I am curious how well they work. I single a H-18. I have managed to figure out how to get it righted but if it ever went turtle I'd be on a long slow ride to Canada.

Why?,

Stand on the aft corner that is the most downwind, and the mast should come up to windward. A boat that is turtled can usually be righted again, unless the mast is stuck in the mud. I've had to remove my PFD, and swim down a mast, and pull it out of a muddy bottom putting my feet agianst that same muddy bottom for leverage! Kinda scary. However, a mast float will prevent this kinda thing, check out those guys at Delray Beach, with all the mast floats, milk jugs, etc.

I fully agree with Todd. The mast-head float prevents turtling from happening in the first place.

Robert

As you all probably know by now, I am strongly in favor of all beach cats having some sort of masthead flotation, and it is probably especially important for cruisers (non-racers) who tend to do a lot of sailing when there may not be other boats around. However, (and I think I have mentioned this before, too), there is one thing you should be aware of if you use a Hobie bob. I discovered this with our Hobie Waves -- the bob floats the tip of the mast so well that once the boat capsizes, it tends to go skating downwind faster than if the mast were digging into the water. So in the event of capsize, make sure somebody holds onto the boat, or it can quickly get away from you.
Of course, any boat can easily get away from you after it capsizes, so holding onto the boat or something attached to the boat is always the primary consideration. It's just that the bob helps the boat get away a little faster.

Here's a photo of my Prindle 18 fitted with a Baby Bob float. I haven't gotten it wet yet, so I don't know how well it works. Maybe we'll test it out in a couple weeks down in Key Largo. We mainly sail in a shallow lake, so our main concern was keeping the mast and sails out of the mud.

Jack Hoying
Fort Loramie, Ohio
Prindle 18 #1645
http://www.bright.net/~jmhoying/sailing/prindle.htm

I've been thinking of ways to deal with this. This is not a cure but on boats that have spin.halyards, if needed, you could tie your throw-able floatation cushion to the haylard and pull the cushion "down" to help float the mast.

Mike

Here's a product that was advertised in a 1980s Hobie Hotline. Does anyone remember seeing one in action?

Jack Hoying
Fort Loramie, Ohio
Prindle 18 #1645
http://www.bright.net/~jmhoying/sailing/prindle.htm

Would a discus shaped mast head float act as a "canard" and improve the performance of the mainsail?

GARY

Gary, you look different somehow.
Or maybe I should say, "Grandma, your teeth are so BIG!"

Anyway, I looked up the definition of "canard," and I'm not sure what you mean in the context of a masthead float.

I have one installed on my TheMightyHobie18 and it works great. I glassed mine in though, because the rivets cracked the mast slightly when I was squeezing them. I've also heard of them braking off when they hit the water if you're going fast enough.

Canard is duck in French (I think). I don't think the humane society would look kindly on this practice, but it would probably work. You'd have to train the duck quite a bit first . . .
Can anyone explain "modulus of elasticity"?

We have Hobie Bob's on our fleet of Hunter 140's at Sail Sand Point, www.sailsandpoint.org. It is a great addition for safety, and a real time saver when righting the boats. As part of the US SAILING training format, all classes are required to turn over the boats, then right them.

Caleb Tarleton, Sail Sand Point

I'm sure when the duck hits the water in a capsize, it would be screaming, "Aflack!"

Basically it's a measurement of how elastic a given material is. It's a constant for certain materials. Soft stretchy materials (like aluminum compared to steel) tend to have a high MOE. Hard brittle materials tend to have a low MOE. The different aluminum alloys have widely varying MOEs too.

That was tongue in cheek from another thread, but thanks. I'm just trying to work my way up to pooh-bah, plus it's Friday afternoon.
The more I think of the duck idea, the more I like it. It could swim the mast into position for righting, or, better yet, PREVENT capsize or pitchpole by flying upwind! Of course, it would only be a matter of time before some hotshot had a great blue heron up there (maybe Wouter can calculate the necessary wingspan to prevent a pitchpole).
Happy Friday everyone.

Al, your duck is on the verge of infringing upon my idea of an articulating masthead airfoil which would give lift to the top of the mast and help prevent capsize.

Well Mary, you're still safe. Someone already patented the duck.

yeah well...poo-bah isn't all it's cracked up to be.

Jake,

You got that the wrong way round, Aluminium has a lower modulus of elasticity (70GPa)(often called Youngs modulus), and steel has a higher modulus of elasticity (200 GPa).

When you see equations for stiffness the Modulus of Elasticity is often represented by the letter E.

It is basicly a measure of how far a material will stretch under a given load (stiffness). A mast made from a lower modulus of elasticity material would be less stiff.

My Materials Science Professor would be ashamed

Whoops, I should have said "winglet" rather than "canard." I was refering to the winglets used at the tips of wings to reduce drag that is induced by a wing tip vortex.
"grin"
Triangular Mast Head Float?

But I guess that the location of the masthead bobber is too far from the leech of a square top sail to be used as a winglet.

GARY

I considered to buy a hobie bob, for about US140, but I reconsidered and bought one like this:


Just tie it to the sail, it goes up with the sail. The handles are pretty useful for tying

That looks like a Hobie "Bucky".

That's kind of what I thought you meant. Somebody just recently was telling me that Suicide sailors at one time were using endplates on the tops of their masts to reduce vortex drag at the top of the sail (or something like that). But it did not seem to do anything to improve performance, so they stopped using them.

The key to not turtling, though, is to seal the mast. Back in the day (like 6 years ago), I had a Hobie 16 that had met a power line in a storm. The line burnt a hole in the mast, maybe a 1.5 inches in diameter. Everytime the boat would flip, we'd have to get on the righting line immediately, or the boat would turtle in no time because the mast would fill up with water. I sold the boat shortly after, so no longer my problem. Anyway, I have an I-20, and the mast is sealed, and it takes it awhile to turtle. I can also solo-right the boat. I have a hobie-bob sitting around, but I'm never gonna use it...it just looks so amateur. I understand if you are a beginner that you need the peace of mind it provides, but once you've learned to right the boat even if turtled, then you've got it.

You have to realize that not everyone sails in 30' deep water. Driving you mast and sails into the bottom is a little hard on equipment. You are correct that a sealed mast is important, but for some of us that sail on shallow waters, a mast float is good insurance. Probably not a "must have" but I'm glad I have it.

Jack - proud to be "so amateur" looking
Fort Loramie, Ohio
P18 with Prindle Bob

Saying that using a bob looks "amateur" is like saying that bicycle riders who use helmets look amateur, even though the opposite is true.

A masthead float is a very important safety feature, and it is too bad everybody doesn't use them.

Even if you don't care about your own safety, you should use a masthead float if you ever take children out on your beach cat.

I thought I was so clever until I saw the pics posted in this thread with the CO2 tank. For the RTI race that was blown away last fall I stuffed two surplus airline PFD's into a bag. Fresh CO2 cartridges are in both PFD's. In the event of a pitchpole they will be inflated and hoisted on a dedicated halyard to the top of the mast. If I can keep the mast up (foam inside the mast), I MAY have a chance to recover from the feared pitchpole of my little trimaran but it will also require the use of a drogue (longer story for a later thread). I hope I never have to use it and with the price of CO2 cartridges, I haven't tested it, yet.

The good thing is that I have two extra PFD's on board to use for whatever or whenever they may be needed to be pressed into service.

I am here reminded that the Rave trimarans came without their masts being sealed, allowing rather discomforting pitchpoling. I personally rescued several of them at an important regatta. Even more disconcerting was the cavalier attitude of some owners toward mast sealing beforehand, as they stated that it was neither important nor necessary. I say it was and is.
There is so much stuff hanging off a Rave, why would it need a drogue?

I had a friend of mine that got stuck for a couple of hours turtled on a Viper 21 (21' sport monohull) off Hilton Head. He had to wait until a powerboat would help them pull the boat back on it's side. By then the keel-stepped mast had warbled a big hole in the top of the deck. A little later while cranking up the keel in preparation for putting it on the trailer, the eye pulled out of the top of the keel and it went straight to the bottom.

We later talked about how he might have had some luck by hoisting a couple of life vests or the throwables he had on board up the spinnaker halyard...hindsight is 20/20.

With the kind of beam on those Raves, do the masts have a chance of keeping the boat from going turtle?

Raves go over frontwards-- from flying out of the water at speed if altitude is poorly controlled, then coming down nose first. Result is a rapid, acute dive, as the inverted T-foils hit first and present a negative angle of attack while still going fast. The center hull fills immediately, stern is straight up.

OK....but do they stay there (whether it be on it's nose or on it's side) or do they turtle naturally?

Mary,
I would not compare a Hobie Bob to a bicycle helmet, it is more comparable to bicycle training wheels.
Like training wheels, it simplifies a potentially hazardous situation, while diminishing performance.
A Bob makes it more difficult to step a mast, causes greater pitching motion and makes a boat more prone to flipping.
A bicycle helmet has minimal effect on bike or rider performance.

Sam,
I wasn't comparing a bob to a bicycle helmet. It was just to illustrate that in both cases some non-users think of users as wimps. I don't think it is good to discourage people from using safety features by saying it makes them look like amateurs.

If you had seen as many boats turtling, many instantaneously, as I have over the past 16 years, maybe you would feel differently -- especially, as I said, if you are taking children or grandchildren out on your boat.

Sam and Jake, I am planning on putting a mast float on my H17. My reasoning? I don't want to have to watch a crew drown as the boat turtles, and they are trapped in lines or wires. I don't know how this happens, but have read about it on the old forum. I would've thought it happenning once would make everyone put floats on. I had one on my old 17 and wasn't bothered by the extra weight. It certainly eased righting on that boat. I have only turtled boats twice, both times were on a 16. I don't know if I could've gotten her back on her side solo, and wouldn't want to chance it on my 17.

Hey,

Don't drag me into this - I have nothing against the Hobie Bob...it's just that his brother 'Bill' up there looks kind of funny.

Usually the first thing I do when we capsize is to make sure neither of us is under the sails and mast, then check to make sure nobody sustained any injuries, and then try to keep the boat from going turtle. So far, the F18 has prooven very resistant to turtling even without a Bob or Bill.

Here are my throughts on the mast head float. I don't think they are for all boats and sailing conditions. Spin boats seem to pitch pole more than turn over on there side (or at least I do)and I think the mast float would put a lot of stress on the mast when fliping. Sometimes you want to turtle the boat. In a Worrell leg a few years ago we were in a bad storm 50 to 60 mph winds with hail and turned the boat over while tacking to get closer to shore. We sat on the hull waiting for the worst to blow over and the boat just righted itself throwing us off and fliping over on its other side. We turtled the boat after that to keep from drifting so fast and waiting for the worst to blow over. I have turtled several different kinds of boats and don't think it is a big deal (unless you are in shallow water) to right the boat even with my wife and we have to add weight to the boat.

I agree with Brian, that´s a good reason to put a mast float on any kind of boat, not just cats. Years ago, my father turtled a LaserII and found himself underwater unable to move, because the tiller was inside his lifevest. Fortunately he was calm enough to unmount the tiller, because his crew was not able to help him.

What a silly statement to say that having a Bob on your mast looks amateur. It's a safety device!!

I'm sure there are still people out there that think wearing personal flotation devices look amateur.

I'd say if you feel "amateur" because of a Bob you're probably a moron anyway and should stick to land. Did the guy who said this also say his mast met power lines in a storm?????!!!!!!

I rest my case.

I just wanted to clear up what a winglet does. It simply makes the wing more efficient. It does this by forcing the air to flow over the end of the wing as it does in the middle of the wing, straight back. Without the winglets (and the same hold true for our sails) the air near the tip spills off toward the end instead of straight back. On our cats we lose at the top and the bottom.

I think a float that was airfoil shaped could work on square top sails. I don't think it would need to provide lift. Thats the last place you want to create drag.

There is nothing wrong with a Hobie Bob for anyone that feels it might help. I've recommended the Hobie Bob to many people.

I also believe that it is not neccessary for people with plenty of experience and are very familiar with righting a cat.

Mike Hill
www.stlouiscats.com

It would be easy to design a self-inflating mast float that's just a CO2 cartdridge and airbag that sit up top just for an emergency. (minimal windage and weight) It could be activated by a pressure switch that has a time delay, or by a tiny line that activates the mast top device.
Go for it!

Mike,

It looks like you have successfully understood my comment/question about a discuss or triangular shaped bobber that would be relatively flat. I see two problems, besides the obvious problem of building a thin and wide float that would withstand the impact force of a violent pitch pole roll.

1) Winglets are usually located near the leech, rather than the luff.

2) A agree with David L. in that they are not for everyone. I for one, will stick with a mast that can be intentionally buried for survival at sea in heavy wind.

To take of #1, I would consider a teardrop shape that would span the entire chord of the square top sail.

To take care of #2: If I decide to add buoyancy up there, I'll go with the smallest, cheapest West Marine inflatable vest. It is an easy project. That vest is contained in its own waist pack that can easily be riveted to the mast and a pull string lead down to the dolphin striker.

But honestly, I keep my mast sealed enough to endure a turtle experience. And if I have to stay turtled for an extended period of time, I won't count on being able to right the boat again. Why? Because I wont' count on my mast not having a very small leak that would eventually fill it up if left turtled for hours. After that, I don't think that an inflated horseshoe vest would be enough buoyancy to lift the mast and sails to the surface.

GARY

Jack,

That piece of work looks just as "amateur" as everything else that I've seen you build!

I'll bet you have the only, or at least the first "Prindle-Bob."

GARY

When surviving a storm at sea, wouldn't it be better to keep the boat upright, drop the sails, and use a drogue or sea anchor?

Not always. First of all, The only drouge I carry is a righting line and a gear bag. Second: Sometimes it is unsafe or impossible to upright a capsized cat. Third: A mainsail extending 31' beneath the surface is a pretty darn good drogue!

Fist of all, I am not a moron. A tornado touched down nearby and dragged my Hobie 16 along with its mooring into the channel, and then to the back of a cove and that is when it found the power lines. Don't make ASSumptions. I maybe I was wrong to say the Hobie bob looks amateur, but what do I know, right? I'm just saying that if I showed up to a regatta with a hobie bob on my I-20, I'd get laughed off the water.
Trey
I-20 314

Fair enough. My appologies.

SOME CLARIFICATION

First, most Rave skippers have never pitchpoled. They've only read about it from the few that have. Second, it's about a spectacular as a capsize but presents an unenviable position of not being able to recover with a single-handed skipper.

["Raves go over frontwards-- from flying out of the water at speed if altitude is poorly controlled, then coming down nose first. Result is a rapid, acute dive, as the inverted T-foils hit first and present a negative angle of attack while still going fast."]
A Rave will fly out of the water but usually only once or twice per owner when he is learning how to tension the flaps. When a Rave flies out of the water, it PANCAKES with a big splash because it does not gain enough altitude to arc into a dive. The pitchpole happens when, like a cat, the bows dig and that happens after an unexpected big gust or simply bad trim.

["The center hull fills immediately, stern is straight up."]
The central hull does not fill unless waves are breaking into the boat. In fact, when Dave towed my boat to shore I had been out there for five hours and more than a little hypothermic by the end of the day. There was no water in the hull because after a pitchpole the boat floats with the beam about a foot above the water's surface and the first opening to the hull is two feet above the beam.
Calm water would have to jump up three feet to get into the crew's seat hole. If the central hull had filled, Dave's boat would not have been able to tow me to shore.

I tried hanging off the stern while Dave's boat with a line tied to the stern tried to pull the Rave back to vertical. The problem is that pulling a pitchpoled Rave simply pulls the boat through the water. So, we gave up and I sat out there for five hours while the rest of the regatta was run. A drogue forward of the beam, opposite the pulling line attached to the stern, would have provided the resistance needed pull the boat back to vertical.

The Rave is seventeen feet wide with three T-foils five feet deep and a short rig. With a platform like that, there has not been one report of a Rave capsize.

Dean, would it be possible to flood one of the amas in an attempt to right it?

Gary
From what I've heard some "BOBS" break off upon hitting the water. Poor attachment? I think a small cross section like a foil would offer little resistiance entering the water. Like anything no matter how well you make it someone can and will break it.

For now when needed I'll run something boyant up...er down my mast.

Too Late!

auto inflator device for the mast:

Try this AntiCapsize Device

And this for the instruction details:
Instructions


Price listed on the website is $158 Eur including the VAT (16%)...so it's cheaper than the life jackets and the shape is better suited, volume is> higher. Mechanism is exactly the same (a salt pellet dissolves when submersed to release the trigger spring on the CO2 cylinder).

Further clarification...the air that flows off the tip of the wing (or sail) does so from the high pressure (windward) side to the low pressure (leeward) side, thereby reducing the pressure difference between the sides...and therefore the lift force...which is exactly the opposite of what you want to achieve...
This effect is known as "Tip Loss". It also occurs on our rudder/center/dagger boards.

Mike, I could have gone on and on and on like some do making the simple not. Point is the wing is more efficient with a winglet.

K.I.S.S.

Hi, Mike,

Sorry I'm late with these responses but I'm actually having to work for my money this week.

Flooding an ama might help in a capsize, a la Corsair righting, but I haven't heard of a Rave capsizing. The pitchpole is the booger that is to be avoided with a Rave and flooding an ama would pull the boat to that side and I think the resultant attitude would be a pitchpole with a terrible list. It might invite turtling. I dunno.

I have floatation in the bow, the mast, in the amas. One does the best to avoid it but, like I said, I haven't heard of that many pitchpoles since the boat came out in 1999. It's not a bad habit; just something to be aware of. No multihull is for normal people. If we were normal we'd all be fishing for bass in a boat from Wal-Mart.

Whoa! I have to have one of those anit-capsize things. Thanks for the 'site, Mike.

My CO2 life jackets were only $5 each at the surplus store but the cartridges are a bit pricey. If I had to use somehting like this it would be easier to hit a button than to run something up a halyard hoping that it didn't become hung up on something on the way up.

16% VAT. Ouch. I will have to start saving some pennies for a purchase in order to avoid the MasterCard guard at my house.

P.S.: I bought a slightly used mainsail from Steve Calvert last week. They do a good job down there. I can't wait until the snow melts here in Orlando.

I don't believe you pay VAT if the item is for export from Europe. Reason I stated the price to be lower than lifejackets...I bought a manual inflator type for crewing aboard Afterburner (52 ft beachcat!). It cost ~$180, though it does has a safety harness built in.

Mike.

I dug out a picture that I have of a MacGreggor 36 with just the sort of mast head float that I was suggesting. I also found where Tom House had posted a sketch drawing of it.
Picture and drawing

GARY

Mary and I had a Mac36 that had the wing float at the top and did very well with it.
We won most of the races we were in. Don't think it slowed us down any.

Great part was that the boat came with a self-righting system. After the boat was on its side (unable to turtle because of the masthead float), you pulled out the huge waterbag stored on deck, used the jib sheet and spin pole, attached the spin pole to a ring installed under the tramp on the hull and the other end to the jib sheet attached to the bag.
Fill the bag with water and winch the boat upright.

At least that was what the instructions said, although we never had to use it.

Rick

Jack, are you sure that is an Hobie Bob? It looks like a Prindle Pete.

I read somewhere that a raindrop is the most perfect aerodynamic shape. And then in an article about raindrops, I found the attached, computer-generated drawing of a virtual raindrop.

It will look very familiar to anybody who has a Hobie bob.

So, IF a raindrop is indeed the most perfect aerodynamic shape, even if a Hobie bob doesn't provide any lift, at least it seems that it would present the least possible amount of drag.

if the volume of the float has to be aerodymnamic only, maybe so.
However it could serve a second purpose (lift shape) It would seem best to make it a flexible wedge of foam integrated into the top of the sail to give it thickness, like padded sails were. Then it would contribute no additional drag.

I think that David's idea is near perfect in design. Implimentation may be tricky, but if you could make the sail take a perfect shape on either tack, this would be a favorable way to carry an anti-turtle float.

Perhaps inflated battens as on a traction (kite-boarding) kite?

GARY

I don't get that. If you make the top of your sail fat and symmetrical, wouldn't you lose some drive out of it and also cause some drag?

I'm not sure I understand the "wedge" thing and which-a-way it is pointed or placed in relation to the sail.

I am just interested in all this stuff because I would like to see something invented that would be practical for people to use for safety reasons and at the same time be acceptable to the serious racers -- the bob snobs.

Not symetrical. Asymetic as a windwurfer sail or a traction kite. It would have to be able to invert for each tack, providing a convex cuve on the lee side and a concave shape on the windward side.

GARY

Okay, I thought you were talking about a wedge-shaped wedge, but I guess you're not. Some sails are made with a pocket at the top for a piece of flat flotation. Is that what you are talking about? Or something else?

That is it. The padded sail was not for flotation but to give thickness, like the semi- soft sails on faSter ultralights etc. This is a preferable sail profile, but of course has its complications, but when combined with the need for flotation, could justify itself and lead to a technological leap through the back door, so to speak. Wing sails are the future. Spin's are not. When the lift of slotted rigs is realized (very high lift to area ratios off the wind, because the wind can be "bent" around the slats a lot, and drag is not an issue), there will be no need for spin's.
I gues the comparison is that airplanes land at comparitively low speed with all kinds of slots, flaps and slats deployed, because drag does not matter.(you are trying to put the brakes on, and burn up altitude, so you have energy to spare) You need lift at low speed. You could achieve it with a new type parachute foil too perhaps.
A sailboat meets this technology from the other end by not caring about drag when off the wind because the wind (drag)is about in the same direction as he wants to go. He too could (and does) use a parachute/kite type device to this end. They are a pain to deploy, but apparently easier for boats to use than planes....

Would a sail be more efficient if it were flat on the windward side instead of concave? In other words, more like an airplane wing? (For the sake of the question, assume that the boat will only sail on one tack.)

This has been tried on the 12 meter AC boats. Stars and Stripes tried a two sided, hollow sail. The idea was to be able to control the shape of the sail by varying the tension on either panel. I don't believe they raced with it.

Sort of. A low speed wing needs some thickness but actualy still needs to be concave on the "underside". This varies with the lift/drag required as well. (windward or leeward again)Some thickness is always required, and better than none.
If Hobie Bob was symetrical and stretched for the length of the square head, this would be an improvment, because it would also help out the end plate effect (See other thread). However I dont think it would be that hard to make an articulated one. Say a alligator (kids toy) looking bunch of foam segments that radiused into each other with a batten looking thing spine. The fit need not be perfect (actually a gap is prefered) just so long as the flow can stay attached.
Reading back over: If you follow that, you get a prize..

Depends on what the prize is.