IOMICA Forum

I registered here some years ago re. getting a lowly project back on the water, but 'life' distracted me for some time, until this year. My local club are a fantastic bunch of ladies and gents, full of advice and welcoming-ness.
But always good to be able to pick people's brains any time of the ...

A few questions on battery power for receiver+servo/winch - inputs would be received with interest:

What battery capacity (and voltage) do people use?
NiMH, or LiPo?
What peak current is needed?
LiPo has a better energy density than NiMH - are there 'power packs' available which will fit in a ...

Thanks Dave.
I've done some more trawling around, and am reading about 'jacklines'/'luff-lines' on round/sleeved masts.
For others looking into the topic like me:
http://www.onemetre.net/Build/Jackline/Jackline.htm
http://modelyacht.blogspot.co.uk/2014/01/iom-new-rig.html [I think this guy refers ...

I'm wondering about the choices on spar sections (round/groovy) and diameters. Can anyone give me pros and cons of the various options?
Thanks.

Edit: I do realise that a larger diameter is likely to be (subject to wall thickness) stiffer than smaller and that, in any case, the sail cut should be ...

I need some help please.



Yes
A 6mm rake, and after some filing, surely can't be right - that is a lot . Have you checked with them though? It'd surely be weird if this was their normal quality level, so maybe it was just a duff batch? [a Friday afternoon run...?].
It's all small businesses in ...

David L Alston wrote:Fellas /

....

Thanks David. That was the type of reply I was wanting/expecting!

(Annoying that some of it should be down to over-loading FETs - jeez there's so many to choose from, can it be that difficult to pick one up to the job?!)

What response did you want or expect ?

… Wow you have got a bargain there my old china plate. We are all going to rush out and fit one of those for sure. Why did we not think it before !!


Well, something a bit more technical, I guess - something about its spec which identifies a reason for ...

David L Alston wrote:The only drawback being, apart from the postage cost.. is that it will last about 5 minutes in an IOM at the top of A rig conditions.

Oh... what makes you say that?

I've haven't had the time on this project lately, so I can't give 'real' info, but I've purchased a http://www.mxcomponents.com/en/winches-drums/12-servo-winch-11-ay.html . (Annoyingly the postage was nearly as much as the servo itself, but hey-ho!).
Fits into the existing tray (in fact, is a bit ...

Just an update I have purchased a Hitec HS-5495BH and tried it in my elderly TS2. Whilst it appeared to work fine, there was a small amount of interference with the RMG winch as a result of which I have gone back to my trusty HB325 for the time being.

RMG recommend only a standard non digital ...

Have come over all impulsive and ordered a Hitec HS5495BH - digital, 7.5kg-cm@7.4V, 0.15sec, standard size. Seems a reasonable spec, and as David rightly points out, it's the Herbert on the tiller that will be a key factor.

Yep, I'd been looking at the digital for the position repeatability. And I've got a winch and Rx that will run at 7.2v so it would make sense for the rudder servo to also, otherwise it means dropping to NiMH's or using a regulator - weight & space either way.
Came across a low-cost Hitec digital ...

The plans for my [ageing] Nimbus show the sheeting coming through at deck-level and through a fairlead to the boom. Other pics I've seen of (probably more recent) IOM designs often feature a ~2cm pillar fairlead through which the sheet exits. I was drawn to that at first - it keeps the pull purely ...

Colin in the Shiraz I have ordered they fit an HB325 which has 3kg.cm of torque - I can only assume the builders have experience to suggest that this servo is sufficient:

http://www.servoshop.co.uk/index.php?pid=HITHS325HB&area=Servo

....

There are a lot of experienced IOM sailors on here, guys ...

What I've got in there at the moment (i.e. it came with the boat) is a Futaba S148 - specs I've found online say this is 3kg-cm @6V).
[That reminds me - if it's a 6V max then I maybe need to consider voltage as well as torque, if I stick a7.4V LiPo in there!]

and let's look at the ever helpful Mr Alston's last post:

We are all painfully aware of who built the boat, how you acquired it on E-bay. We have all endured the painful commentary and slow progress together with the saga of weight , servo mounting and all battery purchase.

For the life of me I ...

Is there any perceived/generally-accepted wisdom on the amount of torque an IOM's rudder servo should be able to impart?
(In case it's relevant: CSA of my present rudder is ~130cm2; 7cm leading-to-trailing edge ['chord length'?], with shaft @1.5cm from leading edge).
Ta.

Thanks

Thanks.
I'm a digital/software engineer, but working in the field of RF products - it is indeed a black art! Yep, 2.4gig is readily absorbed by water - that's why we use it to cook with ;)
The questions re. antenna placement was for the polarisation: 90 degree antennae both lying flat would be ok ...

Just wondering what's the accepted practice for putting holes in a plastic radio pot for the servo wires (best to bring them through high in the pot, or towards the base?), and for sealing the apertures after?
Also, for a 2.4GHz radio, is it the norm to route the antenna up through the deck to get ...

Thanks for the info Levend.
The plastic (?) gears seem a bit of a concern, but as you say - it is at a much lower price than RMG.
I think my next step is to decide whether I dare slice out a big section of aft deck to give me access for this style of winch - currently, I only have space for a Hitec ...

Thanks David.
Yes, I'll be racing. I never enjoy pottering/day-sailing in a dinghy and don't expect model yachting to be different - racing is what gives the enjoyment and challenge, for me.
I am cautious about the time I'll be able to find however, hence the wish to be conservative with the initial ...

Lol thanks. Space for an arm is a problem though - it's a Nimbus with very limited servo room: less than 4"x3"

Thanks John,
I'll have a look for the modifying route (or if you can point me to a link or search term...?) - re-engineering summat isn't a problem, so that could certainly be a way forward.
I'd imagine smooth mark rounding is wise anyway, rather than slamming the helm down and sheeting in like a ...

I'm trying to choose a drum winch servo for a hull I'm refitting. It's an old boat and design, and my first, so at this stage I don't want to go to the expense of an RMG. The Hitec HS-785HB is obviously very low cost, but how much of a problem is the slow speed - for a beginner, club sailor (albeit ...