Thread: GIS in Portsmouth, NH

Spruce has a high strength-to-weight ratio so find the equivalent wood. I also like the look of Spruce when varnished.

The gunwales on a boat can be highly cosmetic. As you widen the gunwale the apparent sheer line will appear to droop, especially where the flare is greatest. This makes sense because of the angle brought on by the sheer. To correct this you get into cutting bevels to change the top angle of the gunwales. This is tricky, too tricky to explain. It involves beveling the inner rail and/or planing the top of the gunwale. The way the Goat is drawn is really the way to go. I'd bump out the width a little if you have the wood to do so, but the width is pretty good.

If you REALLY want to try something, I would build a model of the Goat and try out changes there, first. I model all my boats whether they are my own or others designs. Sometimes it is a model to check plank lines, other times it is to figure out construction, and others it is to check cosmetics. It is time consuming, but not as time consuming as rebuilding a boat to be "right".

Originally Posted by Compass Project

The gunwales on a boat can be highly cosmetic. As you widen the gunwale the apparent sheer line will appear to droop, especially where the flare is greatest. This makes sense because of the angle brought on by the sheer. To correct this you get into cutting bevels to change the top angle of the gunwales. This is tricky, too tricky to explain. It involves beveling the inner rail and/or planing the top of the gunwale. The way the Goat is drawn is really the way to go. I'd bump out the width a little if you have the wood to do so, but the width is pretty good.

If you REALLY want to try something, I would build a model of the Goat and try out changes there, first. I model all my boats whether they are my own or others designs. Sometimes it is a model to check plank lines, other times it is to figure out construction, and others it is to check cosmetics. It is time consuming, but not as time consuming as rebuilding a boat to be "right".

I see what you mean about the bevels, but I think it could work if done right. As you rightly suggest, modelling first is the solution to a full scale trial. I'm really not looking to complicating the build too much, but I think the result of flairing the gunwale slightly could be quite nice. I once rebuilt an old Sprog class (14ft design by Herbert McWilliams) hull. Pic below. These boats have a hull shape not dissimilar to the Goat but they have a deck fore and aft. Originally they did not have spray rails, but the later hulls achieved this by extending the rail, which contributed to making the boat considerably drier. In the case of the Sprog, it was simply a matter of extending the curve of the deck. Even though the Goat has no deck, I'm thinking that a slightly sloping curved rail might work quite well.

Here is a pic of the Sprog, albeit a GRP example. Note the spray rail extension and imagine this boat without it! In this case it's only about 40-50mm but the crew is getting quite a bit of extra leverage and staying a bit drier as well....


As regards pinus type timbers, we have here in Australia a plentiful supply of a lovely native Hoop Pine which is gown commercially. It's characteristics are very similar to Spruce, although much lighter in colour, and like Spruce it is a joy to work and it's easy for me to come by clear graded stuff. I have had some planks stored in my garage for about 6 years and they have been very stable....as flat as the day I bought them. Nowadays locally made Hoop Pine marine ply is superior to imported Gaboon plys, but the problem is in the sheet sizing. The sheets are only available in 1200x2400 sizes, although I see that 1200x2700 is also now becoming available! Maybe MIK might be able to confirm if the Goat could be fitted to this size sheet?
http://www.australply.com.au/about_hoop_pine.html

Paulownia is also easy to get here. It is a Chinese species that is also plantation grown here. It's very lightweight and also great for building boats. In recent times, it has become very popular with the purist surfboard fraternity and some exquisite surfboards are turned out using this timber. MIK has given it the thumbs up for incorporation into the Goat, especially for the foils. I believe that there are at least a couple of Goats that have been built with Paulownia frames. If you're interested, here is a link: http://www.paulowniatrees.com.au/english.htm

Howdy,
Great rundown WoodenEye.

So a sprog sailor .. a popular boat in South Africa.

The Hoop is a bit heavier than the spruce, but you would have to get a second (or third) mortgage on your house to get any decent stuff. The plantation hoop is fine for anything that is going to be thumped around a bit on smaller boats

The Paulownia is good for anything that is not going to be thumped around directly - so is suitable for a lot of internal cleating structure.

The goat won't fit on a 2400 sheet sadly. Problem is the side panels are quite close to each other. The other sheets would work.

However there is some reasonable Gaboon in the Country anyhow. Just have to shop around. Boatcraft have stopped dealing in it and they were a great supplier at quite cheap delivered rates. Duckflat has some nice stuff at the moment and there is a Melbourne crowd starting to make the stuff.

MIK

The 2700X1200 hoop pine ply I saw advertised tuned out to be panel ply. I was thinking that by sliding the side panels to opposite ends of a 2700 sheet it could just fit. Bummer... Would have been nice to have another option.

Originally Posted by Boatmik

So a sprog sailor .. a popular boat in South Africa.
MIK

Seems to be making a resurgence MIK. The old Sprog was not a particularly simple boat to build, so most of the ply boats (in my day they were all ply) were all professionally built. This made them quite expensive and many sailors migrated to Fireballs, which were easily and cheaply built by amateurs using stitch and glue. So the Sprog declined, but now that GRP is relatively cheap, things appear to be turning around. But a good stiff ply boat will always be competitive.

A couple of Sprog tidbits for you:

*It's a class rule that all names must begin with S

*Here is the Sprog sail logo, the bit in red anyway...

Cute idea to have the name starting with S.

I always liked the story about the S&S34 in the 1960s.

The British Prime Minister won the Sydney to Hobart in Morning Cloud. Also there was Morning Mist, Morning Sun, Morning Dew.

Until some smart alec came up with the name of "Morning All"

MIK

Bruce, I was thinking about how to do the gunwales and referred to Gartside's construction plan for a boat with the wide gunwales. He shows an inner rail with a pre-bevelled inside face. The bevel angle will dictate if the top of the gunwale is flat or slightly sloped outboard as you mention. This piece can be tapered fore and aft. Then laminations can be added to this "sponson" (that is the word he uses) to get the desired width. In another boat I have sailed, the outer most rail doesn't go the full length of the boat, it ends with a miter about a third of the way from the transom end of the boat and tapers quickly into the stem. I have a fetish for gunwales and might try to do this project, too, so we should compare notes. The key will be determining that bevel for the sponson, which can be ripped right off the table saw. I'd go maybe 10 degrees below level. It could be picked up right off the midship BHD (#3). The tops of the gunwales would need to be planed down to fair the length of the boat. Michael might be willing to help us come up with a curved template to guide the planing process, much like is used to plane the tops of the gunwales on the MSD Rowboat. I think this would make the Goat handsome, even stiffer (not that it needs it), and perhaps drier. I was truly shocked when sailing the boat with the wide, UK-style gunwales how well it knocked down spray and waves.

Cheers,
Clint

Howdy,

In the original plans the gunwales of the Goat were horizontal on top. But when I saw Peter Hyndman's Gruff with the tops of the gunwales perpendicular to the hull side I changed the plan to reflect this.

It really looks waaaay nicer.

As far as suppressing spray etc ... the goat has such a fine shape that it never kicks up much in the way of spray - I think the bottom being flat and the sides being near vertical with no transition means it is very hard for the boat to kick up spray. The bottom spits it out horizontal and low and the sides just kick it out sideways or not at all.

Could be an advantage of the flat bottom! A bit counterintuitive.

Also the boat has so much freeboard I doubt that spray will ever get up high enough to be deflected by the gunwale. Or it will be pretty rare.

I do agree with the effect of the wider gunwales on boats with lower freeboard and hull panels at angles that get water up in the air. Some of the skiff oriented kid's boats like the Flying 11 and Manly Junior that have no side decks do this very effectively too. Can look nice on the right boat as well.

MIK

"Sponson"! Now than's a word I used to hear a lot and had completely forgotten.

Thanks for that drawing Clint.

I'm making a trip to Tasmania next month where Gartside's and Oughtred's boats are quite popular, so I might take particular notes, and perhaps get some pictures of the gunwale treatments used.

I do agree with MIK that the gunwale tops look much nicer when they are perpendicular to the sides. Not only is it better looking, but I think is simpler to build too. The approach to widening the gunwale might be to simply add another rail to the outside, but my concern is that it will look unbalanced in relation to the inwale?

Hey Will, I see from your Flikr pages you're sneaking one past us! How about an update for us?

Sorry I haven't posted an updates in a while! I didn't realize how long it had been...
Since I last posted we have:

• epoxied the seats, mast step, and mast partner in place
• installed the centercase
• glued up,planed and sanded hollow box mast
• started shaping the lug and yard
• filleted seat/side edges
• epoxied in sidearms
• epoxied on gunwales and gunwale caps
• coated the inside of the hull
• epoxied in inwale spacers and inwales (will upload pictures of this soon)
• shaped and epoxied knees (will take pictures of these)

I will upload pictures of our latest progress soon (Goat Island Skiff - a set on Flickr), but unfortunately we will probably not get much more done before the winter, and out workshop/garage is not heated...

Will

Nice work there Will

We look forward to some more pics in due course

Lookin' good Will. Maybe your folks wouldn't mind you gluing up things like the foils in the warm house. You could assemble the tiller/rudder box that way too.

Clint

Particularly if the glue and assembly is done in the workshop and then the bits brought in to cure. That way large surface areas of glue will not be exposed to the air.

Actually another way with these small bits of gluing is that they are pretty flat joins so you could use one of the titebond glues which might reduce the possible complaints. You will need to use a few clamps though to get enough clamping pressure for those glues to work OK.

They need tight fits too, which is why I don't generally recommend them - but where flat framing is being glued to flat plywood there is little risk of problems as the join is about as simple as you can get and the items are small requiring only a few cramps.

Best wishes
Michael