Large sharpie for the Adriatic

[rnlock]

You're right about that.

That eight to nine knots with an 8 hp sounds extremely "optimistic".
snip
What 28 foot yacht can reach about 25% over hull speed with an 8hp? Is a 28'er with an 8hp really going to motor about 20% faster than a 36 foot cruiser/racer with a 20hp diesel and a similar or lower displacement to length ratio?

I know that motoring speeds don't directly equate to sailing speed, but to reach that sort of figure the Parker 28 would have to be close to the fastest 28'er mono in the entire world in terms of hull drag. Faster than the carbon bulb-keeled sportsboats; faster than the Mini Transats. Why would the world's best racing designers be stupid enough to design slow boats?

snip

I'll bet a Folding Schooner could do eight or nine knots on 8 hp, if the prop was right. You'd have to cut off part of it to get down to 28 feet. Of course, that's not a similar displacement to length ratio, but it IS a sharpie. The original Folding Schooner kept up with a bunch of other much heavier schooners in the race it was built for. I imagine that with two or three really large windsurfer rigs instead of a gaff schooner rig would keep up with a whole bunch of other, far more expensive boats.

 

[sharpii2]

I think part of the confusion here is that fast, displacement sailboat hulls do not make the fastest displacement powerboat hulls, atleast for low power.

A sailboat gets its speed from (RM/Disp) -- drag. A non-planing powerboat gets its speed from (power/Disp.) -- drag.

The two are very similar but not the same. A lot of drag, particularly at high non-planing speeds, comes from wave making. A narrow boat makes less waves than a wider boat of the same length. This is why kayaks and destroyers are so narrow.

But a narrow sailboat doesn't work out so well when it comes to getting the highest speeds in the widest range of wind conditions.

The reason for this is its limited ability to carry sail. It isn't much of a problem to make a narrow sailboat go fast in windy conditions. Just put a small rig on it and enjoy the ride.

But when the wind drops to a gentle breeze, this small rig does not have what it takes to keep the boat moving. Now, it needs a bigger rig. This means a taller mast. And a taller mast comes with the square of its increased length ratio in top hamper, if the same technology is to be used (materials and stayed or unstayed). There are three ways to deal with this problem:
1.) Increase the ballast ratio,
2.) Increase the depth of the ballast, and
3.) Increase the Beam.

The first option soon becomes impractical as the increased ballast hogs more and more of the usable displacement.

The second option soon creates draft issues, as well as friction drag ones.

This leaves the third option, which works quite well, as long as it isn't taken to extremes.

The original sharpies came about before engines in fishing boats became practical (at around the turn of the 20th century).

These boats had to get to their fishing grounds, wind or no wind.
And often there was no wind.

Then, they had to be rowed. And a narrow boat usually rows better than a wide one--especially in a glassy swell.

As they got bigger, rowing became less practical, but the greater size allowed disproportionately larger rigs.

Smaller working sailboats, not intended to be rowed long distances, tended to be beamier. This allowed them to carry enough of a rig to handle light wind conditions.

Racing sailboats evolved from these wider work boats.

So, when under sail, a good, modern racing sailboat should be able to beat a good sharpie. But under the same amount of (engine) power, for the same WL length and displacement, it could easily be another story.

 

[CT249]

You're right about that.



I'll bet a Folding Schooner could do eight or nine knots on 8 hp, if the prop was right. You'd have to cut off part of it to get down to 28 feet. Of course, that's not a similar displacement to length ratio, but it IS a sharpie. The original Folding Schooner kept up with a bunch of other much heavier schooners in the race it was built for. I imagine that with two or three really large windsurfer rigs instead of a gaff schooner rig would keep up with a whole bunch of other, far more expensive boats.

The folding schooner that raced in Australia was surprisingly slow in all but a fresh reach. It was rated about as fast as a typical ‘60s 20-22 foot trailerable cruiser like a Catalina 22; far slower than 1930s racers or any other open boat. The Norwalk Island Sharpies don’t rate very fast.

Great boats, but not fast ones.

 

[CT249]

I think part of the confusion here is that fast, displacement sailboat hulls do not make the fastest displacement powerboat hulls, atleast for low power.

A sailboat gets its speed from (RM/Disp) -- drag. A non-planing powerboat gets its speed from (power/Disp.) -- drag.

The two are very similar but not the same. A lot of drag, particularly at high non-planing speeds, comes from wave making. A narrow boat makes less waves than a wider boat of the same length. This is why kayaks and destroyers are so narrow.

But a narrow sailboat doesn't work out so well when it comes to getting the highest speeds in the widest range of wind conditions.

The reason for this is its limited ability to carry sail. It isn't much of a problem to make a narrow sailboat go fast in windy conditions. Just put a small rig on it and enjoy the ride.

But when the wind drops to a gentle breeze, this small rig does not have what it takes to keep the boat moving. Now, it needs a bigger rig. This means a taller mast. And a taller mast comes with the square of its increased length ratio in top hamper, if the same technology is to be used (materials and stayed or unstayed). There are three ways to deal with this problem:
1.) Increase the ballast ratio,
2.) Increase the depth of the ballast, and
3.) Increase the Beam.

The first option soon becomes impractical as the increased ballast hogs more and more of the usable displacement.

The second option soon creates draft issues, as well as friction drag ones.

This leaves the third option, which works quite well, as long as it isn't taken to extremes.

The original sharpies came about before engines in fishing boats became practical (at around the turn of the 20th century).

These boats had to get to their fishing grounds, wind or no wind.
And often there was no wind.

Then, they had to be rowed. And a narrow boat usually rows better than a wide one--especially in a glassy swell.

As they got bigger, rowing became less practical, but the greater size allowed disproportionately larger rigs.

Smaller working sailboats, not intended to be rowed long distances, tended to be beamier. This allowed them to carry enough of a rig to handle light wind conditions.

Racing sailboats evolved from these wider work boats.

So, when under sail, a good, modern racing sailboat should be able to beat a good sharpie. But under the same amount of (engine) power, for the same WL length and displacement, it could easily be another story.

As noted, my boat isn’t significantly Beamer than an Egret. Other 28 footers I’ve sailed on are 8’2” overall beam, probably skinnier on the waterline and certainly as little as 2/3 the claimed weight of an Egret, and almost as fast as a Melges 24. You don’t get that sort of performance with a hull that has high drag at any speed- but it wouldn’t go as fast under power as this ad claims for the Egret.

 

[rnlock]

The folding schooner that raced in Australia was surprisingly slow in all but a fresh reach. It was rated about as fast as a typical ‘60s 20-22 foot trailerable cruiser like a Catalina 22; far slower than 1930s racers or any other open boat. The Norwalk Island Sharpies don’t rate very fast.

Great boats, but not fast ones.

I thought that boat was the Light Schooner (aka Scooner), not the Folding Schooner. Was there a Folding Schooner, too? In any case, the Folding Schooner is actually built a little lighter. For instance, the bottom in the plans is 1/4", rather than the doubled 1/4" in the Light Schooner. The Light Schooner has floor gratings, decks, etc. that the Folding Schooner doesn't. Not only that, but it's 7 1/2 feet longer with the same width.

Point of sail, or even speed under sail on some of those points, isn't especially relevant when we're talking about speed under power. Plus it's not fair to compare a simple, low rig with one that's much taller. Both the Light Schooner and the Folding Schooner had much lower displacements than the Catalina 22. The Catalina 22's "basic weight" is given as 2250 pounds. You can't tow that behind a 1900 cc Opel, but you can tow a Folding Schooner with that car. Also, Bolger was able to fold and unfold it by himself, so my guess is each half weighed no more than 150 lbs. Let's say the total is 450 lbs with rig and all. Add 175 lbs for our intrepid captain, another 175 lbs for the crew, and 50 lbs of odds and ends. What does an 8hp outboard weigh? 100 lbs? Total is now 950, but we'll round it off at 1,000. I suspect the waterline is around 28 feet. That gives a displacement to length ratio of something like an absurdly low 20*!! (Unless I screwed up the numbers.) Plus, the waterline length may increase if it starts to form a wake. And hull speed, theoretically, for a 28 foot waterline is 7 knots, isn't it? So 8 knots would hardly be exceeding hull speed. Now the question is whether it planes or not while going 8 or 9 knots.

Info on Scooner and Folding Schooner from "30 Odd Boats" and "The Folding Schooner", both by Phil Bolger.
Light schooner design and behaviour http://www.ace.net.au/schooner/lsinfo.htm

*In imperial units. A D/L under 90 is considered "ultralight", at least according to Sail magazine. I think I've seen similar numbers elsewhere. Comparing Design Ratios https://www.sailmagazine.com/boats/comparing-design-ratios

 

[tane]

heretic alternative, vastly superior to any sharpie in any aspect:
Birvidic 700 https://www.fr-lucas.com/birvidic-700-1701

 

[rnlock]

Vastly superior except for things like cost, skills required to build, dependence on the availability of specialized hardware, skills required to maintain, etc. There are sharpies you can build just with stuff from the local lumberyard. I'm not saying those are the best sharpies, just that they exist.

I have no doubt the Birvidic 700 is a wonderful boat for some people.

 

[sharpii2]

As noted, my boat isn’t significantly Beamer than an Egret. Other 28 footers I’ve sailed on are 8’2” overall beam, probably skinnier on the waterline and certainly as little as 2/3 the claimed weight of an Egret, and almost as fast as a Melges 24. You don’t get that sort of performance with a hull that has high drag at any speed- but it wouldn’t go as fast under power as this ad claims for the Egret.

IMHO, it's not just the actual water surface waterline that matters but those immediately above them. So, a hull that has straight, flaired sections is going to be different than one more rounded sections, even if the waterline Beam, the waterline length, and the displacement are the same. This is why sailing dories evolved to having round hull sections instead of straight, flaired ones. They did this to get the buoyancy to shift further to the leeward side when the boat heeled.

But working dories kept their straight, flaired sides. Why? So they would row easier.

To put enough sail area on a boat to make it sail faster, certain changes in the hull shape are needed. It must have higher initial stability, but also greater forward pitch resistance. Then there is the keel. A deeper, shorter keel is definitely better for sailing, for ballast placement and hydrodynamic reasons, but it is harder to drag through the water than a low aspect ratio one, if the low aspect ratio one is shallower, even if it has more surface area.

I'm not saying the ad is true. I'm only saying that, just because a boat sails faster than another, with the same size and weight, does not mean it will always power faster, or even power as fast.

 

[tane]

Vastly superior except for things like cost, skills required to build, dependence on the availability of specialized hardware, skills required to maintain, etc. There are sharpies you can build just with stuff from the local lumberyard. I'm not saying those are the best sharpies, just that they exist.

I have no doubt the Birvidic 700 is a wonderful boat for some people.

cost should not differ much, if materials of same quality are used.
building skills: note that files for precutting by CNC router are included in the plans (= zero skills required) & that practically no piece of timber has to be beveled, all joints are by epoxy fillet & tape.
Sailing ability & resale value will be vastly superior to any sharpie, with the same draft keel up.
not to speak of seaworthyness...

 

[tane]

& there is a Birvidic 28 in the pipeline, if a bigger boat is needed.

 

[rnlock]

cost should not differ much, if materials of same quality are used.
building skills: note that files for precutting by CNC router are included in the plans (= zero skills required) & that practically no piece of timber has to be beveled, all joints are by epoxy fillet & tape.
Sailing ability & resale value will be vastly superior to any sharpie, with the same draft keel up.
not to speak of seaworthyness...

Actually, the cost will differ a great deal. There's no problem using lumberyard materials for instant boats and the like, which are very cheap. If zero skills are applied, the glue joints will all fall apart, epoxy won't set right, the paint will peel, and so on. Then there's all that hardware, plus the aluminum spars, wire, wire fittings, etc., as opposed to free standing wood masts. And a whole lot more parts. The sails on the Birvidic will cost more,. I'm not saying the Birvidic isn't superior in many ways, at least for some purposes, but that's far from being superior in every aspect. For instance, if I really wanted a sharpie, I could afford to build one. Say, a Birdwatcher Birdwatcher – 23′-6″ x 5′-7″ – H.H. Payson & Company https://www.instantboats.com/product/birdwatcher-23-6-x-5-7/ or a Laguna with a cabin added Laguna Plans PDF https://duckworks.com/laguna-plans/
Actually, in the past, a Bolger Brick was far more suitable for my needs than a Birvidic. Not everyone's needs, desires, abilities, opportunities, and budgets are the same, and that means what's superior for you may be greatly inferior for me. For instance, I could never have put the Birvidic on my car's roof, even without the Nymph inside it.
Brick https://www.duckworksmagazine.com/03/r/excerpts/bwaom/01/brick.htm
Duckworks Magazine https://www.duckworksmagazine.com/07/projects/nymph/index.htm
My friend's kids wouldn't have liked a Birvidic any more than they liked his sailboat of about the same size, but they loved my Brick. "All aspects" just isn't an objective thing.
You have to ignore most of the universe to say something is superior in all aspects, especially when you don't qualify the statement.

Nevertheless, if the Birvidic is right for you, that's great. It's definitely not right for me. Or Igor, I'd guess.

 

[tane]

Actually, the cost will differ a great deal. There's no problem using lumberyard materials for instant boats and the like, which are very cheap. If zero skills are applied, the glue joints will all fall apart, epoxy won't set right, the paint will peel, and so on. Then there's all that hardware, plus the aluminum spars, wire, wire fittings, etc., as opposed to free standing wood masts. And a whole lot more parts. The sails on the Birvidic will cost more,. I'm not saying the Birvidic isn't superior in many ways, at least for some purposes, but that's far from being superior in every aspect. For instance, if I really wanted a sharpie, I could afford to build one. Say, a Birdwatcher Birdwatcher – 23′-6″ x 5′-7″ – H.H. Payson & Company https://www.instantboats.com/product/birdwatcher-23-6-x-5-7/ or a Laguna with a cabin added Laguna Plans PDF https://duckworks.com/laguna-plans/
Actually, in the past, a Bolger Brick was far more suitable for my needs than a Birvidic. Not everyone's needs, desires, abilities, opportunities, and budgets are the same, and that means what's superior for you may be greatly inferior for me. For instance, I could never have put the Birvidic on my car's roof, even without the Nymph inside it.
Brick https://www.duckworksmagazine.com/03/r/excerpts/bwaom/01/brick.htm
Duckworks Magazine https://www.duckworksmagazine.com/07/projects/nymph/index.htm
My friend's kids wouldn't have liked a Birvidic any more than they liked his sailboat of about the same size, but they loved my Brick. "All aspects" just isn't an objective thing.
You have to ignore most of the universe to say something is superior in all aspects, especially when you don't qualify the statement.

Nevertheless, if the Birvidic is right for you, that's great. It's definitely not right for me. Or Igor, I'd guess.

Actually the Birvidic was/is not right for me, it just looked right for what I assume(d) was the intended purpose of the boat: safe (category C), quick, fun-to-sail, basic accomodation, self righting, unsinkable, variable draft with extremely shallow keel-up setting, trailable (of course NOT on a car's roof), easily amateur-built of simple materials (ply/Epoxy), retro look, ..
with "no-skills" of course I meant "no sophisticated skills": somebody unable to execute a fillet+tape joint will not be able to build a satifactory dory type either, no?
The Birvidic has 2 sails just as some dories, I guess a wooden mast could be made if the expense of an aluminium one is too much (will it be cheaper, if made from good materials?)
I myself fell into the trap "really-simple-looking-boat-is-so-much-cheaper-to-build-than a-"yachtie"-one" more than 45 years ago. The boat I chose to build was only slightly less work than a more "sophisticated" design & was cheaper only because I used second grade materials & outfitted to a very low standard (inferior grade ply & lumber, hardly any electrics, cheapest Far Eastern sails, no lifelines, no plumbing,...)
(btw: building (as a complete greenhorn!) & 7 years rtw-ing her was an unforgettable adventure though! But not BECAUSE the boat was a good one, but DESPITE it' faults. We could have had just as much fun with a better, slightly more sophisticated design)

 

[rnlock]

Just substituting a wooden mast in a design meant for an aluminum one is probably a bad idea.

 

[tane]

Just substituting a wooden mast in a design meant for an aluminum one is probably a bad idea.

I didn't mean "any old electricity pole", of course.
(I have no personal interest in the Birvidic, btw, & "retro"aesthetics do not appeal to me at all. I just find the hull very elegant & the building systen really intriguing)

 

[rnlock]

I didn't mean "any old electricity pole", of course.
(I have no personal interest in the Birvidic, btw, & "retro"aesthetics do not appeal to me at all. I just find the hull very elegant & the building systen really intriguing)

I didn't either, but wood is not aluminum.