Search found 63 matches

by Jamestj
11 Sep 2006, 13:11
Forum: Class Rules
Topic: Are crystal-free radios allowed?
Replies: 3
Views: 4713

Many thanks for that information.
by Jamestj
11 Sep 2006, 00:31
Forum: Class Rules
Topic: Are crystal-free radios allowed?
Replies: 3
Views: 4713

Are crystal-free radios allowed?

I understand that radios which transmit an ID to the receiver instead of using a specific tuned frequency rely on the receiver transmitting a reply to the transmitter. Are these legal for IOM use please?
by Jamestj
08 Sep 2006, 10:07
Forum: General IOM
Topic: Wide transoms
Replies: 1
Views: 3967

Wide transoms

Modern yachts above 10 metres have wide transoms so that an aft cabin can be fitted. Sailing reports in sailing magazines indicate that boats with narrow transoms sail better than ones with wide transoms. I think that this is because the underwater shape does not change that much when the boat is he...
by Jamestj
08 Sep 2006, 09:57
Forum: General IOM
Topic: Swimming platform
Replies: 4
Views: 5512

Many thanks. I don't mind making a boxy hull if it has a theoretical advantage. I can understand that manufacturers would be keen to make the hull look realistic since it attracts buyers. For a one-off this won't be a problem. Unfortunately we don't live near the coast and inland lakes can be rather...
by Jamestj
07 Sep 2006, 17:00
Forum: General IOM
Topic: Swimming platform
Replies: 4
Views: 5512

Full sized boats with swimming platforms have a backstay which divides so that people can get to the back and so that the wires don't get in the way. The backstay connects either side the back off the hull. I understand that a bifurcated backstay is not permitted under IOM rules for some reason. Wou...
by Jamestj
07 Sep 2006, 12:54
Forum: General IOM
Topic: Swimming platform
Replies: 4
Views: 5512

Swimming platform

Most IOMs have a forward rake resembling the swimming platform on a full sized yacht. This means that the backstay does not connect to the extreme rear of the hull and the effective hull length is reduced. Since long boats tend to sail faster than short ones, what is the advantage of a forward slopi...
by Jamestj
10 Jun 2005, 10:35
Forum: General IOM
Topic: Modifying Sanwa Super Exzes for iom use
Replies: 2
Views: 3861

Hi Rob I was fiddling with the left stick and unscrewed it quite a long way. Something went click and the stick went floppy. Seems that you don't even need to take the back off to make the changes you suggested! Still, I had better get the bits out in case they short something out. Thanks for the tip.
by Jamestj
05 Jun 2005, 00:13
Forum: General IOM
Topic: Modifying Sanwa Super Exzes for iom use
Replies: 2
Views: 3861

Modifying Sanwa Super Exzes for iom use

I have just bought a Sanwa Super Exzes transmitter and Spektrum modules but don't know how to modify the 'accelerator' stick to work the mainsheet. Can anyone help me please?
Thanks
by Jamestj
17 Apr 2005, 22:31
Forum: Class Rules
Topic: Mat'ls: keel & rudder; mast, boom, stand. rig. fittings
Replies: 13
Views: 13209

I understand that lead is prohibited in UK as sinkers for fishing lines since swans and other birds which swallow stones (to grind up food on account that they don't have teeth) tend to end up with lead in their gizzards and this causes their heads to droop. (This is not due to the weight of the lea...
by Jamestj
16 Apr 2005, 18:34
Forum: Class Rules
Topic: Mat'ls: keel & rudder; mast, boom, stand. rig. fittings
Replies: 13
Views: 13209

I have an ingot made from an alloy of lithium and aluminium. They say that this material is stronger than steel and lighter than aluminium. You can't weld it since it burns but it seems O.K. to machine. Its not that expensive for IOM use since you would only use a little for fittings. It would be gr...
by Jamestj
16 Apr 2005, 18:22
Forum: Class Rules
Topic: Mat'ls: keel & rudder; mast, boom, stand. rig. fittings
Replies: 13
Views: 13209

The keel will not be able to be made of pure lead 'cos its too soft so it is alloyed. The alloy usually has a lower density. Other metals (and some non-metals) have a higher density so they could used instead eg osmium has a density of 22610 kg per metre cubed, lead is relatively light at a mere 113...
by Jamestj
21 Mar 2005, 08:19
Forum: General IOM
Topic: Polypropylene sails
Replies: 6
Views: 6464

Thanks for that info, Ralph. Buying from a source specialising in IOM products means that they will be tried and tested in this application and won't rust or do other unpleasant things. Can anyone help me with another problem I am having please? I made a sail out of some drafting film. It looks OK u...
by Jamestj
19 Mar 2005, 01:09
Forum: General IOM
Topic: Polypropylene sails
Replies: 6
Views: 6464

Many help for the info.

Could anyone tell me where I could get some tiny grommets to put in the luf to prevent the material from tearing? I live in England so the company would have to do mail order.
I have tried melting holes in the material but it does not work too well.
by Jamestj
14 Mar 2005, 02:01
Forum: General IOM
Topic: Polypropylene sails
Replies: 6
Views: 6464

Polypropylene sails

I have a roll of polypropylene plastic sheet bought from an office supplies shop. It is clear and shiney and about 10 microns thick. Is polypropylene suitable for making IOM sails? If I stick numbers on the sails they will show through mirror image. Is this acceptable? The sails may be very difficul...
by Jamestj
13 Mar 2005, 09:50
Forum: General IOM
Topic: Deck shape
Replies: 3
Views: 4840

Thanks for the encouragement, Mr. Chairman. I have made a mock up out of builders foam sprayed onto a plywood former. I thought that a high foredeck would reduce the chance of the hull burying its nose into the water when running downwind. It would also divert the wind to blow into the foresail. I a...
by Jamestj
21 Feb 2005, 16:52
Forum: General IOM
Topic: Fixing bulb to fin
Replies: 5
Views: 6092

Hi Ralph I was thinking of sticking copper foil round the end of the fin using epoxy. The copper should be wetted by the Woods metal and presumably it would also wet tha slot in the bulb since Woods metal is mainly lead. I could heat the bulb and soften the Woods metal without fear of melting the bu...
by Jamestj
20 Feb 2005, 00:13
Forum: General IOM
Topic: Fixing bulb to fin
Replies: 5
Views: 6092

Fixing bulb to fin

It might be useful to alter the angle of the lead bulb to carbon fin. I thought about using Woods metal since it melts at 70C. I could heat the bulb and alter the angle and it should stay put when cold. I have not heard of this being done. Are there any problems using this method?

Thanks,

James
by Jamestj
14 Feb 2005, 13:49
Forum: General IOM
Topic: What shape should the rocker be?
Replies: 7
Views: 7774

Yes but .... Broad bows create drag. This drag pushes the water down rather than sideways. An equal and opposite reaction would raise the bows - perhaps causing the vessel to plane. Do IOM's gain a greater advantage by going through waves rather than rising over them? Received wisdom is that IOM hul...
by Jamestj
08 Feb 2005, 09:36
Forum: General IOM
Topic: What shape should the rocker be?
Replies: 7
Views: 7774

What shape should the rocker be?

The hull of a sailing boat really has to have its maximum depth where the fin is attatched. The fins of IOMs are invariably more than 500 mm aft of the stem. Since fish and birds and sailing boats are usually wider forward and taper towards the back, why should IOMs be different? Probably a very sim...
by Jamestj
07 Feb 2005, 22:02
Forum: Class Rules
Topic: I can't understand the rules!
Replies: 6
Views: 7414

Hi Arvin
Thanks for the reply. It seems that every sport has its own vocabulary to keep outsiders guessing. You would have thought that sheets were sails but they are in fact ropes!

Gradually getting my hang of the lingo!

James
by Jamestj
28 Jan 2005, 12:55
Forum: Class Rules
Topic: I can't understand the rules!
Replies: 6
Views: 7414

Many thanks for the help, even the Equipment Rules has pictures which are worth a thousand words.

Not 'all at sea' anymore
by Jamestj
26 Jan 2005, 23:43
Forum: Class Rules
Topic: I can't understand the rules!
Replies: 6
Views: 7414

I can't understand the rules!

I'm new to IOM and trying to build a boat. Having trouble understanding the rules, not use to terminology. Could someone explain the difference between - The lower point of a mast, the heel point and the bottom end. A mast and a spar, A checkstay and a shroud, A jackstay and a mast jack. Is a riggin...
by Jamestj
13 Jan 2005, 13:42
Forum: General IOM
Topic: Are Lithium Polymer batteries safe for use in a IOM
Replies: 18
Views: 13759

Many thanks JohnM

Your help is most appreciated
by Jamestj
09 Jan 2005, 11:00
Forum: General IOM
Topic: What is the best IOM Boat????
Replies: 11
Views: 12898

I've been looking at the results for the Euros results as published in Marine Modelling International Jan 2005. The boats you mentioned in your poll are under represented in the top twenty results. It would appear that the hull design is not really significant in the success of the boat. There is a ...
by Jamestj
02 Jan 2005, 18:20
Forum: General IOM
Topic: Are Lithium Polymer batteries safe for use in a IOM
Replies: 18
Views: 13759

Many thanks, Anders. That is a most ingenious arangement in Grahams boat. It would be interesting to see if similar advantages could be engineered in a drum winch arangement - without resorting to expensive machining. I am having problems soldering the lipo charging chip. The pins are too fine for m...
by Jamestj
02 Jan 2005, 01:02
Forum: General IOM
Topic: Are Lithium Polymer batteries safe for use in a IOM
Replies: 18
Views: 13759

Very interesting pictures Ed. :o It is gratifying that lipo cells have to be severely mistreated before they explode - but what an explosion! Don't you think that his is bound to be a consequence of having such a high energy density? Even the same energy stored chemically in say, petrol, would have ...
by Jamestj
24 Dec 2004, 17:03
Forum: General IOM
Topic: Building an "Arrow"
Replies: 10
Views: 8191

Hi Signatus Thanks for the links. It is interesting to see other people's work. Fiberglass and resin are quite easily available but web sites will do mail order quite efficiently. We would probably go for epoxy resin in your case. Although it is more expensive, it is more rigid so you would be able ...
by Jamestj
24 Dec 2004, 00:37
Forum: General IOM
Topic: Building an "Arrow"
Replies: 10
Views: 8191

Hi Signatus Like yourself I am new to making yachts so I have been experimenting a little. I have discovered that with epoxy resin you have to get the ratio exactly right otherwise it remains gooey. I also found that it can go off too rapidly unless you spread it out after you have mixed it. I also ...
by Jamestj
23 Dec 2004, 23:54
Forum: General IOM
Topic: Are Lithium Polymer batteries safe for use in a IOM
Replies: 18
Views: 13759

Hi Signatus Unfortunately solar cells aren't good at delivering high currents in bursts. Some sort of energy storage is needed and batteries are usually used. I have thought of using a solar array to charge the batteries between races since carrying a lead acid motorcycle battery around to charge ba...
by Jamestj
07 Dec 2004, 15:03
Forum: General IOM
Topic: Radio equipment
Replies: 25
Views: 21478

Modelavionics is back - probably being updated. Where do I click, Rob?

I read about a receiver which locked on to the transmitter when you pressed a button in a model car magazine a few weeks ago but I understood that was 40mHz. (the button was on the receiver, not in the magazine :x)