Espritmodel.com Telemetry Radio
View Poll Results: If you are reading this thread are you an IOM owner
Yes 26 49.06%
No 27 50.94%
Voters: 53. You may not vote on this poll

Reply
Thread Tools
Old Dec 10, 2009, 05:37 AM
Registered User
larrykin's Avatar
Sydney, Australia
Joined May 2008
424 Posts
Quote:
Originally Posted by pchicken View Post
Hi Again,

Larry to have some experienced IOM skippers offer you information here may I suggest not conveying your first told thoughts of "IOM sailors are W.....s". It just may be that those you spoke with are in the minority
p
PChicken,
I was quoting non IOM skippers. That was before I had met any IOM guys. I have found the IOM people will in fact "talk your leg off" if you show an interest in their boats. Sometimes too much. For a newbie like me it can be information overload.
Shows how basic I am by asking about colours. I've just painted my boat yellow with a red bow (airbrushed), so I can see which way it's pointing .
Next week have to attack boat with a saw to fit new electrics . Oh what fun.
PChicken, are you in pommie land?

Larry.
larrykin is offline Find More Posts by larrykin
Reply With Quote
Sign up now
to remove ads between posts
Old Dec 10, 2009, 06:25 AM
Registered User
Joined Apr 2002
1,860 Posts
Quote:
Originally Posted by pchicken View Post
Robert
The call for 3 servos is unwarranted and just sounds like an excuse. The good well set up IOMs sail just fine in hands free mode.

p
My comment about the rules wasn't a call for 3 servos, its not an excuse. I have chosen not to race IOMs for a reason. I think that one rule is wrong. If Helicopters were restricted to fixed pitch heads I wouldn't bother with Helis, if on Fixed wing I had to choose between either Ailerons or Rudder I wouldn't bother with fixed wing. The discussion was that the MYA told me that rule was as it was to make the class available to all. This argument is pure non sense given the cost of the allowable bolt ons.

I my original post was to encourage discussion and to prompt people to think about their sailing rather than just accept what the club champion is doing/buying and often selling as the best for the sport.

Here is something to think about and an explanation why I think hulls are be forced to sail backwards; The Reynolds number of water for an IOM means that effectively we are sailing in Treacle. Water is about 1000 times thicker than Air so it is my argument that hull form and what goes on under the waterline that has the biggest effect on boat speed. That is why I dislike rudders so much, they are a brake.

How many fish swim backwards? (I can't think of one) Airfoil sections, name one section that flies trailing edge first. You can't! again for the same reason (Reynolds) both nature and science dictate that the blunt end, rather than the thin pointy end goes first; and so it should be with boats, blunt and bouyant bows with every effort directed at achieving laminar flow and bring the CP much further forward were it can help absorb the power from the exaggerated rigs whose best efforts are inevitably aimed at shoving the bow under water. Unfortunately all that effort become wasted as soon at the rudder is being used to control weather helm. Bubbling boiling water off a transom is a clear indication of turbulent flow, a sign that the brakes are on.

You fellas ought to get to bed, its getting late now
Robert May is offline Find More Posts by Robert May
Reply With Quote
Old Dec 10, 2009, 06:32 AM
Registered User
larrykin's Avatar
Sydney, Australia
Joined May 2008
424 Posts
Robert,
depends which country you're in. Here in Australia it's 11:30pm. Yes, bedtime.

LL
larrykin is offline Find More Posts by larrykin
Reply With Quote
Old Dec 10, 2009, 06:42 AM
Registered User
Joined Apr 2002
1,860 Posts
Thanks Larry, a perfect example of how you simply can not trim a boat effectively for all points of sail is shown in Picture 5, The text on picture 5 is correct for only one point of sailing; the Beat. On a dead Run that advice will increase weather helm. which will can only be corrected by... The Rudder. Who posted that comment earlier on about one of their boats being a dog downwind? There is a reason.
Robert May is offline Find More Posts by Robert May
Reply With Quote
Old Dec 10, 2009, 06:56 AM
Registered User
Siri's Avatar
Joined Oct 2008
91 Posts
Quote:
Originally Posted by larrykin View Post
Mike,
the Reggea or Reggae is the name. Only because young Chris on another post (Emo build) bought the plans. I love the fact he is now posting on how to make a mold for fibreglassing, never having built a boat that has sailed .

Thing with me is I enjoy building. I raced for the first time last week. Came last of course but that could have been.... list is too long. In 2 weeks I'll have a much better boat. But I can build a new USOM in 2 weeks. Wish there were more buyers. Yes that is me on ebay. Below is a YouTube of my first USOM sailing. Sold for $500. I now have 4 boats all of which are for sale. I need space to build more. The moulds (male) are for sale as well.

Larry

http://www.youtube.com/watch?v=RxyfeuK4suc
Larry,
are you posting to sell your boats?

Siri
Siri is offline Find More Posts by Siri
Reply With Quote
Old Dec 10, 2009, 06:56 AM
Registered User
Joined Apr 2002
1,860 Posts
Quote:
Originally Posted by larrykin View Post
Robert,
depends which country you're in. Here in Australia it's 11:30pm. Yes, bedtime.

LL

It was you guys in Oz I was thinking of, Goodnight! Now try sleeping with a head full of rig tuning and the uncontollable itch to draw up a Laminar flow Hull. With a fixed but variable camber rudder, which wouldn't be great to fight weather helm but ideal as a trim for a perfectly balanced boat.
Robert May is offline Find More Posts by Robert May
Reply With Quote
Old Dec 10, 2009, 07:17 AM
Registered User
Ed Morales's Avatar
Singapore
Joined Aug 2002
362 Posts
This is a video of the Singapore IOM fleet when we sailed with our buddies in Malaysia
Putrajaya Sailing Week 2009 (4 min 14 sec)
Ed Morales is offline Find More Posts by Ed Morales
Reply With Quote
Old Dec 10, 2009, 08:40 AM
FROM THE MIND OF A MADMAN
gpzy's Avatar
United States, CA, Los Angeles
Joined Apr 2007
3,240 Posts
Here are some pics from Race Week 2009 in San Diego. Wish I new the names of sailors and hulls.

http://www.flickr.com/photos/9383481...7621860252891/
gpzy is online now Find More Posts by gpzy
Reply With Quote
Old Dec 10, 2009, 09:59 AM
Registered User
Joined Apr 2002
1,860 Posts
Nice photos! What camera/lens are you using? Lots of zoom on a lot of shots and no evidence of camera shake normally means a professional set up. Thanks for sharing them.
Robert May is offline Find More Posts by Robert May
Reply With Quote
Old Dec 10, 2009, 10:05 AM
Registered User
Malaysia, Federal Territory of Kuala Lumpur, Kuala Lumpur
Joined Jun 2007
358 Posts
We've got some ESPN coverage at our Malaysia Putrajaya Sailing Week 2009
Hope Colin will be having life coverage next year ..... and i heard most of the Singaporean skipper upgrading to Pikanto
lamafever is offline Find More Posts by lamafever
Reply With Quote
Old Dec 10, 2009, 10:30 AM
FROM THE MIND OF A MADMAN
gpzy's Avatar
United States, CA, Los Angeles
Joined Apr 2007
3,240 Posts
Nikon D2H and all my lenses are 2.8 or faster.
gpzy is online now Find More Posts by gpzy
Reply With Quote
Old Dec 10, 2009, 10:46 AM
Registered User
Joined Apr 2002
1,860 Posts
Thats nice gear! Well worth the money to get a set of photos like that.
It interesting that you can pick some of the stuff I have been banging on about in some of those photos.

Have a look "carefully" at some of the photos and you will find boiling transoms and submarine noses.
Robert May is offline Find More Posts by Robert May
Reply With Quote
Old Dec 10, 2009, 12:58 PM
FROM THE MIND OF A MADMAN
gpzy's Avatar
United States, CA, Los Angeles
Joined Apr 2007
3,240 Posts
The pics can also be used on how to set up a sailboat.
All racing has limitations. Work within the rules, practice the art of sailing. And it is all fun!
gpzy is online now Find More Posts by gpzy
Reply With Quote
Old Dec 10, 2009, 03:02 PM
Registered User
USA, LA, Mandeville
Joined Feb 2005
885 Posts
Are you saying that with a separate trim on the jib, that the nose of an IOM will not submarine in a breeze? Or that I will not need a rudder that will "boil the water"?

There are ways to trim the jib differently from the main, it just involves a bit of line manipulation and pivot points. But why bother? I sail upwind or down wind. Sails in, or sails out, and I have them set up so there is almost no rudder movement needed to track a straight line.

I do like some weather helm on my boats and feel it is faster than no-helm upwind. You will not be able to detect a lift if the boat does not want to naturally head up into it.

Are there any "real" boats that are sailing with a "laminar flow" hull that you describe? Since all "real" boats have a separate jib and main trim, why do they need rudders?

With a twice around upwind/downwind course taking about 12 minutes to complete, how much time will you lose trimming your jib instead of hitting the shifts? Will you be able to manouver with another 20 boats at the starting line with a "variable camber" rudder?
hew565 is offline Find More Posts by hew565
Reply With Quote
Old Dec 10, 2009, 03:08 PM
Registered User
Joined Dec 2009
69 Posts
Quote:
Originally Posted by Robert May View Post

Here is something to think about and an explanation why I think hulls are be forced to sail backwards; The Reynolds number of water for an IOM means that effectively we are sailing in Treacle. Water is about 1000 times thicker than Air so it is my argument that hull form and what goes on under the waterline that has the biggest effect on boat speed. That is why I dislike rudders so much, they are a brake.

How many fish swim backwards? (I can't think of one) Airfoil sections, name one section that flies trailing edge first. You can't! again for the same reason (Reynolds) both nature and science dictate that the blunt end, rather than the thin pointy end goes first; and so it should be with boats, blunt and bouyant bows with every effort directed at achieving laminar flow and bring the CP much further forward were it can help absorb the power from the exaggerated rigs whose best efforts are inevitably aimed at shoving the bow under water. Unfortunately all that effort become wasted as soon at the rudder is being used to control weather helm. Bubbling boiling water off a transom is a clear indication of turbulent flow, a sign that the brakes are on.

You fellas ought to get to bed, its getting late now
Interesting thoughts Robert.

How many fish have rigs strapped to their back? Foil sections are designed to generate a sufficient lift, whilst maintaining the lowest possible seperation bubble through the wide varience of hull speeds.
The simple reason why you will not see a "cods head" type hull form successful in IOMs is that they are extremely slow unless well powered up. Combine this with a sloppy sea state in open water and you have a boat that spends its time slapping into small waves whilst a fine section bow slices through. Same in the real world of big boats. Don't think that it hasn't been tried, it just hasn't been proven to work in IOMs in any way. Now if we design a boat that had a bow that did not trim down when heeled and a rig that actually bent properly at the overpowered stage, we would not need to be on the rudder upwind at all. It sounds like you may not have been to an IOM race for a while in the UK as some good people have worked hard on the above to good effect. Ask one of them for a try.
p
pchicken is offline Find More Posts by pchicken
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion X-3D Brushless Quadrocopter, general quadrocopter, x-ufo discussion tend2it Multirotor Talk 2529 Apr 26, 2008 07:45 PM
Discussion Kong Power Packs Info And General Discussion nitroshark Batteries and Chargers 10 Jan 12, 2008 11:33 PM
Discussion Kong Power Packs Info And General Discussion nitroshark Batteries and Chargers 32 Jan 03, 2008 03:02 PM
Discussion General Discussion PLD Australia 172 Nov 27, 2006 10:26 PM
General Discussion / Training Area zax Site Chat 0 Oct 03, 2001 01:48 PM