Thread: Son of Goat project

It is still happening in the brain at the moment. I have had the 12 footer bumped a little by a project to set up the PDRacer for simpler and faster construction.

Don't mention the PDRacer project outside this thread - I want to keep it quiet and the pressure off until the plan is ready.

Part of the reason is that Jim Michalak and John Welsford are putting together their versions of the PDRacer. The OZ Mk2 accepts some complication to keep to three sheets and push towards the best performance possible. Am thinking of a more flexible boat - with two mast positions (one for a smaller rig) an off centreboard. But the big idea is to utilise the quick canoe duct tape method to assemble - along with some hot melt glue to hold all the bulkheads and other bits in place.

This would mean all the filleting could be done in one hit and the decks added. Much simpler mast step and partner.

There is a chap starting with the prototype next week - so the race is on between the designer and builder.

However I have done some preliminaries for the 12 footer. Not happy with the sheer line yet or balance of freeboard. This image is from the absolute best angle. Things go downhill with weird sheerline shapes from other angles.


Getting the hull shape sorted is the simplest part of the design. Of that part - the marine CAD side - the slow point is as the shape is pinned down I then have to export the panel shapes and check they will fit on the ply OK without too much waste and allowing enough for the other small bits.

But this is nothing compared to the documentation!

Best wishes
Michael

As far as the boat design side of things and relating to the threads.

I will set the boat up with a static displacement to suit two people. More weight will (like the GIS) sink the bow rather than the stern so the boat will still sail well without the rocker becoming too large.

I would be guessing that the boat will be sailed single handed mostly.

I keep being tempted towards self draining, but after the RAID experience I don't really like the complication or the way the topsides go up.

Michael

Originally Posted by Boatmik

But the big idea ( for PDR) is to utilise the quick canoe duct tape method to assemble - along with some hot melt glue to hold all the bulkheads and other bits in place.

This would mean all the filleting could be done in one hit and the decks added. Much simpler mast step and partner. Michael

Do you think MIK, that this duct tape and hot melt glue approach might also be used for SoG?

Am I right to think my mainsail rig and foils would be ok to use on this hull? 74 sq ft sounds about right?

Brian

Howdy Brian,

The tape approach will only really work when there is only a small load required to twist and bend the panels. I think it might be a bit tricky with the SOG because of the twist and flare.

It might be an applicable method but I don't want to tell just anyone to try it. As I say ... I might look radical in some ways but I am a structural conservative - it is hard to move me away from what I know works.

Also have to work out what do do with the side frames.

I am unlikely to dissuade someone who wants to try though - or will try to dissuade but if it looks like they have a clear idea of what they are doing then I won't stop them.

Best wishes
Michael

Hello MIK,

Good to see other designers also picking up the PDR challenge. PDR's to rule the boating world the coming decade!

With regards to a self draining cockpit for SOG, doens't it depend a bit on what you want the boat to do? An all purpose cruising dinghy would perhaps benefit most from a deep and open inside just like the Goat.

If mainly aimed at sailing one or two-up, what about a fully decked boat with a small box cockpit like the laser, the UK topper and the sunfish (to name a few) have. Large side decks would keep the water out (as with the PDR) keeping it floating high in case of a capsize.

Just some thoughts.

Best regards, Joost

The problem with surface area is the extra weight. Having only the seat tops as the second level in the Goat saves a lot of weight.

Also from the RAID it took lots of extra time to do the under floor structure.

Michael

Hello MIK,

Yes, I fully agree. I would be in favour of a layout similar to the Goat: simple, light weight, good looking and the open interior makes it easier to take more people/gear on board and to row the boat.

But if going for self-draining, wouldn't a small cockpit only require minor underfloor structure: bulkheads at sheer height with the plywood decking going over these supported by light weight timber? Making it self draining will, I think, always come at the cost of weight increase and less handy interior. But if one wants the boat to be self draining, it is an easy solution.

Best wishes, Joost

My experience too with Raid points to favouring a Goat style interior. The kind of filled in hull and almost fully decked style that you describe sounds great but it just floats so high on it's side in the water. Raid came up after a capsize almost empty she floated so high.

So I guess for me the lesson learnt is to ensure the hull sits low in the water on her side, ensuring the mast easily floats horizontally, holding the boat steady. This also creates a rolling centre to bring the boat upright much more easily than when t floats so high.

Transom drains, or an open transom can drain a lot of the water. If somehow the design then is left with an amount of water that allows sailing to start, even more would flow out the back.

My early Scow came up with so much water, that when I open the bailer and tried to sail away, I felt I would easily plough the bows under. My later Scow with a lot of buoyancy built in, floats very high on its side and forces the mast down under the surface. It goes come up pretty dry but is then very hard to climb in. Perhaps a dinghy needs the weight of added water to help counteract the helmsman climbing back in.

My pal, with the boat righted, pushes up on the gunnel, and that forces him under water. He then pulls hard on the gunnel, which comes down to the surface water level, just as his buoyancy aid forces him up out of the water. He then rolls over the lowered gunnel and back onboard.

For what it's worth, I think SoG should be absolutely minimalist but she she also be really good looking like the Goat. Please never stop redrawing this boat until it looks special, and has the right to be called SoG.

Mind you, what do I know!! Nothing!

Brian

Thinking about the impossibilityof a boat both lying on her side low in the water and coming up with not that much water in her!!

I once owned a Norfilk Urchin



very pretty, traditional 13' dinghy that even the designer Andrew Wolstenholme thinks may be being built too heavily. She weighs 255kg! That's why I sold her, I could not pull her out of the water on her trolley on my own.

She has a lot of built in bouyancy, front, rear and side tanks. Capsize testing her it was hard to pull her over, had to work my way up the shrouds. She lay nicely on her side, very stable with wooden spars holding her very well on her side.

I righted her, but what a lot of water in her. It took me ages to bucket it all out, and that was in shallow water, not out in waves in the Solent.

So, might be tough to achieve a low immersion, and a reasonably empty boat on righting.

Sounds to me as if you would want no buoyancy in the sides so they float low, and only have the required buoyancy in a double floor. But not so much she self drains completely - that might mean free surface water would slosh around as she righted and she would immediately capsize again.

Perhaps SoG might partially drain, clear 75% or so, so she can be sailed away, so that most drains out the back but the floor is low enough to avoid too higher sides?

Brian

Originally Posted by keyhavenpotter

For what it's worth, I think SoG should be absolutely minimalist but she she also be really good looking like the Goat. Please never stop redrawing this boat until it looks special, and has the right to be called SoG.

I absolutely agree with your above statement!

A double floor would complicate the build as well as make it heavier. A simple solution to keep internal volume to a minimum might be to have rather large flotation compartments in the bow and aft and also to box in the midseat. With the standard GIS gunwales, it shouldn’t float too high in the water but water will sit low in the boat and there should be a lot less of it.

I think that SoG has the potential to become a classic (like its father) when using the same concept and design principles as behind the GIS. Being 3-4 ft. smaller, this boat will be a lot lighter and more manageable on land for one person than the Goat and easier to sail solo. It would be nice to see the same stuff that makes the Goat such an excellent craft back in this smaller boat:
- same simple and effective construction methods as used in the GIS
- very nice lines
- good performance
- versatility (the Goat is an excellent sail boat but it also rows quite nicely and can be used for cruising, raiding, camping trips, fishing etc.)
- very light weight for its size
- a lot more stable than one would expect at first sight

I understand that after your unfortunate events with Raid41 your emphasis is on a boat that is easy to board after having it righted in case of a capsize. And of course it should be given thought but I don’t think it should become the overriding criteria.

Anyway, just more thoughts that, I hope, help MIK in doing his thing.

Best wishes, Joost

P.S. I am even more ignorant than you, so our discussions here probably give MIK some good laughs!

Originally Posted by Joost

I think that SoG has the potential to become a classic (like its father) :

P.S. I am even more ignorant than you, so our discussions here probably give MIK some good laughs![/FONT][/COLOR]
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MIK has just grown a whole year older so he probably needs a laugh!!

I agree 100% with your SoG could become a classic. The Best 12' dinghy thread on the US Wooden Boat Forum came up with many lapstrake classic designs but never quite came up with a simpler purer form design.

Brian

Hi All,

SoG sounds like a great concept - a 'feral' and a 'cashmere' kid in the one litter. 12' is a great length - about the size of a sabre (my fave 12'er)- relatively easy to lift, launch and store.

The idea of camping the more-sedate-version SoG is pretty interesting. Can you do that easily in a 12'er without getting tangled in the bulkheads/frames?

Is there anyone out there who camp-cruises a GIS? Is there much of that sort of small-boat cruising in Aus? I have always liked the idea, but you don't hear as much about it here as in NZ, UK or USA.

I'm looking forward to seeing the feral version - I agree with what Mik has said previously about smooth, effortless speed, but a raw, white knuckle ride over the white horses of Loch Ness in a glen-raid sounds pretty awesome!

Jack

I am interested in camp-cruising. But my local waters (Sacramento River Delta in California does not offer much in the way of shoreside camping. Sleeping on board would be the solution but I haven't worked out how to do that on the Goat. Any ideas or suggestions would be appreciated.

My Goat gets launched this Saturday...

Shore side camping would be pretty easy with the GIS: the small light weight tents on the market nowadays don't take much space at all in the boat (nor on land). All camping gear to be stored in waterproof bags lashed down low in the boat.

Camping on board of a GIS (or the SoG for that matter) would be pretty impossible I think without making significant changes to the boat (bulkhead 3 and the daggerboard case in the way). Also, due to the open inside of the boat, it would be difficult to have a tentlike structure that would avoid rainwater to collect on the bottom of the boat.

Joost