IOMICA Forum

Many thanks for that information.

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?

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...

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...

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...

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...

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.

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

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...

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...

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...

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...

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.

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...

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...

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...

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

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...

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...

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

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

Not 'all at sea' anymore

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...

Many thanks JohnM

Your help is most appreciated

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 ...

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...

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 ...

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 ...

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 ...

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...

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 )