to really add much to strength, especially when there is wood in there...cleats, chine logs, etc. that is really creating the strength.

Just a note...not a criticism here...

Originally Posted by Compass Project

The glass adds little to strength in the Goat...a biax tape may add some..not sure how much is "some"...straight epoxy adds nothing to strength in the chines. When we are using glass, it is creating a matrix to help hold epoxy in around the area being treated. Unless we are using what, MIK, 10, 12+ oz biaxial boat cloth/tape, we do not begin to really add much to strength, especially when there is wood in there...cleats, chine logs, etc. that is really creating the strength.

Just a note...not a criticism here...

You are totally right. What I meant was that soaking epoxy on any endgrain wood ( like chines on a ply boat ) improves resistance against wear ( and moist ) and therefore adds on overall strenght of the construction ( on the long run ) .
I have added extra glass on my GIS to have extra resistance against wear and abrasive forces that could be ralated to single-handed use in my area. It will not add significant strenght of the overall construction.

I have made the inwales now.
These are ( also ) slightly different from plan; I have used 27x27 mm spacers and 18 x 27 mm inwales ( cut at 30 to be planed down to 27 mm later ) .
The total inwale construction will be 45 mm wide x 27 mm high. Therefore the side-arms do not need to be tapered and are flat with the inwales.

I started with making the spacers and did a dry-fit of all parts. The spacers are held in place with a single 4x45 stainless steel screw, the inwales are held in place with clamps. Attachment 122281 Attachment 122282 .
I have placed spacers around the side-arms, the arms are notched to take the inwales. Attachment 122283 .
There are also long spacers at both ends and around the area of the rowlocks. The rest of the spacers are devided, 10cm blocks and 15 cm space where possible.
I have also notched the transom to take the inwales. This way it is much easier to place the inwales ( with extra lenght ) and finally it gives some additional strength in the wood-construction. Attachment 122284 .
After dry-fitting I have epoxy-glued all spacer blocks and fixed them with a that single screw. Attachment 122285 After cleaning and making underneath filets I have waited for 2 hours to let the epoxy cure a bit ( becomes thicker and sticky ) so the blocks could not easy be turned or moved anymore ( the stainless steel screws are left inside ) .
Than I have epoxy-glued the inwales and used clamps to fix them, so there are no visable screws or holes left Attachment 122286

NB I have fixed the spacer-block with screws to ensure sufficient strength and to be able to do things in one run; fixing spacer-blocks and inwales together.

Later things will be planed and sanded flat ( great for a beltsander ) and rounded ( with a router ) . Still LOTS of things to be planed, filled, sanded, rounded and epoxied ......but my GIS is getting closer to finishing ...

Originally Posted by Watermaat

I have also notched the transom to take the inwales. This way it is much easier to place the inwales ( with extra lenght ) and finally it gives some additional strength in the wood-construction. Attachment 122284 .

Oh, man, I need to step in and be a little devil here and say that all these slight changes appear to be better, but I am cringing at some of them. This one above is not so good an idea....can anyone guess why?

Originally Posted by Compass Project

Oh, man, I need to step in and be a little devil here and say that all these slight changes appear to be better, but I am cringing at some of them. This one above is not so good an idea....can anyone guess why?

My thoughts are that the knees have been eliminated and that could contribute to some lack of stiffness perhaps? Unless Ralph, you still have plans to install them?

I guess I did something awfully wrong ???

But I will install "knees" later . These will be ply knees, similar to the construction I have used in my Seagull design as shown in these pictures. I have also notched this transom to take the inwale. I do not see any issue here ?

End grain of inwale = moisture ingress. I did not mean to make it seem like a big deal. I was a bit frustrated with everything last night so that may have slipped through. With all your changes you have made, I was thinking that there were some boatbuilding definites...one is that it is always best to lock end-grain away under fiberglass or inside a glue joint whenever possible. Clearly the rails are an exception. No big deal.

Cheers,
Clint

Hi Clint,
You are totally right in a strickly "wooden" boat construction, but in a wood-epoxy, above waterline, trailer-sailer design . I have to admit that my ply-fir construction without the epoxy would have been a wreck within 1-2 years.......but thanks to the "E" -word it probably still floats after a few decades .
I hope you do not get frustrated about my on-going "changes" in construction?
Being an experienced boatbuilder you must agree that it's also part of the fun to make things "your way" in stead of strickly following design. I just like to "think out of the box" and find alternatives to get things done. Not always better and sometimes even worse but showing there are many ways to get beautifull wooden boats build.

Howdy,

I think that end grain is often overstated as a problem. It used to be when the timber could not be sealed effectively in some cases, but I also think it is a nicety rather than an essential.

I do think it is sensible to minimise it where possible and good building practice does cover most of that, but I've never glassed the end of a gunwale in my life. Just give it several coats of epoxy (being end grain it will soak up a bit more so will need extra coats) and then sand ready for paint or varnish.

I was surprised to see some of the details on a Pete Culler design at Mystic. Lots of end grain. I have never seen these building methods in the flesh before so it was a bit of a surprise in some ways.







sets are here Flickr: boatmik's Photostream

Not a criticism Clint, just something I was really surprised by - no crossplanked bottoms in OZ at all I don't think. Not even the Murray River Flatties which have an appropriate hullshape and construction.

Originally Posted by Watermaat

...... it's also part of the fun to make things "your way" in stead of strickly following design. I just like to "think out of the box" and find alternatives to get things done. Not always better and sometimes even worse but showing there are many ways to get beautifull wooden boats build.

As the great man himself once said:

Anyone who has never made a mistake has never tried anything new.
ALBERT EINSTEIN

That's good to see those photos of Good Little Skiff by Culler. I noticed the skiffs last time I was at Mystic but didn't get a chance to see the details.

I guess my Boat School training really comes through...we were hammered on not allowing water into the laminate anywhere...so it was full encapsulation and covering end grain whenever possible.

I think Culler's work is super important these days to help us balance off all the "epoxy-epoxy-epoxy" approach....it isn't always the answer, but sometimes you ave to choose one paradigm or the other. To mix the two ways in the same boat doesn't always work. But at the same time, as Capt. Pete said, "the old ways work". I've been studying his stuff again as I finish up a dory design that is sprit rigged (finally settled on two rigs for the client: a sprit sloop, stayed and a sprit with mizzen (yawl option) for singlehanding).

I will say that some old ways work great and one I stick with is in spars and oars: I don't encapsulate them with epoxy. I use a linseed oil varnish called Le Tonkinois and it is bulletproof and simple to use and soaks in and seal and smells great. My shop is full of the traditional smell! I'd finish off the interior of a boat with it, for sure.

Cheers,
Clint

Originally Posted by Compass Project

I will say that some old ways work great and one I stick with is in spars and oars: I don't encapsulate them with epoxy. I use a linseed oil varnish called Le Tonkinois and it is bulletproof and simple to use and soaks in and seal and smells great. My shop is full of the traditional smell! I'd finish off the interior of a boat with it, for sure.
Cheers,
Clint

As I'm about to seal my GIS's square box mast (made from Hoop pine with Paulownia infills), I am interested in your comment Clint. I was going to give it a couple of coats of epoxy to seal it and then finish with a good quality spar varnish. Also, I wanted to glass the ends and a strip at the mast partner height for abrasion resistance.