Thread: Solo "Expedition" Sailboat

Well should you use caution in asking about it.

Version 12 ... has just bitten the dust. Long live version 13.

I can't believe it ... I wanted to use the simplified deck edge construction of the PDR and I haven't left enough width to get the deck out of a ply sheet .. dumb, dumb, dumb.

It means that instead of just bringing the deck down on the gunwale that I will need a deck clamp too. Which means two extra pieces of 19 x 25 the length of the boat.

There might be a way though ... Let me meditate!!!

MIK, in one of the Goat threads you mention using ballast for singlehanded sailing and reducing the amount as confidence grows. I think there was a mention of Solo possibly using water ballast.

I guess the displacement of Solo will include the boat, the sailor and a fair allowance for expedition kit, food and water for drinking. So I was wondering, for day sailing this would leave the possibilty of putting water containers under the floor perhaps as ballast for windy day sailing or for newer sailors to build their confidence. Could be a really popular feature for builders.

Water ballast seems to work for the Swallow boats Bayraider and I have realised that a larger proportion of members of the UK Home Boat Builders Group are less experienced sailors than are very experienced sailors.

Here are a number of YouTube vdeos of Swallows tests with and without ballast.
[media]http://www.youtube.com/watch?v=cL6xmOGCCOo[/media]

http://www.swallowboats.co.uk/content/view/127/

We have had really windy summers now for the last two years. Racing again yesterday in 18 knots gusting 20 knots. Great racing, terrific fun but exhausting and so I was thinking that something to calm the boat down for longer distance sailing would be pretty good.

Brian

Ok ... share with you ....

Originally Posted by keyhavenpotter

There is something you could do to really help me though. I have planned to meet up with Chris, who is building Raid41 this winter for me, next weekend (Sept 6th and 7th) to go over ideas and plans etc. He lives at the other end of the country to me, so not easy to meet up. There is a Home Boatbuilders Meet in the Cotswolds where we plan to sort and finalise build plans for Raid41.

Would it be possible to let us have anything - obviously marked up not for building with or cutting any materials. Anything showing ply layout would help a lot to create a basic budget. With your experience of other designs, your estimate of the costs to build hull, foils and spars would help us loads. I am paying for all materials, Chris wants to build the boat. Then I am rigging her and also I really want to sew the sails over the winter so any programmes for lug sail design or panel latouts later on would be helpfull.

I guess I am saying anything we can just have in front of us to talk over the build would be great. We both really want to create this super little raid boat with a really tight budget to show every body at the Beale Show next year just what can be achieved.

All the best, Brian

I think to say you have my support is a huge understatement!!!

Thanks for understanding that final information is some way away yet.

I do have some panel layouts already even though I don't have the final panel shapes. And I can give you list of sizes for most of the timber from various sources. You might have to guess the lengths (trick .. they are either 16 or less than 4ft long!)

Mast, centreboard and rudder box is all off the PDR. Mainsail is off Beth, mizzen is so simple it is a joke.

Structure is PDR mostly.

So priority for me this week is to cut and paste it all together for you.

OK

MIK

MIK,

It's great to hear that you are on the home stretch.

John H. Wright posted a great article at http://www.duckworksmagazine.com/08/howto/pdx/index.htm following his experience with his PDRacer in the Texas200:

John noted that a Texas 200 boat should have, at least, these following qualities:

• Rugged enough to survive wind and rough water for five days.
• The sail plan to allow for high wind and also have enough size for the possible light wind.
• Ample dry storage for supplies.
• Able to sail in shallow water but also sail close to the wind for the occasional beat into the wind.
• Adequate space for sleeping in the boat as an alternative to tent camping.
• Protection from mosquitoes and rain.
• Shade while sailing….and not.
• Self bailing or a large bucket for quick de watering and a sponge to keep it dry.
• Inherent floatation adequate for self rescuing in rough water.
• Easy (proven) way of getting “you” back in the boat.
• A working and proper pair of oars.
• A proper anchor with at least 50’ of (preferably) nylon rode (rope) attached securely to the boat.
• The last but not least important, a COMFORTABLE seat.

He summarizes this by noting that the above, is, a lot to ask of an 8’ foot boat.

What is not on the list is sufficient speed for safety, a limitation of an 8' foot boat that simply cannot be overcome. The Raid41 will pull all these pieces together in a boat that will allow you to avoid trouble and arrive in time to enjoy the cold beers.

Thanks for your continuing efforts.

EJK

Thanks MIK and thanks EJK for starting this thread!

Chris has just confirmed due to the logistics of obtaining marine plywood so far north (he lives at the end of the known world - though it is very nice there ) that we will be ordering ply a couple of days after our Cotswold meeting. I am getting excited.

EJK - have a look at the Lug Rig Heaven thread and my rigging pics show a neat system of using an adjustable stirrup to climb back on board. I think with that all the listed requirements are covered by Raid41.

Brian.

Originally Posted by keyhavenpotter

[back in May 2008]
Thanks MIK. Very nice. Very desirable. Very quick.
Inexperienced with spar making - could the spars be put through a thicknesser to square them, again with wedges to taper them, then a router to radius the edges. 100 times better than trying to make round spars if it would work.

Brian

G'day Brian
have just knocked up some spars for my poor beknighted Teal's new sail.
Dead easy - see MIK's free paddle plans for blow-by-blow instructions.
Shape square, mark & plane required taper/s.
Use spar gauge to mark accurately for 8-siding with hand plane.
Use spar gauge or Mk.1 eyeball to 16-side with hand-plane.
Round off with sand-paper.

The hardest bit (after getting motivated enough to make a start on them) was
ripping two clear lengths out of the knotty old rafter I used as stock. In the end
I had to scarf the yard from two shorter bits. That, & varnishing them - I have no
aptitude for painting whatsoever, (and regularly inform the wife of this !! )

Looking forward to getting my mitts on a set of SEB plans... (2009 project)

cheers
Alan J

Just keeping the thread near the top of the heap...
You will let us know when the plans are ready, won't you MIK ?
Have 'pox & filler. Just need plywood & time...
cheers
AJ

Yep, good to see this thread rise to the top again. I think you can add me to the list of buyers for the plans. Is the idea that you buy the Oz PD plans for construction details and then an additional drawing pack for the RAID41 panel shapes?

Chris

I think an experienced builder would not need the PDR plans at all ... it will be a lot more detailed than a set of panel shapes. But it won't be a whole Storer Plans step by step, follow every detail, type plan.

And Chris, the chap who is building the first boat (starting the 1st of November (gulp) does tend to do collect photos on the way through.

Brian ... can you put a link here to Chris' his website?

MIK

Glad to hear the Raid41 still has legs. I'm very hopeful that you will have plans released soon. I am really looking forward to a Spring launch (Winter comes way to early and stays way to late in Minnesota).

Erik

Besides the clear aesthetic benefit, what makes a daggerboard more desirable than leeboard(s) on a boat like this? Is there a performance advantage?

Just curious with the concerns about space early in the thread why leeboard(s) are not part of this.

Thanks - sorry for the (possibly) stupid question

On the contrary Dogfuel ... this is a truly GREAT question. I will do a comprehensive answer as to why in a little while.

My original reason is that I am pretty sure leeboards don't perform as well as centreboards by some margin unless set up to be a bit complicated in use.

The reason I can do a comprehensive answer is because the worldwide PDRacer fleet has been hugely experimental with rigs and foils ... and I have been a careful observer of this wonderful mayhem.

MIK, here is the link to the website

please everyone have a look through the different builds, (under pages),

Stangarra is a new Oughtred canoe
Scotch Mist a MacGregor Sailing canoe
Bumble of Lochdubh, a Humble Bee

and Candyfloss is a CLC Wood Duck just in build for a neighbour.

Chris will blog the whole build, warts and all, so will provide a terrific build resource for all of us.

http://strathkanchris.wordpress.com/

Brian

Originally Posted by dogfuel

Besides the clear aesthetic benefit, what makes a daggerboard more desirable than leeboard(s) on a boat like this? Is there a performance advantage?

Just curious with the concerns about space early in the thread why leeboard(s) are not part of this.

Thanks - sorry for the (possibly) stupid question

OK ... I will start with my reasoned prejudice and then move onto some interesting evidence from the PDRacer experimentation in the USA. Finally a positive approach to leeboards and this boat.

My Prejudiced Viewpoint about leeboards
First ... there have been a few experiments to make a leeboarded/bilgboarded raceboat in yacht sizings. Some of them have had significant budget including a couple of different attempts in the heyday of the IOR rule which penalised stability quite strongly ... so having a deep and heavy keel was not the preferred way for ANY boat.

So even against other lightly ballasted boats ... the highly optimised bilge board boat was not terribly successful despite having enough crew to pull up the windward board.

We now see a number of the canting keel yachts using leeboard/canards ... this is a bit of a special case as these boats are so powerful and so fast that they can generate a lot of lift from their canted leeboard/canard.

Not a normal leeboard and not a normal boat ... after all the bigger ones have engines to swing the main keel from side to side ... how many miles per gallon to Hobart boys?

ok ..

The second thing in the reasoned prejudice line is that in general one foil is much more efficient than two. There is always a loss at the tip - two keels ... then two lots of losses ... which is why catamarans will generally sail with one pulled up.

For one person ... this is too much work I think.

FOR EFFICIENCY ... ONE LEEBOARD NEEDS TO BE PULLED UP.

So the third thing ... the guy who has designed more leeboard boats than anyone else, Phil Bolger says "before anyone asks, yes they do have to be that big, and especially that wide and, yes, they do collect pot warp etc"

So factor in that both of them have to be almost the same size as the centreboard they are replacing. This can be moderated in boats that heel by canting the leeboards out at an angle so they are perpendicular when heeled ... but most small boats like this are better at very moderate amounts of heel.

AREA OF TWO LEEBOARDS WILL ALWAYS BE GREATER THAN A SINGLE CENTREBOARD FOR THE SAME EFFECT

The other thing is that surface piercing foils (leeboards on the outside of the hull or a rudder off the transom) are in theory and in measurement much less efficient than a foil that goes through the hull.

LEEBOARDS SHOULD BE INSIDE THE HULL RATHER THAN MOUNTED OUTSIDE

Fourth thing ... this is really argued prejudice on my part ... I don't have any solid evidence the flow of water around a chine has a tendency to become quite turbulent quite easily. Having a leeboard in this turbulent flow is going to cause more drag for the hull and less efficiency for the leeboard itself

REPEAT OF PREVIOUS POINT - a good argument for bringing a leeboard inside the hull. A number of the US PDRacers have done just this .. and a couple using OZ PDR plans have moved the centrecase over so it is under the inside edge of the deck about 7inches inside the hull side. If someone wants to do this on the RAID/EXPEDITION41 then they can try of course. I think it will be OK .. but not as good as the centreboard.

Puddleduck experiments with unbalancing
Interesting ... something from the puddleduck world.

One of the PDRACERS used a biplane rig (attached pic below) it was build by Dave Gray of Polysail fame. If you are after good polytarp for a PDRacer sail in the Americas .. he is the guy to contact.

The PDRacer rules allow a wide range of rig configurations ... there are everything from this biplane to a brigantine.

The most common rigs however have been sprit and lugs as well as a few sloops.

The biplane rig is quite a good performer upwind with careful sail trimming .... very effective downwind as in the pic below ... but cross wind is somewhat slow because of the blanketing.

The boat has two rigs and two leeboards.

Now when Dave reefs ... he simply leaves one of the masts and sails on the shore.

If he sails with one rig only and the leeboard on the same side of the boat then it sails very nicely.

But if he sails with the rig on one side and the leeboard on the other then it won't sail effectively at all. If he can get it going at all it has big weather helm on one tack and big lee helm on the other.

So ... if you design a boat with an offcentre mast and a leeboard .. take them over to the same side of the hull.

So why does this strange balance problem occur? One of the important things with the design of any boat is to do a drawing from the side of the hull/keel/centreoboard/leeboard (an elevation) working out the centre of the sail area and put that over the centre of the hull. With shallow, almost fore and aft symmetrical boats like the PDRacer and most dinghies you can almost ignore the hull and just use the centreboard position.

BUT this is very much a two dimensional solution. It works ok if the mast and the centreboard are on the same line as the system is symmetrical. But the actual situation is not 2D it is 3D.

That is, the force from the sail is not only lateral .. but slightly forward as well ( when going upwind) that is why the boat moves forward so it is a good thing. The centreboard, leeboard or keel deals with the sideforce which leaves the slight forward force as the only thing that is unbalanced so the boat moves forward.

This means that when the sail is full the centreboard or leeboard needs to be somewhere along the line of action of the sail.

When the sail and mast are on the centreline of the boat ... they have very little lateral separation so the centres line up fairly closely. This is true for a mast and leeboard that along a line parallel with the boat centreline.

BUT, this also means that if the leeboard is on the lee side it needs to be slightly forward ... or if the boat is wide .. a long way forward. And if it is on the windward side it needs to be an equal distance back.

This means a single leeboard boat will always be a bit out of balance on each tack. With the rudder producing drag as it resists the extra weather helm on one tack and the extra lee helm on the other.

It appears that if the mast is on the centreline and the leeboard is on the side of the boat (ie they have a 2ft lateral seperation) then the rudder can cope OK and the boat will be fine. But double it to 4ft and the rudder doesn't have enough oomph to cope adequately.

What some design books say about catamaran/multihull centreboards
NOW .. an interesting thing ... a number of design textbooks claim that multihulls with centreboards in the outer hulls have to have them quite a long way forward relative to the sail compared to a monohull because of the drag of the leeward hull tending to make the boat bear away.

Maybe ... but it is clear a secondary reason ... or maybe the primary reason is that the catamaran centreboard has to be forward to be positioned on the line of action of the sail centre.

Interesting how a little humble boat like the PDR can be quite informative in a very concrete way about some of the features of much more flash boats.

What Bolger says about asymmetry
Bolger ... who I regard as a truly brilliant designer does say that boats don't seem to mind asymmetry in mast and foil position. However the PDRacer experiments show that there are limits. I would suggest that Bolger tends to design relatively slender boats so the lateral offset is not too large and also when a boat has both leeboard and mast offset he takes them over to the same side. I think most designers would tend to do this fairly instinctively.

If you want a leeboard on the RAID41
But back to the Expedition/RAID41 ... when Brian said he would build the first one he said he would prefer a swinging centreboard. I suggested keeping it as a dagger so it won't ruin the cockpit for sleeping and the simplicity of building. I think he had his doubts but he went with the simplicity angle.

As far as leeboards go ... if someone wants to try them .... they are welcome to try but if the boat has shortcomings .. they will also know who to blame.

But guidelines would be .... think about keeping the leeboard/s inboard of the side of the boat just under the side deck edge. Incidentally the ketch/yawl rig will be more tolerant of the slight changes of balance from tack to tack compared to anything else.

Maybe that is another reason Bolger's offcentredness works ok.

Best wishes
Michael Storer