Thread: GIS X or Raid Special

Originally Posted by IanHowick

Hi Clint, when I first saw your GIS Yawl concept, I thought the way to go (rather than putting a new mast step in front of bulkhead one) was to increase the length by say 20%, while keeping everything in proportion. With the same sail, the centre of effort will be forward of where it was, which gives the opportunity to put your mizzen on to bring it back into balance. Would make a nice 18.5ft yawl that could be cruised, possibly set up so two could sleep on board.
Ian

Ian, that would have meant being locked into a yawl configuration. I liked the idea of preserving the Goat in its standard setting and having the ability to switch between yawl and lug only configs.

You can't just stretch the GIS without some repercussions either. The boat is too well designed! Actually, the way it is designed/built prevents someone from just spacing out stations and making a stretched version without having access to the 3D computer model. Well, it can be done but it is trickier than building a boat upside down over molds and frames that can be spaced apart at different spacings to make a shorter or longer boat. I've done it a few times (always with designer's blessing) and I recently said no to someone who wanted a 17' Whitehall at 15'.

I still think a 17 1/2-18' version would be great, especially for use with 3 people and more capacity for 4.

Originally Posted by robhosailor

Yes, I can see your objections, but an extreme Brynhild was used by her famous designer and builder (with his friend) for extended cruising (with cooking at sea between the squalls!!!) from Great Britain across an English Chanel (La Manche) and down French North Coast to the Breton... Than more is a function of skipper and his crew skills.

On a rainy day, when it's blowing, it would be nice to not have 15 C (59f) deg. water (in summer!) coming over the gunwale and into your shoulder for several hours as you travel from one island to another. It might persuade others to come too! Some chines, a forward deck, a splash guard, maybe a little more beam, a few inches at most... would improve the seaworthiness of the Goat considerably.

Originally Posted by callsign222

On a rainy day, when it's blowing, it would be nice to not have 15 C (59f) deg. water (in summer!) coming over the gunwale and into your shoulder for several hours as you travel from one island to another. It might persuade others to come too! Some chines, a forward deck, a splash guard, maybe a little more beam, a few inches at most... would improve the seaworthiness of the Goat considerably.

I think you could achieve most of what you want with the boat you have. Make a PVC foredeck, with an inflatable splash guard around the rear edge to keep the green water out. Bungee cord to hold it over the gunwale lip.

Add some beam with a couple of say 100mm x 200mm x 5000mm strips of closed cell foam going all the way around the outside of the gunwale, like an Inflatable Rescue Boat. Lots of extra buoyancy, extra beam when you are just about to go over. Might look ugly (or not?). Would also knock down spray coming off the chine and help it rise over any big green waves coming your way.

Put a piece of 100mm thick closed cell foam on each side of the centre board running all the way from under the middle seat forward to bulkhead two, cut to the exact shape of the floor. Hold it down with a big buoyancy bag that goes under the middle seat before being inflated hard. Something else holding it down at the front end.

More soon, with some more pictures.

Ian

Good thoughts, Ian, and I have thought of some of that, like the decking, but the GIS is still missing sleep aboard accommodations on or near the floor, and most importantly, I need a reason to build another boat! Anyway, it would be nice to look shipshape rather than a hodgepodge.

Fast and light, cheap and easy, sleep aboard and keep the water out.


EDIT and by shipshape I mean originally part of the design.

Originally Posted by callsign222

Anyway, it would be nice to look shipshape rather than a hodgepodge.

There's a pretty good pedigree to making "hodgepodge" alterations to boats to make them more seaworthy!





Ian

Haha!

True, except I haven't been stuck on a frozen continent for the past two years!

A Kiwi designer Jim Young produced a number of lightweight, hard chine, ply and water ballasted boats some fair while ago now. I have been unable to find pics, drawings etc but I did come across this New Zealand history of light weight yacht design written by designer Gary Baigent and thought it makes for interesting reading while one mulls over what is the perfect boat. OK it is mainly about keel boat development never the less the origins are distinctly dinghy.

http://www.coolmobility.com.au/Yacht/LightBrigade.pdf

Cheers

I often think this trend was really crystallised by the Hartley TS16.

MIK

The Hartley really was at the forefront of the stitch and glue renaissance for the trailer sailors. Easily built and light weight, it's easy to see why they became popular. Most of them weren't built with epoxy though (resorcinol), which is a shame because not many of those older ones have survived. The later epoxy glued ones have of course faired much better.

For now, I'm quite taken with Scruffie's 20' Secret. She's a real looker and moves nicely.

[ame=http://www.youtube.com/watch?v=0j9ZCLnkZ-8&feature=fvw]YouTube - Whisper the Secret going to windward[/ame]

She definitely a looker, but too much standing and running rigging for me on a 20 footer.
Oh the expense!

I think Small Craft Advisor has a write up on her a few months ago, Bruce, if you want to take a gander.

Originally Posted by callsign222

She definitely a looker, but too much standing and running rigging for me on a 20 footer.
Oh the expense!

I think Small Craft Advisor has a write up on her a few months ago, Bruce, if you want to take a gander.

I'll check it out, but may already have seen it. Edit: yes, in the #61 Jan/Feb 2010 Issue !

Yes, plenty of rigging. That's why I'd like to see MIK have a go at a fast sea kindly trailer-sailor one day

Originally Posted by Boatmik

Two perspectives on this ... (Bigger boat with Multi chine)

Construction - no probs.

First is that a chine panel increases serious pounding and you can't do anything about it. There is a kind of assumption that the boat will sail level and the vee of the bow will cut the waves. It is a very mistaken assumption. That's why sharpies are so well known for being dry and smooth sailing in rough water - apart from the usual big slam - more common in big sharpies than little ones because you can't control the boat heel.

Many modern racing yachts have gone to a much more square shape in cross section - now that they only have to worry about the speed of the hull rather than following a particular rule that shapes the hull.

I suspect that a lot of the hull failures in 70s and 80s lightweight yachts was because of falling down on flat flared topsides or bow sections.

Hi Mik, if I understand you correctly, you are saying that the shape of the bow section of the GIS ( \_/ ) (in combination with the other features which make it work) is more seaworthy/handles the rough stuff from all directions better than all the variety of multi chine/lapstrake/compound curved sections that other designers use. (Most of which end up as a V forward, moving to a more graduated chine or curve further back with various degrees of fineness, fullness and flare as you go back).

If this is so, it's worth saying it louder. Everyone seems to be assuming that by going to a more complicated shape/construction direction, gains in 'seaworthiness' will result.

Maybe the Goat is about as good as it is possible to be at this sort of stuff within the constraints of size and openness.

If so, that's great news, maybe I can cross 'something bigger' off the list, if I need a deck on the GIS I'll just follow the Worsley/Shackleton plan substituting PVC and bungee cord for canvas sailcloth and nails, and add more buoyancy bags and a sea anchor if I'm doing any more serious cruising in the future.

Ian

When you look at some very modern boats like Russell Coutt's RC44, you realise how very modern the GIS shape is. Yes, the RC44 is a keel boat, but nevertheless the similarities are interesting. In the promo video on the RC44 site, you will see snippets of the hull shape. The best one is at about 1:54 into the video as the boat breaches.

The RC44 - RC44's Official Website - Class Association

I think there are limitations to the slab sided hull. They throw water harder and more vertical. Ian's mega-gunwale could help this, definitely, as could side decks.

A rounded bilge would be more complicated and heavier with another designer, but if this goes anywhere, it would be a "design challenge", not a "design easy-peasey", and Mik is the man that could make a Super-Goat (light, cheap, easy to build) for rougher water and with sleep aboard capabilities.

The 44 is nice and all but a couple of things about these boats:

When we're in the Goat and we have 4' seas, those seas are a quarter of our hull length. Almost a third if they are 5'. If they're steep and close, boy-oh-boy, hang on to your hats! The 44 would have to be in 11-14.5' seas in comparison. Guess what? Them boys ain't going to go racing in 14' foot seas outside their swanky modern U.A.E. marina. Race cancelled, cocktails and tail instead. Last weekend in Portland harbor I was in steep 2-3' seas, and due to their configurations and our direction, we were taking water in over the bow in legitimate waves, not spray. Without Al to bail, I would've been kind of sunk... almost literally.

Not to mention that the 44 chine is rounded and not a hard edge, which, I think, does make a difference, in terms of catching and tripping-- there would be more skidding, but who knows if I know what I'm talking about now. I'm definitely not a yacht designer.

There are definite similarities between the 44 hull shape and the GIS hull shape, and this is very cool, but this is another conversation entirely. If we are talking about a more unsupported multi-day cruiser dinghy with the ability to sleep aboard, we should be maybe looking at other comparable hull forms that would allow such a thing. Just my opinion, and I hope you all are enjoying the back and forth.