Thread: Son of Goat project

Howdy

Remember it takes a lot of time to do all the documentation from this point. But first glimpse.

Spent the weekend fissling with the shape. It was a bit of a struggle. I think I was spooked by how nice the Goat looks, How to create a successor?

I don't know how many versions I have checked. The first shorter version of the Goat was drawn up years ago.

Anyway it looks like it fits on the ply, a couple of things to resolve structurally as well But feeling happy and confident about this version.

The sail is not the PDR one as I had hoped to use the two sails directly, but is a bit higher aspect. The PDR sails just didn't look right as the aspect ratio was too low. But can use the mast, yard, centreboard, rudder and rudderbox.

MIK

Originally Posted by Boatmik

I think - she looks interesting: simple classic elegance

Hello MIK,

The profile is looking very nice! The tallish rig seems to fit the boat rather well.

It looks like that this boat has sailing solo high on the agenda: one big cockpit!

Three questions:
- main dimensions (lenght, width, weight and sail area)?
- do I understand correcty that the boat is fitted with 2 decks (one aft deck and one front deck) without any midframe?
- will the "sides bending around the frames" method of the GIS work here?

Best regards,

Joost

The proportions look spot on to me Mick. A very handsome looking boat and there's no doubting its genes.

Extending the deck to behind the dagger board case is brilliant. I guess with it's dimensions we can call this tank top/seat a true "deck"? Just one design question... Will water run off that deck expanse OK?

Is the length about 12'? Looks something like that from this first look.

Keep going. This is looking quite special already!

Howdy,

The length to the bottom of the bow is 12ft, with an extra inch length at the top to prevent the bow leaning back appearance the Goat occasionally gets.

Beam - 1452mm (4ft 9")
I would be estimating hullweight to be about the 120lb mark.
Sail area in this pic is 7.2sq m (78 sq ft) but I think like the Goat it would be sailed reefed some of the time.

The dagger board was a way of getting a rowing seat but still allowing enough room for a second person as well as allowing the crew to cram forward in light winds. It was the easiest part .. I drew in the centrecase and the rowing seat quickly as it seemed obvious even though I hadn't imagined it a couple of minutes before.

MIK

Hi MIK

she look's sweet.

Like the front and rear tanks. Keeps free water in the centre of the boat. Rowing seat great idea. perhaps stow oars along centre line? Might be a bit in the way but make great "toe straps". Helm could even sit on them for a central mid point downwind position.

I sit on the thwart solo sailing nearly all the time. From central downwind to further out and then bum over the gunnel as the wind increases. As the wind drops a bit I lower myself from gunnel to thwart. How does that work on these gunnel and no side seat, no thwart boats?

Love the higher peak yard - looks just right.

Proportions are nice. Looks like she will plane early.

Perhaps she will lay on her side nicely on a practice capsize and come up with not too much water. Just enough to steady her as crew climbs in, then bails her fairly quickly.

What ply estimation are you looking at? Does construction steal anything from these quick canoes or is it pure Goat style?

Terrific upgrade for a PDR sailor looking for their next boat. Using the same spars in the new higher aspect rig is very clever.

Brian

Great point about the intermediate sitting position when coming off the gunwale. Will think through and reply to everyone when i get a bit more time later in the day.

Ply looks like 5 sheets. Bottom and sides and a couple of other bits come out of three sheets of 6mm.

Then two more sheets for all the internals could be 4mm.

Construction is imagined as pretty similar to the Goat. Still like the way the chine log makes everything so perfectly fair. The Quick Canoe method really is a compromise - a worthwhile one for a fast building boat.

MIK

Originally Posted by Boatmik

Howdy,

The length to the bottom of the bow is 12ft, with an extra inch length at the top to prevent the bow leaning back appearance the Goat occasionally gets.

Beam - 1452mm (4ft 9")
I would be estimating hullweight to be about the 120lb mark.
Sail area in this pic is 7.2sq m (78 sq ft) but I think like the Goat it would be sailed reefed some of the time.

The dagger board was a way of getting a rowing seat but still allowing enough room for a second person as well as allowing the crew to cram forward in light winds. It was the easiest part .. I drew in the centrecase and the rowing seat quickly as it seemed obvious even though I hadn't imagined it a couple of minutes before.

MIK

I wonder aloud if a higher aspect rig in a pointy nosed boat might just intensify the 'pig rooting' problem that plagues the PDRs when running downwind (seeing as how it is using the same spars as a duck)? Without the broad shoulders of the square front transom to hold up the nose, will it tend to cut under and broach with the pointy stem?

Rick.

Howdy Rick,

The thing that holds up the nose of the PDR at speed is the stern rocker - because it is so curved it gets pulled down by hydrodynamic forces. I do use a little bit of that effect in the SOG by keeping some curvature in the rocker at the back end. Not much, just a little otherwise it will be speed restricting like the PDRacer.

The "pig rooting" of the PDR only has an effect because that long bottom edge of the bow transom pulls the bow in really hard when it touches the water. Not enough to put the foredeck under like a scow moth but certainly enough to change the trim.

So while there is a lot of conversation about the sail forces pushing the bow under in the PDR it is only noticeable because of the hullshape. That the boat doesn't do anything stupid in terms of steering when it happens is because of the balance volumes fore and aft and the symmetrical waterlines fore and aft (a box is as symmetrical as you can get!)


The SOG with that very fine waterline forward (for a flat bottomed boat) won't be tripped up at all. If the stem hits the water there will be almost no affect on any hurtling progress.

Just like the goat with 3 or 4 people aboard trims down by the stem, but it still goes just fine.

Good question though

MIK

Originally Posted by Boatmik

Great point about the intermediate sitting position when coming off the gunwale. Will think through and reply to everyone when i get a bit more time later in the day.

MIK

Leave it as it is, add a beanbag as standard equipment?

Ian

Hi Mick

The beam seems to be spot on.

What about a smidgin more sail area? Maybe something like 85sq ft? Go for grunt

Also, with the skipper in place do you think the decks will drain to the cockpit? It's hard to tell.

Also, are the foils the same as for OZ PDR?

Very very nice, MIK. He's a real Son of a...gun? Goat? If we build one will we have to learn to refer to it as a him instead of a her?

A question about the GIS/SOG rudders. The angle of the transom puts the bottom of the rudder out in front of the transom. Does that give you the same effect as a balanced rudder shaped to have some portion ahead of the gudgeons?

If this is to be the offspring of a goat, it would be a kid. Kid Island Skiff or KIS ( I like that - a little play on 'Keep it Simple'!)

Originally Posted by woodeneye

What about a smidgin more sail area? Maybe something like 85sq ft? Go for grunt

SOG is going to be very light, very easily driven and will plane early. So there is a good argument that she will need very little sail area to go fast. Some builders will be tyro sailors others two handed skilled crews, so it would be nice to offer three sail sizes which all fit the same spars. Say 85, 75 and 65 sq ft.

As sail of 75 sq ft can easily add 10 sq ft simply by adding roach to the leach. About 4" roach with two short battens would do it.

So, a cruiser sail, a cruiser-racer sail and a racer sail all on the same spars. This meets the multi use talked about early on in the SOG thread. The sails themselves can be made very reasonably.

Brian