New US1M pictures

Rcsailing.net General Discussion
1

Long overdue.
Some of you may remember that I posted some information on plug construction, and then slacked off on keeping it up to date with hull construction and the likes, well here is some of the finished “product.”

http://www.ourwalden.net/rcsailing/2004us1m.html

The only parts not home built are the electronics, the mast, and the sails (not pictured). I normally use Black Magick sails, futaba electronics and various masts.

I hope to have on water sailing pictures next week!

-Todd

2

Todd

Dang looks good.

Interesting stand for the boat. Now you have to tell how you made it

Jeff
Alberta

3

Hey Todd,

Interesting design.

The profile looks alot like a Cobra only it is considerably narrower and appears to have the rocker further aft. What is the designed displacement? Does it stick with the modern trend of lower displacements?

With the reduced beam and prismatic, I assume she heels quite a bit in a blow. Can you gauge how she heels relative to other designs that you have raced against?

what diameter mast are you using? It looks pretty large? Did you consider a smaller diameter mast with shrouds? If so, why did you elect to go with the bigger mast and shroudless?

Finally, are you running with more than 2 channels? Do you have a backstay or jib sheet or twitcher?

Anyway, A fine job. I guess I had better get cracking on mine now, eh?

  • Will

Will Gorgen

4

looks real good todd
you did a great job on the hull. i cant wait to see it on the water. good luck with it
cougar
long live the cup and cris dickson

5

Will,

I think in pictures, all boats look relatively the same, put in person, if you put this side by side with a cobra, you wouldnt even put them in the same family.

Anyhow, As for the rocker, its maximum point is dead nuts centered on the boat. The center bouyancy however is not.

The boat is designed with a displacement of 5.5 lbs ideally but could probably be sailed well as light as 5.25, and I am currently sailing it as heavy as 6.1 lbs. I want to sail it at about 5.6 personally, but have been cursed with an ailment(http://www.ourwalden.net/limes) that has left me without the use of my hands, and there for not capable of trimming down my bulb which currently weighs 4.1 lbs or so. But, she does sail well even at that 6.0 + lbs of weight.

She does heel a couple of degrees more than the boats I race against, but she was designed to do so. There is actually an optimal heel angle built into the hull design. Most of the boats I race against have been trying to go light, on boats that were designed to be heavy, thought wide, with the reduced ballast, in a blow, they lift too much of the hull out of the water with negative consequences. . . Hard to explain without two boats on water next to each other.

Masts. . . the mast that is in for the pictures is my super stiff C-rig mast. Something that would survive armageddon. It is just below the limit of maximum mast diameter. My A and B rig are noteably narrower . . . but could still be narrower with shrouds. I elected to NOT go shroudless for two reasons.

  1. With a boat this narrow, shrouds are like tits on a bull (useless). If you do the trig inorder to effect the mast at all, the loads have to be VERY high. This means I would have to add weight and stiffness to the hull near the chainplates. By allowing all the forces to go directly to the keel and no where else, I can save on weight overall to tolerate the larger, stiffer, heavier mast.
  2. Ease of use. Not as much to hook up to go sail. Quicker rig changes, less tuning, Keep it simple!
  3. Auto depowering. . . Sailed some skiffs with rigs that were designed to flex off in a blow and spill air out of the top of the sail where it was hurting you the most. Kinda liked that, thought that with a narrow boat, it might yield some good results.
  4. and finally, in most of the locations I sail in, the fastest race is the cleanest race. Shrouds just add one more thing that can snag on another boat. By keeping everything as clean as possible, when that random person hits you, you are less likely to get stuck together and capable of sailing away rather than sitting there and having to take a DNF or DFL.

I knew I said 2 reasons, and then gave four. . . oops, I am sure there are more. I personally dont like spreaders and shrouds and diamonds. There are masts out there that are stiff enough to deal with the loads on their own without increasing diameter and weight too much, such as the sections from grahm bantock. Do this if you can. Take a smaller diameter, lighter mast that is rigged with spreaders and shrouds . . . weigh it compared to the 10mm od bantock section. . . I bet it is within a fraction of an ounce after adding all the shrouds and spreaders. Now take each section, and swing it through the air like a golf club, but at about the speed wind goes over your mast (10mph+/-) . . . which has more wind resistance? I know how my answer turned out.

Channels . . . 2. Keep it simple. Less things to think about in the boat, the more I can think about out of the boat. The fraction of speed I may gain with either of those other devices is offset the first time I screw something else up while thinking about how they are set, or forget to re adjust the trim. Also, I dont think carrying around the additional weight warrants their use. . . just my oppinion, but you have to remember that I am a relative newbie. . . that being said, if I were to add a third channel, it would be to adjust the jib slot relative to the main. I think there is more speed gain there then anywhere else.

Off to sail, and hopefully get some on water pictures!

-Todd

6

Todd

all I can say is "Holy [:-censored] "

I sure hope your hands heal up real fast and with no problems.

I always wondered why a x girlfriend wore latex gloves when she was preparing items for the bar. Granted one reason was for public saftey but I do remember her saying that the limes and lemons caused her hands to develop a rash.

Oh and the boat is sweet

Jeff
Alberta

7

The hands are getting there. . . slowly but surely.

As for on water pictures. No race today, but here are a few taken today in some really variable conditions. Scroll down to the bottom of the same link. Lots of big pictures, may take a minute or so to load.

http://www.ourwalden.net/rcsailing/2004us1m.html

-Todd

8

Yikes! Those margarita blisters look nasty and painful! It reminds me of a really bad case of sunburn I got about 15 years ago while windsurfing in Aruba. My boardshirts would ride up on my thighs while I was waterstarting and would rub off all the sunblock leaving my legs exposed. By the end of the week, my legs were beyond red. There were large patches of blisters. Over the next week or two I loaded the skin up with aloe and wrapped it with gauze to keep it medicated. Eventually a patch of skin about 8" wide by 12" long came off of each leg (in one large piece each). I still have discoloration on that portion of my leg… Ever since then, I wear a pair of bike shorts under by board shorts to protect my legs… I hope everything heals up for you!

I think you are right about it being difficult to see the subtleties of hull shape in pictures. I could tell that the boat was quite narrow.

I was keenly interested in your mast. I am running a shroudless rig on my canting mast boat and everyone I have talked to has suggested that I need diamond stays. I have a 10mm dia pulltruded carbon spar that will have an 7.7mm tube insereted inside of it over the lower 10 inches or so (the canting mechanism uses the smaller tube which then serves as the mast base. The larger tube slides over it allowing me to switch rigs even with the canting base being permanently mounted to the boat). I’ve been hesitating putting the diamonds on (I have bought the spreaders, tangs and turnbuckles to build it, but don’t want to put it on until I am sure I need it).

I think I will leave the diamonds off until I have had a chance to put the sails onto the rig and see how it bends under wind pressure. They are easy to add later.

I know what you mean about entanglements…

Thanks for taking the time to share some of your engineering thoughts. I hope it was not too painful to do all that typing with your hands in such rough shape.

  • Will

Will Gorgen