Kids build a GIS?

[CCBB]

New to the forum here, glad I found it. I am a boatbuilder here in Maine and my day job is running a non-profit boatbuilding program for at-risk youth in Maine. I would like to do a GIS with a group of kids. Should be the perfect scale and I can take them sailing after it is done. We do mostly rowboats; this would be the second sailboat.

Some questions:

1) Why not a centerboard? I know, weight. But I sort of think they are more convenient.
2) Is the board nicely faired with a NACA shape?
3) In my experience thin plywood bottoms oil can a bit underway...how is this prevented?
4) What are the estimated man-hours for the GIS minus the rig and oars.

I think Storer's lug sail is the most beautifully proportioned one I've seen, perhaps along side Oughtred's lug on his Arctic Tern. And the skiff looks pretty. I worry about the slamming that may happen, even with good helmsmanship. I don't have a lot of skiff sailing experience but some in race boats which have certainly slammed. Perhaps some can comment on the inevitable slamming problem with respect to the GIS in particular.

I'll have more Q's I am sure. Thanks.

Cheers,
Clint Chase

[CCBB]

I forgot to mention that I would hope to have kids post here as part of the build project...reading/writing/comprehension component!

[Daddles]

3) In my experience thin plywood bottoms oil can a bit underway...how is this prevented?

Proper design :D (serious answer actually, but Mik'll expand on it)

Can't answer for the other quesions. How old are the kids?

Richard

(warn 'em, we don't take kindly to SMS speak :wink: but kids are always welcome, especially when getting into building stuff :2tsup:)

[CCBB]

I don't actually have a group yet. We do over a dozen groups. The group will depend on build time required...we do semester long groups, year long groups and some short 12 weekers. I think a semester long group would do it. I want to find the right group because I will probably be the owner of the boat if it goes ahead. Kids will probably be high schoolers. One of my groups is one designed to get kids interested and trained to enter the marine industry in a highly entry level way...this would be a good project for them. We have a potential girls group too. The girls in the group tend to be cleaner and more detail oriented than the boys so this would be nice too!

Look forward to hearing from Michael. I just finished the construction photos on the site and liked what I saw.

[Daddles]

You're going to trust yourself to a boat build by a mob of kids? :oo:

I guess your main concerns will revolve around making sure it's only timber that's mutilated and timber the only thing that's epoxy encapsulated. I think the GIS is a good choice though - enough challenge to teach them something but easy and fast enough to keep that sense of achievement running. Good luck with it :2tsup:

Richard

[CCBB]

I trust a lot of kids to build boats for other customers...these are nice people who commission the boat...it is surprisingly easy to sell them the idea of sponsoring the group to build their boat...if they only saw how messy and bad the boat looked at times during construction!!! But the kids are producing professional quality boats and that is no exaggeration. It is absolutely tiring and demanding on the staff to push these high standards, but when I decided to do this work I realized that the only way to do was to do it right. Standards like getting the squeeze out, sanding with the grain, working cleanly and safely, cutting to the line and dressing up, and a very good looking roll and tip job...all these things we push hard. They never question it and I am amazed how they strive for it even the ones who have terrible ADD. Part of the problem is that they have never been held to high, authentic standards.

I say all this yet I am still nervous...I'd like the boat to come out nicely. Worst case scenario is I don't line up a group to do a GIS until next year, but it looks like the next new design to introduce. I also have to keep my staff in mind: they get a little stressed when I throw new designs in the mix, but they are starting to really know how things work...right now turnover is zero so things are looking good.

How fast can one of these boats go together, man-hours required, is the big Question right now.

Clint

[b.o.a.t.]

G'day Clint
Have you browsed the other GIS threads in this forum yet ?
eg
http://www.woodworkforums.ubeaut.com.au/showthread.php?t=22796

linked off that thread are web pages showing construction sequence & etc, including enough info to determine suitability, & plan the build.

Michael also recently did a 2-part interview for http://furledsails.com/ which will give you even more insight into the design.

Having seen BitingMidge's GIS, I cannot imagine a simpler 15' boat !
cheers
Alan J

[Daddles]

Having seen BitingMidge's GIS, I cannot imagine a simpler 15' boat !

Dunno about that, Clinton's looking at dugout canoes :wink:

Richard

[b.o.a.t.]

Dunno about that, Clinton's looking at dugout canoes :wink:

Richard

Reckon GIS would be simpler than a dug-out.
Heluvalot less hard yakka anyway. :q

AJ

[bitingmidge]

Gidday Clint,

Hopefully Michael will pop in with an answer to the build time question as he's been involved with a few "building school" projects where students have built a GIS.


1) Why not a centerboard? I know, weight. But I sort of think they are more convenient.
I assume you mean swinging type board as opposed to the dagger board? The dagger is a lot simpler and much more efficient. It's truly not a bother in terms of convenience, but they seems to be something that North Americans aren't overly familiar with from other comments I've seen. Again, hopefully Mik will expand!

2) Is the board nicely faired with a NACA shape?
Yep! It's not a NACA, a rather more modern development, and Michael has a foolproof construction method described in the plans, with templates to suit.

3) In my experience thin plywood bottoms oil can a bit underway...how is this prevented?
As Daddles said:"good design". The bottoms are 1/4" plywood and don't budge a bit. That's because every component of the structure is designed to do its bit, and reduce the span of the ply to quite small distances.

As b.o.a.t. said above, I doubt that there's a similarly sized sailing skiff with simpler construction anywhere on the planet!

Go for it!

Cheers,

P
:D

[b.o.a.t.]

As b.o.a.t. said above, I doubt that there's a similarly sized sailing skiff with simpler construction anywhere on the planet!
P
:D


Just thought of one - Bolger's Windsprint. Dispenses with frivolities such as inwales, buoyancy boxes & athwartships frames. But from what I've read of them, the bottom does oilcan, and with rather more rocker forward than GIS, they pound in a chop. They also sound slower & less stable than GIS.
I love the Windsprint plan view though. Very nearly built one rather than Teal.
AJ

[Boatmik]

Howdy Clint, I'll do a proper reply in the next 36 hours - I am working to clear a backlog of stuff.

Peter's reply covers most of the main points, but I would like to clarify a bit further.

Certainly your statement on the simplicity aspect is true. There are other boats with almost as few parts, but most don't have big buoyancy tanks, a centre seat or serious sailing performance. And most boats this size are a hundred pounds or more heavier.

Anyway ... a longer reply later. BTW did you see the PDRacers - which are cheaper to build and still sail well. If you had several groups building those you would have an instant sailing club fleet. All the building techniques are equally simple and the boats sail really well.

The big advantage is that the Goat is pretty gorgeous to look at so would be much more impressive on the builders' resumes.

Best wishes
Michael

[CCBB]

I bought the plans last night...I can have students follow these...this would be a super way to get reading comprehension going.

At this point my questions are only:

1) How does the boat handle chop...white cap, 1-2' chop beating to windward...I expect some slamming but how bad is it? (I was just at the beach watching a 20kt seabreeze kick up chop in the main channel...going across these waves on a reach I also picture it to be rough going with the waves slamming into the flat botttom...I have little skiff sailing experience so bear with me...tx!) I suspect the fineness of the bottom forward helps a lot.

2) I saw the construction pictures...it looks like this is about a 100-150 hour project...a fair estimate? I use the time estimate to plan which group builds the boat. I'd make the spars birdsmouth hollow construction, which I am used to.

I will look at your PDR racers. Have you heard of the Cape Cod Frosty class here on the East coast of US? We have a bunch of those under construction. Kids and stitch and glue is not a great combo...another reason I like the chine construction on the Goat.

I am a lug fan and have to say the BL rig and the shape of the hull work together very nicely.

I appreciate the thoughts on the above Q's and look forward to persuing the extensive instructions.

Cheers,
Clint

[Boatmik]

Some questions:

1) Why not a centerboard? I know, weight. But I sort of think they are more convenient.
2) Is the board nicely faired with a NACA shape?
3) In my experience thin plywood bottoms oil can a bit underway...how is this prevented?
4) What are the estimated man-hours for the GIS minus the rig and oars.

I think Storer's lug sail is the most beautifully proportioned one I've seen, perhaps along side Oughtred's lug on his Arctic Tern. And the skiff looks pretty. I worry about the slamming that may happen,
Clint Chase

http://farm1.static.flickr.com/126/379091257_0cf4123c57.jpg

Howdy Clint - and a proper welcome this time!

To answer your questions.

1/ The Goat Island was designed to be the simplest possible boat to match the criteria of looking kinda traditional but making use of all the technological improvements of the last century to be fast. Properly sailed it will completely outclass other classic boats.

The swinging centreboard (as we call them here - a centreboard is anything in the middle of the boat - swinging or non swinging) adds quite a lot of complication, divides up the cockpit badly (exacerbated because the floor is not particularly wide) and will just generally get in the way when moving around the boat. The daggerboard allows people to lounge around the boat a lot more easily - they can sit on the floor, the side of the boat or the mid seat when sailing. Eliminating makes the boat easier to build and easier to operate.

The camera angle here makes the boat look REALLY narrow, but you can see the simplicity and the clear space in the bottom of the boat
http://farm2.static.flickr.com/1100/875545453_cb1a2d913d.jpg

I don't like to use lead in centreboards to make them sink - it makes the boat much heavier to lift on shore or onto a trailer - and if the boat is fast the centreboard will tend to come up as you go faster unless you put quite a lot of lead in it and this requires a powerful uphaul. Or if you don't have lead a powerful downhaul. While swinging boards can be engineered so they don't leak, most are not designed that way.

The argument above is only partial - but all my boats have had dagger centreboards for the reasons above. Properly engineered there is usually very minor damage or none at all unless you hit something very hard and even then damage is very limited. Midge's waters are quite shallow and I think he has had some minor damage one time in the past five years (took me 5 minutes to fill and 5 minutes to sand the next day).

2/ NACA foil section - these were from wind tunnel testing - so the developers were guessing what was best. Now we can test the optimisation using computers and search for the best solution.

Problem with conventional sections is that for small boats they end up being too thick and wasteful of timber. The GIS rudder and centreboard are 22mm (7/8") thick. If they were a standard NACA section they would be an inch and a quarter to an inch and a half thick. This would double the labour and the materials cost and make the shaping more difficult.

I use a section developed by OZ aerodynamist Neill Pollock a few years back after running an extensive computer optimisation. The section has a shaped front and back but a parallel mid section between. This simplifies shaping because the timber blank will always sit flat on a table making it really easy to shape it accurately using the templates supplied with the plan. Undoubtedly a full NACA section would be more effective, but not a great deal more and is harder to execute with the same degree of accuracy.

Add to that the ease of shaping the Pollock section - it is probably only about 20% the labour of a "proper" NACA section - and you have a winning combination.

http://homepage.mac.com/peterhyndman/Sites/PDRinfo/PDRbuilding/buildingpics/Foils/Resources/pdrfoils016.jpeg

The use of templates is critical to getting excellent performance. Actually centreboard design is where most plans available fall down badly - most centreboard boats have serious performance downgrades because of too small centreboards - and the trend continues because everyone copies everyone else. There are few that design big enough for performance but not too big to become expensive - ones that get it right consistently are Phil Bolger and Iain Oughtred (and I imagine our own PAR! who knows a thing or three about performance)

3/ As Midge said - there is a network of support that is carefully planned but not very obvious to the casual observer. The unsupported areas are quite small. The boat doesn't pound because the bottom is so narrow at the front of the boat and I handle the back end like a modern performance skiff. Years ago they used to have big wide sterns - but the OZ skiff designers realised that there was an important balance to be achieved.

http://farm3.static.flickr.com/2046/2216137642_7d079caa2f.jpg

4/ Estimated hours are a bit difficult as it depends on who is building the boat. The Duckflat Spring School before last two men who had not built a boat before, one without any woodwork experience and one used to basic farm-style woodwork (putting up fences and building repairs I guess) put the hull completely together and built the mast in 10 days. They had my advice but worked by themselves. An experienced epoxy boatbuilding type could do better - many would do worse.

Birdsmouth mast would be OK - use the outside dimensions of the existing solid one - it doesn't shift much under use. Please put internal blocking at the partner level to prevent the mast from crushing at that point.

Rough water ... I've sailed them quite a bit - racing in Sydney against both traditional and modern boat fleets and mucking around at Mooloolaba (river, lakes and the sea) and haven't had the boat pound once. It is fast enough to launch itself off waves in really wild weather so I imagine it would give the occasional crash then - but all boats do. I'd compare the wave behaviour with just about any modern boat.

The OZ PDR is useful - not only because of the chine construction - but the rules require the boats to remain cheap - expensive gear is not allowed and sails for our rules require the sails be made of polytarp - cost $30-50 rather than pro built sails for 10 times that. Plans and instructions for the sails are in the building plan - and there is a lug rig option now.

It is not quite this big (this is the GIS rig on the PDR - done for demonstration purposes - much more wind and the mast would break)
http://farm3.static.flickr.com/2329/1717093412_b0f5b6c32d.jpg

Best wishes
Michael

[CCBB]

Thanks, I am very much looking forward to this build. She will be a boat to get me out in something more comfortable and exciting to sail than my Shellback yet big enough got my little guy and wife to go out. In the meantime I am designing the 'ideal' dayboat for us. The lines are pretty set...later this year while I build (or my students build) the GIS I'll be carefully fine tuning lines, lofting (1/4 scale) and working on the construction plan and rig (lug-yawl). As drawn at this point the Maine Coast Dinghy is 18'8" LOA x 6'6" and on the waterline 16'8" x 5'1. Freeboard is 1'7" min and 2'9" at the bow, 2' at stern with a nice cozy coaming around her. I am researching doing a steel centerboard clad in plywood to shape to a foil. Anyway this is nothing about a GIS, but I thought I'd share. I did boatbuilding school here in Maine (The Landing School) and I immediately kept teaching in my position as program director at COmpass Project (www.compassproject.org (http://www.compassproject.org)). I planned to follow up the first year with a year in design but the program was so cut throat difficult and I had a wife and infant to pay attention to. So I started drawing stuff on my own and really learned a lot when I went to Wooden Boat school to take Paul Gartside's small boat design course. With my lofting background and ability to see 3D, I took off and am really enjoying the skill of design and boatbuilding. One informs the other beautifully. Currently, I am building a norwegian faering that I drew. Would love to post a pic if that is OK.

http://img2.freeimagehosting.net/uploads/th.c2bbd11616.jpg (http://img2.freeimagehosting.net/image.php?c2bbd11616.jpg)

The gap in my fleet is a roomy, fast, handsome, quick-to-build, inexpensive dinghy with a really nice lug rig. When I found GIS, I was impressed but kept looking...what I realized later is that that flat bottom is what is going to get me to plane and have fun and build the thing for next summer. I also have the chance to do this project with a group of students which will be a test of my faith in their ability to do a good job. I am picky! But they do great work, nearly professional work to be honest and when they hear that they beam!

Cheers,
Clint

[KJL38]

Clint, I like the look of your faering, could you tell us the dimensions and weight and the thickness of the plywood you used?

thanks
Kelvin

[CCBB]

Drake is 17' 3" LOA x 4' beam. I use Shaw and Tenney outrigger oarlocks to give me the spread I need for 9' oars. On the W.L. she is 15 1/2' x 34". She is designed to row briskly over long distances and in open water. We'll see! I would estimate she will weight 125#

I used 8mil Okoume on GBD and 6mil on upper strakes. Backbone is DF and lots of Maine Spruce inside for lightness. Gunwales are Eastern White Pine. Thwarts and riser will also be EWP.

Cheers.

[CCBB]

I didn't mean to thread-jack my own post....

I am still in the process of finding a suitable group to build the Goat with me in the program for at-risk youth I manage, Compass Project.

I hope to get a group or a few kids involved -- at least some proven youth we've worked with that I know would enjoy the project -- and the rig would be useful for use in our Alpha-Beachcomber dory, which is rowing only at the time. I wish to fit it out with a lug-yawl rig.

Wil keep all posted as I sign up groups for the fall semester.

Cheers,
Clint