Its coming...BobAbout 2

25 years after penning my original Footy design I have her worthy successor almost ready for the world to see.(2 months of silence on this forum has sped up development)
Longer, lighter and faster than ever before:)
The journey is almost complete ,all that has been learned as been summed up in a simple design that anyone can build for a few bucks.
The mk2 mac rig is performing better than the original designs that have been widely copied.
I couldn’t be more happy with what has been achieved.
watch this thread for details of the new design which will be available to all…

Brett

Thanks Brett, I look forward to seeing it, and probably building one. Is it designed in the same idiom of recent American cars, retaining some of the Bob About’s charm but in a new, sleek form. Paul

Exactly right paul!
The similarity of Bobabout is there for all to see,but in an easier to build and faster hull shape.
I guess it is the first available plan for a “long footy”

Hey Brett,

I look forward to the refined Bob-A-Bout. I have built three and a half (started one earlier this week) from the plans I received from you several years ago. Thanks for all your work!

You’re such a tease…be dropping the kimono soon, I hope…anxious to see the new rig!

Bill

My prototypes are very rough from hacks and experiments on hull shape ,keel area and placement etc etc.So I am at the stage of building my 4th version(final) of the boat.
I will post some pics soon enough.
The design process began by writing a basic Footy VPP based on my towing experiments a few years ago and also factoring in observations of the approx 30 different designs I have built and sailed.I also have tried to read between the lines of all reports on Footy racing that have been published and match them to my own data.This has been a lengthy and involved exercise to say the least.
So little is known about these small boats and there is still much to learn but this latest design is a pretty good stab I believe on the parameters for a successful boat in this class(how the rules stand now anyway) One caveat though is that I have restricted my thinking only to ballasted mono hulls,the mental excursion required to think about all other alternatives is just to great.
Construction has to be simple and great effort has gone into making the hull shape both hydro dynamically correct and simple…I think I have achieved this with a the shape created,This I believe is my greatest asset as a yacht designer…finding the balance between simplicity and performance or $$ vs speed.In the case of this boat though $$$ and more expensive construction will make very small gains.

As mentioned the Rig has had a refinement made also. The much copied “mac rig” does really appear to be the way forward,I think it could be made to work on larger yachts to and I intend to experiment in the future(perhaps an RG 65 or RM)
On 2nd thoughts I may not publish the MK2 rig,my store of tricks gets smaller by the day and I may need to keep something up my sleeve if this class ever gets to having important events.The MK1 versions I have seen on this forum are sometimes not correctly built and it is very frustrating to see that…knowing that your boats could sail much better just by modifying the rig geometry,the MK2 version will most likely cloud these issues further.More education is still required for many to understand the way the rigs work and should be built.
This past season has been very busy for me…I have competed in 3 National championships in full size craft finishing in the top 3 each time(Boats from 7.8m to dinghies of 3.5m)
Have also been deeply involved with Optimist coaching as well has this Footy project.
I am now lucky to have two young competent r/c skippers to test my models whilst I watch and learn,this has been a tremendous help to developing the models,we have sailed boats side by side for hours on end studying the differences.
Anyway,I hope the class gets a lift from this new boat just as the it did from the plans of the original “BobAbout” in 2000

Teaser specs:)
LOA of the new hull is 335mm and max beam is 94mm

ahhh a corner-to-corner hull…

I can’t think of many reasons to have a short boat under this rule…so heres a couple of pics of one of the protos…and one of the development team in solitary training

Brett,

It looks good. An interesting design, it should be easy to build. What was the motivation for the reversed transom? Weight saving? A better fit in the box? Looks? Or are you using the vertical diagonal, with the stern down? It also looks like you moved the hull a little off the diagonal to get a wider stern (assuming you used the horizontal diagonal).

One of my friends recently built a boat completely on the horizontal diagonal, with pointed bow and stern, but it had a totally flat bottom (no rocker), and it appeared to be slow. I am guessing that it was caused by the relatively large exit angle (30 degrees) on the sides. Your design has avoided that problem.

We are anxiously awaiting the details. Spring is here, the ice is gone, and our local racing has already commenced.

Hi Walt.
Yes the boat fits diagonally and down and slightly offset in the box with out getting silly about it.
The raked transom is one spin off from this…doesn’t look to bad and saves some weight.
By going down on an angle within the box you also get to have some bow overhang which also helps a little.This is my longest boat to date at 335mm.

This boat came about from my experience with what I believe to be my best boat yet…“Comet”.
Bob2 is really a hard chine version of “Comet” with slightly higher displacement.
“Comet” is a very complex shape and would be differcult to reproduce,so Bob 2 is the answer to that.Performance differences between Comet and Bob are minimal ,almost undetectable.
You can see pics of comet elsewhere on this forum.

Brett,

I have recently mailed Bill H asking about his interpretation of Footy measurement of the “B” rig with particular reference to whether or not the hull has to be propped up such that the deck is level with the box top.

Is your interpretation that, with a “B” rig in place and close hauled, the bulb can sit on the bottom of the box as long as the top of the rig is no more than 305 mm above the top. The implication of this is that, when floating on its lines, the mast top could be more than the magic 305 mm above the deck.

I ask this because I have recently heared of a boat being declared illegal because the deck was not at box top level and with Liverpool on the horizon I don’t want to be caught out myself.

Cheers,

firstfooty

Hi Firstfooty,

I don’t believe that the deck has to be level with the measurement box during measurement.
Indeed the boat can fit into the box anyway you see fit.
When you have set up the boat in the box to your liking then the height of the “B” rig can be checked…no more than 305mm from the top of the box.
BUT…you must be able to rotate your booms from running on starboard tack to running on port tack(ie right out both sides) without any part of the rig touching the box. This last part is to satisfy the “In racing trim” part of the rule.
That is my belief anyway…I hold no office in any regard concerning the Footy class rules anymore…I merely helped write them.

This is exactly how it was explained to me by Bill Hagerup. This means that yes, the total rig height might be higher than 305mm, but the working portion would still be 305 or less since in order for the booms to clear the box when in trim they’ll still need to be above the box. You can, however get a sail to be all of the 305mm by having the gap between the boom (yard arm?) and the deck be in the box.

I’ve consulted with my Tech Committee to make sure we all agreed. Our unanimous conclusion is that the boat can sit in any position in the box, and the 305mm measurement of the storm rig is taken from the top edge of the box. Brett’s interpretation is correct and reflects what we intended from the beginning. His caution about the need for full motion of the rig was included in my response to Trevor as well.

Bill H

Here is “Brujo” positioned diagonally and on an angle in the measurement box. The “cutwater”, or raised deck is to help keep the low bow from burying downwind and the position in the box also allows the bow to overhang, putting more reserve buoyancy out in front. The tradeoff for gaining a much longer waterline and smoother transitions in the hull lines is that the keel depth is about an inch and a half shorter, reducing potential righting moment. You don’t get something for nothing as they say.

“Brujo” has undergone some modifications since I took this photo. Her placement in the box isn’t quite as extreme so the waterline length is now only 13 inches. Sloped transoms are a means of getting the stern of the boat into the corner of the box so most of the boats that feature diagonal placement will have them.

Bill & Brett,

Thanks you both for your very quick replies - I’ll change my rig tomorrow.

The significant requirement seems to be that the “B” rig has to be able to rotate through its full range of movement without any part of the fixed hull being above the top of the box.

So does this mean that Niel’s “Brujo”, as in his photograph, would probably fail the box test as well ? It seems unlikely that any full movement could be obtained at the angle shown, and not much room for raising it up either.

As a newcomer to radio sailing the Footy’s is the only set of rules I’ve come across and I couldn’t see anywhere where the the full range of movement requirement came in. Is it, perhaps, implicit in the definition of Rule B1 " in racing trim " ? Since the Footy class is aimed, in part, at the beginner, perhaps a later version of the rules could be a bit more explicit on this point along with the Rule Interpretation No.1 about rudders ?

Thanks again.

Cheers,

Firstfooty

what’s old is new again … check the pics under the post “rig shadows” midway down the page … they show a potential rigging solution for Brujo

http://www.rcsailing.net/forum1/showthread.php?t=3853&highlight=blue+sky&page=3

First Footy,
I did forget to add something.
if any part of the rig or sail are within the box that is fine…all parts however must be able to be rotated without fouling the box,either inside of it or outside.

Firstfooty - “Brujo” has a ridged deck or cutwater that runs parallel just below the top rim of the box. The swing rig’s pivot point is at the apex of the cutwater. The mainboom has a bend in it that allows the rig to clear the edges of the box. My sail shape is not as radical as TMark’s because the rig is carried near the top of the box.

TMark - Yes, the Blue Sky Project inspired me to try angled placement with my new design but as a further development I also placed her diagonally in the box at the same time.

Brujo hasn’t been tested yet because I am still working out some construction issues. As a general policy though I don’t like to release details of a new design until it has proven to have potential. I have shared this pre-release view because this thread about BobAbout2 mentions the same placement concept incorporated in Brujo. Since I discussed the design brief with Brett some months ago I am not surprised to see that BobAbout2 makes use this sort of placement in the box. I haven’t seen this placement mentioned anywhere before this thread. I think that a more comprehensive explanation of the advantages, and therefore the reasons for building Brujo would be helpful to all.

As most of the readers of this forum are probably aware, a lot of us who are design oriented are now making boats that are placed in the box on a diagonal. The reason is to gain extra waterline length. Now corner to corner placement pushes boats to adopt pointy ends to maximize the possible length. Brett’s “Comet”, loosely based on Roger Stollery’s “Roar Edge” M class boat, is one example of a Footy with a pointy stern. The most waterline length you can gain through diagonal placement is 13 3/16th inches (335 mm). But double-enders may not be the archetypal hull form for Footies, unless they are extremely narrow the hull has very curved lines. The only way to have that maximum waterline and retain a moderate transom is to angle the diagonally placed hull. I chose to angle my stern down, although the bow could have been angled down. Bow down has many disadvantages, both functionally and aesthetically with a reverse pitch of the bow.

Stern down has many upsides. Longer waterline plus regular transom but also provides for having an overhanging bow, putting reserve bouyancy ahead of the boat and allowing more deck width up forward without resorting to a blunt bow (vis-a-vie Dump Truck).

Practically, to get a regular transom into the box corner with this placement it needs to be raked to order move the transom’s top edge at deckline as far forward (and therefore away from the box sides) as possible. One change to Brujo that I’ve made since the photo was taken is to meld the transom into the deck as one smooth, continuous surface.

Brujo sports a fairly low bow which brings the hull up higher in the box. The low bow is a risk that I hope will be offset by the overhang (which increases her reserve bouyancy as mentioned before). I have also incorporated the cutwater deck. In the event that this boat should nose under the sharp deck ridge will prevent the water from piling up on the deck and should help her to recover more quickly. The cutwater deck is then a backup solution to diving which I also use to elevate the rig pivot to the top of the box. The trade-off is that Brujo sacrifices keel depth for increased waterline length and the smoother hull shape of a longer boat. This may become a problem with righting moment, but there is a school of thought in Footydom that holds that our maximum keel fins are part of the diving problem downwind and the high aspect stalls too easily. I guess that I will find out if all this give and take will mean anything.

In conclusion, Brujo is a concept boat that is on its way to sea trials soon. All the things that have gone into my thinking in developing this design are somewhat contingent on each other. If this boat is a success or a failure the hard part will be distinguishing what works well and what doesn’t. But then thats what makes this class interesting.

Firstfooty - “Brujo” has a ridged deck or cutwater that runs parallel just below the top rim of the box. The swing rig’s pivot point is at the apex of the cutwater. The mainboom has a bend in it that allows the rig to clear the edges of the box. My sail shape is not as radical as TMark’s because the rig is carried near the top of the box.

TMark - Yes, the Blue Sky Project inspired me to try angled placement with my new design but as a further development I also placed her diagonally in the box at the same time.

Brujo hasn’t been tested yet because I am still working out some construction issues. As a general policy though I don’t like to release details of a new design until it has proven to have potential. I have shared this pre-release view because this thread about BobAbout2 mentions the same placement concept incorporated in Brujo. Since I discussed the design brief with Brett some months ago I am not surprised to see that BobAbout2 makes use this sort of placement in the box. I haven’t seen this placement mentioned anywhere before this thread, so I think that a more comprehensive explanation of the advantages, and therefore the reasons for building Brujo would be helpful to all.

As most of the readers of this forum are probably aware, a lot of us who are design oriented are now making boats that are placed in the box on a diagonal. The reason is to gain extra waterline length. Now corner to corner placement pushes boats to adopt pointy ends to maximize the possible length. Brett’s “Comet”, loosely based on Roger Stollery’s “Roar Edge” M class boat, is one example of a Footy with a pointy stern. The most waterline length you can gain through diagonal placement is 13 3/16th inches (335 mm). But double-enders may not be the archetypal hull form for Footies, unless they are extremely narrow the hull has very curved lines. The only way to have that maximum waterline and retain a moderate transom is to angle the diagonally placed hull. I chose to angle my stern down, although the bow could have been angled down. Bow down has many disadvantages, both functionally and aesthetically with a reverse pitch of the bow.

Stern down has many upsides. Longer waterline plus regular transom but also provides for having an overhanging bow, putting reserve bouyancy ahead of the boat and allowing more deck width up forward without resorting to a blunt bow (vis-a-vie Dump Truck).

Practically, to get a regular transom into the box corner with this placement it needs to be raked to order move the transom’s top edge at deckline as far forward (and therefore away from the box sides) as possible. One change to Brujo that I’ve made since the photo was taken is to meld the transom into the deck as one smooth, continuous surface.

Brujo sports a fairly low bow which brings the hull up higher in the box. The low bow is a risk that I hope will be offset by the overhang (which increases her reserve bouyancy as mentioned before). I have also incorporated the cutwater deck. In the event that this boat should nose under the sharp deck ridge will prevent the water from piling up on the deck and should help her to recover more quickly. The cutwater deck is then a backup solution to diving which I also use to elevate the rig pivot to the top of the box. The trade-off is that Brujo sacrifices keel depth for increased waterline length and the smoother hull shape of a longer boat. This may become a problem with righting moment, but there is a school of thought in Footydom that holds that our maximum keel fins are part of the diving problem downwind and the high aspect stalls too easily. I guess that I will find out if all this give and take will mean anything.

In conclusion, Brujo is a concept boat that is on its way to sea trials soon. All the things that have gone into my thinking in developing this design are somewhat contingent on each other. If this boat is a success or a failure the hard part will be distinguishing what works well and what doesn’t. But then thats what makes this class interesting.