Questions and answers related to Azetone IOM boats and parts. The questions are from customers and from other interested people and the answer are provided by our reference sailors Jimmy and Manu.
I am seriously thinking about getting a new IOM. The Azetone is very
Could you possibly give me some feedback as to how this boat handles,
upwind, downwind etc?
Could you also give the basic dimensions of the boat: max. beam and
Anxiously waiting your reply
Re: (no subject)
I now have a bit more time to tell you about the Azetone ;-)
Azetone is a late 2004 design, and I have to say these two Swedish
guys , Peter and Johan did their homework righ, because they came up
with a boat that is a great all rounder, fast in a wide range of
conditions and very well balanced from the helm point of view.
The main design features are:
- A "V" shaped hull with max. beam of +/- 225 mm at deck level , that
reduces to +/- 170 mm at the water line. This allows the boat to
combine a narrow beam and small wetted area at low lean angle , while
adding extra buoyancy and stability when the wind picks up and the boat heels more.
- A medium transom: +/- 190mm max, that gives the boat good speed and
stability when reaching.
- A very fine entry section, that cuts through the waves, combined
with a rather curved rocker at the bow that adds volume, prevent the
boat from nose diving and makes the hull plane when speed goes up. The
exit section rocker is flatter in order to reduce drag. The hull max.
draft is around 55 mm and is located a bit more forward then what's usually found in
the IOM world.
The combination of those parameters makes the Azetone very easy to
sail and trim. The boat copes with various wind or water condition,
needing only minor adjustments and no re-assessment of the basic
There are probably on the IOM market more extreme designs , that
should perform sligthly better at the very end of the wind range (high
or low) , but I have sailed my Azetone for more than 100 hours
already and I'm still to find something to complain about....
Of course as always sail/rig trim, and helmsman ability are key
factor to the performance.
Oops and I almost forget ... the boat does really look great in my
Feel free to contact me, if you need more specific feedback or have
any more questions.
Emmanuel Simon (BEL 51)
Thank you very much for this very detailed report.
Between what you have sent me and what I read in the FAQs, I have made
up my mind. It is going to be the Azetone.
Looking to get a IOM and was wondering what you thought of the Azetone. I was wondering what you thought of the design and how it handles in light and heavy air.....
The Azetone is a design of moderate beam. At deck level the boat is approximately 230mm at its widest point but in the waterline it’s only 170mm. This gives the Azetone very good light wind performance due to a relatively small wetted surface while still being reasonably stiff when the wind picks up.
The bow has a very fine entry with a curved rocker line which gives the hull pretty much volume in the stem, making it more resistant to "nose diving", and easier to get surfing/planning in high wind. Check out the video at http://azetone.com/Azetone_IOM.mov and you’ll see how the bow rises and the boat takes off surfing on the waves on the broad reaches in Rig 2 conditions!
One thing I’m really pleased with is the balance of the boat which is almost always perfect. The only time I’ve to change the trim to restore balance is in really light conditions (sub 2-3 knots of wind). Then I just ease out the jib a couple of degrees to restore balance. As with every IOM design, tuning the rig right for the conditions is the key to boat speed.
I’ve raced my Azetone several times against other designs and I’ve found my Azetone to be most competitive (actually faster sometimes). So it’s not the design that holds me back! It’s the trimming of the rig, to find the perfect setup and the tactics on the race course of course!
To sum up I find the Azetone to be a really all round and fast design, which is easy to handle in every condition.
Jimmy Hellberg, SWE 17
First: I like the idea of having adjustable track for side stays rather than fixed eyebolts - (and also for fixing jib). The track that I listed (330 mm) is long enough so we can cut it to three or four pieces
- also We are going to more simple deck layout so I edited the list of parts that is included.
Sorry to say but it really doesn’t make any difference to have deck tracks for the forestay and shrouds. When I built SWE 17 and SWE 16 I felt that I didn’t want to have any limitations regarding the trimming of the boat since we where new in the class and the Azetone where a pretty new design too. But now I know differently. We have now sailed these boats one season and tested a lot of different trims in various conditions. We have even tested four different fins including Bantocks ones. All the testing has really paid off, our boats do match Cockatoos in speed . I must say that Peter and Johan have really done their homework on the Azetone design. The setting we have found working best regarding forestay and shrouds attachment point is exactly as the ones on the plan so it’s only just a waste of time and money to mount deck tracks instead of eyebolts. I have however moved the mainsheet post and jibsheet attachment point a bit forward to harmonize better with the shorter travel of the sheet line when using an arm winch. This little adjustment is really not necessary for the jib since the jib is always sheeted out like 10degrees or more (again making a deck track overkill), but it is for the main.
I think all IOMs are extremely sensitive to different sail trims, i.e. mast rake, sheeting angles, sail twist, etc, at least the Azetone is. It’s also pretty important to have the right trim on the ballast so the transom just skims above the water, try this out in a tank or on a really calm day. These two parameters are the key to make the Azetone sail on its full potential, and then it’s really up to you if you don’t win…
If you want to use deck tracks anyhow I’ll be glad to answer any questions you might have regarding my mounting.
Good luck with your new Azetones! Regards
Thanks for the comments Jimmy!
It's then easier for us to go with eyebolts...
How much does the sheeting servo placement affect to fore-aft balance? our plan is to place the servo under foredeck...
Is the balance adjusted only by bulb fore-aft -placement?
Our plan is to use hitec HS 5745MG servo for sheet...
There are many ways to make the sheeting work flawlessly, here’s how I did:
A year ago the HSR-5995TG servo was brand new and untested in our applications, but I felt the servo would have several advantages with its power, lightness and small size. So I figured the risk was worth taken. Compared to the HS-5745MG, the HSR-5995TG weights 99g less and pulls 6kg/cm more on 6.0V, the facts speak for themselves. I have used the standard sail arm from the HS-765HB servo. It’s something like 11.5cm long making mounting in front of the mast impossible. So I mounted it approximately 12cm behind the finbox, enabling the arm to swing its full 180degrees (Another advantage is that you don’t have to reprogram the HSR-5995TG to swing 180degrees). Since the HSR-5995TG only weights 62g this placement have minimum impact on the balance of the boat and makes the sheet arrangement less complex. The only disadvantage with this placement is that it complicates the mounting of the Mainsheet post. I solved it by using a transverse mounted aluminium bow instead, witch actually is easier to move if needed. I have mounted the batteries just in front of the mast on a Velcro tape that runs 20cm towards the bow, making it possible to move the weight forward in light wind, lifting the transom a little bit more for reduced wetted area. The class rules don’t permit moving any corrector weights so moving the batteries is the only way to work around this rule, getting an edge over the competition! Hence the servo is so light you’ll have at least 100g extra to put in the movable batteries. Also the Azetone hull has its deepest point just in front of the mast making this the best location for the heavy batteries. In the beginning of the year I used a 4.8V battery pack (the HSR-5995TG is rated to 18kg/cm @4,8V). In really overpowered situations on the run with the no1 rig, the servo sometimes failed to sheet in. Now I use a 6.0V battery pack witch powers up the winch to 24kg/cm which is more than enough even in the toughest conditions. Due to the arm being in its most forward position on the beat an wise versa on the run there is no load whatsoever on the servo on these two main legs resulting in a minimum of power consumption. On a 6.0V 2300mAh battery pack I can sail two days in a row without recharging. In up to moderate conditions on a flat run the HSR-5995TG enables me to jibe extremely easy since the speed and power simply swings over the main and the jib synchronously by a small in and out movement on the stick with no need to make any course corrections, a real advantage on the run! But you have to be careful when rounding that bottom mark, its really easy to sheet in way to fast ant stall the sails, you have to move the stick really slow and gentle.
It is not critical to have a perfect side support for the mast. Off course it shouldn’t be allowed to flex freely, but a play on an mm or so doesn’t make any difference. Peter supplied me with an 8mm aluminium pipe which gives the mast rake screw adjuster a really snug fit in all directions making it impossible for the mast to move more than one mm sideways. I know Bantock don’t make this type of adjuster anymore but I’m sure you can make an equivalent solution anyway. You can also just add some material to the inside of the mast tube so you get a snug fit on the sides of the mast.
No I don’t believe there is no exact tuning guide available for the Azetone. Since many of the Azetone owners are using different fins, slightly different fin positions and rake, different sails and different sail trim, and have different preferences and needs regarding weather helm, etc, etc, just to have what they believe is the advantage on the opposition, there are no chance for Peter to make an accurate guide that would work on every Azetone. The good thing about the Azetone thought is that it is extremely neutral on the helm, no sudden surprises like on some designs, which makes the Azetone real easy to tune. I use Bantocks so called One Design Rig, and have built it and tuned it accordingly to the instructions applied. The one thing that is more important than any other on a 11.0mm diameter mast is to get the mast pre-bend exactly correct for it to match the luff curve of the main when the backstay is tensioned and to get enough forestay tension without bending the mast to much. Due to the stiffness of a 12mm diameter mast it’s not as sensitive for the correct pre-bend which is making the tuning easier, but the 12mm mast has added drag, theoretically anyway. When the pre-bend is correct it’s really easy to set up the main to a nice wrinkle free shape. To get at good basic trim I lay my boat on the floor, so that the gravity makes the sails twist, and then I adjust the kicking strap so that the top batten is parallel with the bom the same goes for the jib. Only in really light winds do I have to twist the sails more, otherwise this setup is perfectly balanced with the mast flex, enabling the leach to automatically open just enough in the gusts, producing more speed and less heel. I then adjust the sheeting angles, on the jib I use 12-10degrees and on the main 1-3degrees. If the boat has to much or too little weather helm, adjust the mast rake accordingly, and then you’ll have to re tune the twist and sheeting angles again. I have made marks on my backstay and on deck at the mast tube so I know I exactly where my reference trim is.
>Date: Fri, 05 Jan 2007 17:59:59 -0500
>Jimmy, how does the Azetone sail in lighter air? Thinking of getting one here in the US
>Thank you very much for your response
For light wind condition, theoretically and typically a narrow boat will always be faster than a beamy one, all other things equal. The Azetone is a design of moderate beam with bias towards narrow. At deck level the boat is approximately 230mm at its widest point but in the waterline it’s only 170mm. This gives the Azetone very good light wind performance due to a relatively small wetted surface while still being reasonably stiff when the wind picks up.
To sum up I find the Azetone to be a really fast and all-round design, which is easy to handle in every condition.
Hope this helps!
Jimmy Hellberg, SWE 17
Subject: Trim under no 2
Date: Sat, 6 Jan 2007 22:38:54 +0100
I got your address from the Azetone site.
Recently we were sailing under no 2 rig (for the first time and I had a big problem with pointing. As long as the wind was constant and hard there was no problem. Near the shore where the wind was much less the boat had a very strong tendency to make an arc to leeward almost going downwind on his own. Especially on starboard tack.
What I did to improve pointing was:
Open the slot, close the mainsail twist, rake the mast but pointing stayed poor.
I also find the boat very neutral under no 1. You have to really exaggerate to get the boat pointing to strong.
The last thing I think of now is to put the bulb more forward. It is now standard according the building instructions. The rake of the bulb is to strong with 3,5 degrees. My mistake. So I will put the bulb forward by 1,5 or two cm and put the rake on 1,5 or 2 degrees.
Please advice me what to do and please tell me how you find the boat.
Thank you in advance.
Sorry to hear the about your problems!
Fortunately I think you can get it up to speed with a little tweaking since I find my Azetone very competitive in every condition!
This is how I setup my Azetone:
The Hull & Keel
First of all you’ll have to adjust your bulb and/or the batteries and ballast so that the transom of the boat just skims over the water when lying still, approximately 1-2mm over the surface. The water must be absolutely calm when you do this so the best is to do this indoors in a tank. The bulb cant should be just as you mentioned 1,5-2 degrees. In really light winds you can experiment with moving the batteries even further forward so the transom lifts a couple of mm extra (this is not a must but I’ve found it to give me a little extra edge on the competition). I’ve placed my batteries just in front of the mast base on a long velcro since the hull is deepest there and it is really easy to move the batteries forward in light wind. By light wind I mean 1-4 knots of wind, i.e. when the boat barley heels. The finish of the hull and the appendages should be as smooth as possible. These small boats move relatively slowly so much of the wetted area are running with laminar flow, especially in light wind conditions, and we don’t want that flow to break up into turbulent! Therefore I wet sand with 600 and 1200 grit paper and finally polish to a mirror finish. I’m also very particular about getting a snug seal between the rudder and the hull and the keel and hull so there’s no turbulence and extra drag there. This could really make a difference in underpowered conditions.
Just before I put the boat into the water, I always check the rudder, it has to be centred! This is a common reason the boat have different balance on different tacks!
The rig and sails
On an IOM you have three rigs, therefore you’ll never have to adjust the shape of your sails for "least drag" as you would on a big boat or dinghy when you are getting overpowered. On an IOM you simply set your sails to the "most power" shape! And when it gets too much, you just put on a smaller rig! There is one exception off course, and that is in really light winds when the boat doesn’t heel much, or at all. Then you can assume that the wind is mostly laminar, and laminar flow has a tendency of not being able to stay attached to heavily curved sails. I’ll get back to that later. Anyway most of the days you really need only ONE setting!
My reference trim is exactly as seen on the supplied pictures. The setup is exactly the same for both rig 1 and rig 2! Probably for rig 3 as well but I’ve never used it. I use the Sailsetc one design rig and I’ve build it according to their specifications.
Let’s start with the main. I sheet the main as hard as possible without loading the leach, i.e. when fully sheeted the twist may not decrease due to the tension in the sheet, this is very important! The sheet shall only control the angle of the boom, not the leech tension and twist. That is the function of the kicking strap (boom vang). To get this as good as possible the mainsheet pole must be as close to the boom eyelet as possible. When this functions properly the boom will have an angle of attack of approximately 1-2degrees when fully sheeted. To minimize the hooking of the leech in the lower sections I tension the outhaul so I only get one finger in between the foot of the sail and the boom.
Adjust the backstay tension and the mast-rake screw to bend the mast to a shape that perfectly fits the shape of the luff of the main. The fullness of the sail at the upper batten should be fairly flat, a 10-12% camber is perfect. I found that too much shape in the top of the main will only slow the boat down. If you get so called over-bend wrinkles in the sail before you have 10-12% camber, the bend of the mast does not match the luff of the sail. Small wrinkles can be removed with some extra Cunningham tension. I mentioned I use Sailsetc sails and to get the perfect shape with the right forestay tension you’ll need to pre-bend the mast according to their specifications. I don’t know how it is with other brands but I suspect it will be similar.
Now, lay the boat on the floor, preferably indoors where there is no wind so gravity only is pulling the sails. Adjust the kicking strap so that the end of the top batten is parallel with the boom, this is approximately 10 degrees of twist. Less twist than this will only slow you down and add leeway (never use less twist). More twist will sometimes make you go faster but point lower.
Experiment with the mast-rake screw so you get a feel for how this affects the shape of the sail. If you put more pressure on the mast you’ll get less twist and more shape, especially in the lower parts of the sail. You’ll need some tension on the mast-rake screw together with the right pre-bend to achieve the right tension in the forestay and to make the whole rig just enough "springy".
Since a fractional rig has the forestay attached somewhat down from the top of the mast the rig will adopt itself when a gust hits. The power in the sails will bend the mast (the most of the bending will be in the fore-aft direction provided that the shrouds have enough tension) and more bend will flatten the main and make it twist more. The added tension in the main leech also means more tension in the forestay and hence a flatter jib. So a fractional rigged boat will be very dynamic in gusts and lulls! The stiffer the sailcloth is the better this works and relatively to the forces an IOM has very stiff sailcloth. That is why you can set up your trim on your IOM indoors with no wind with just gravity pulling on the sails. I always have my boat laying on the floor and watching from the top of the mast when trimming my sails. This works really well since you can easily "aim" along the battens to see that you have the correct twist and shape.
And now some words about the jib trim. The right forestay tension is crucial for two reasons. First, if it sags too much the boat won’t point (if it’s has really bad tension the whole luff of the jib will flutter). Second, too little forestay tension means too little tension in the jib lift, which means that the jib will twist away in the gusts and the boat could develop a "snap weather helm"!
The jib should be sheeted 8-10 degrees further outboard of the main. If the slot gets smaller than this you’ll loose speed and the boat will be dull and insensitive and it will actually point lower so be careful! To far out and you’ll loose the balance and the power of two sails cooperating.
You should also make sure the leech of the jib is as close as possible to the mast and main to optimize the slot effect of the jib and main working together. But be careful, moving the jib swivel to far forward will reduce the tension on the jib lift. This is never a problem in light winds though.
Again, to get the correct jib lift tension I've attached my jib swivel as specified by Sailsetc.
I set the jib outhaul so I’ll get approximately 10% camber in the lower parts of the jib. The tension of the luff has a really big effect of the camber and draft position. I tension the luff just until I have some small wrinkles left in the jib luff. Since the sailcloth is so stiff and the eyelets in the head and tack are relatively far behind the fore stay (since this is really small boats) tensioning the luff will only flatten the entry of the jib and prevent the entry from rotate and get a round full shape, which is the opposite against what we want so be very careful with the luff tension! This is one thing which you cannot really se without wind in jib.
Take a hair dryer (without heat!) and experiment!
The twist of the jib should be set exactly as the main, i.e. the top batten of the jib should be set parallel with the jib boom so it follows the twist of the main.
I like to have my boat set up with just some weather helm so I have to make a small correction every fourth boat length or so, in this way I never misses a lift and the boat feels alive and sensitive. To get this just right you have to rake the mast forward or aft. If the mast points forward when you’ve got the right balance your keel is to far forward and you’ll have to angle it back a little. After you have raked your mast check the trim from the beginning!
When I have got everything right I mark every setting with a marker on the booms, backstays, forestays, shrouds, sheets, jib lift, etc, etc, so I quick and easily can set up my reference trim!
Now to the only exception from the reference trim.
In really light winds I use more twist and I also try to make the mainsail even flatter (approximately 8% camber in the top of the main) to not stall the main. I do this by easing on the mast-rake screw, sometimes even by tensioning the backstay a little extra. But be careful you don’t want over-tension wrinkles in your main, and it is not advised to have a large amount of Cunningham tension in light winds. If its waves an light wind try with lots of twist (10-15 degrees more than ref), remember to twist the jib just as much.
I always ease out the jib a couple of extra degrees when it gets really light. This opens up the slot so the wind can blow trough without slowing down (slow moving air has even harder to stay attached to the curved surface of the sails). This also restores balance since the boat will get a little lee helm when the wind drops.
The trick to get the boat going in really light winds is to sheet out fully, the sails will then open parallel to the wind. Then you’ll sheet in just a fraction from that position. The boat will start moving. Head up and sheet in slowly until you are on a close reach or even close hauled. You can often point much higher than you think. If you lose speed, sheet out to find where exactly the wind is coming from.
Your pointing problems with rig 2 (mostly on starboard tack), could be due to:
- Rudder not centred
- Mast not in the middle of the boat (leaning to port) Jib does not have same travel on port and starboard side Not enough shroud tension Jib boom too far forward Too little twist in Jib Main too open sheeted
If your boat feels very neutral as you described with rig 1, it could be due to:
- The slot is too small
- To little twist
- To much camber in top of main
Try to set up your boat as I described and as the pictures shows and I think you’ll find her flying like ABN AMRO ONE!
Really hope this helps!
Sent: den 8 januari 2007 09:21
Subject: Azetone and very light winds
Firts time i raced the azetone i got impressed. It was around 15kn of wind
and very choppy sea. The boat carried nº1 rig to the extreme without
problems and sailed with nº2 perfectly balanced. Last regattas we've
suffered from very ligth and rolling winds and the boat seems to dislike it
more than other designs. The problem is that it takes a lot to the boat to
start from zero. If i sail it near i can see how it displaces lateraly
during a while until it gets enough speed to start sailing ahead.I've tried
different sail suits (from housemartin and blackbagick), and trimmed the
boat in every manner. No way. It seems like it suffers a lack of lateral
resistence. In fact i compared the surface of finn and rudder with that of
other boats and realized it was much lesser.I'd like to know if this is a
normal tendence of the boat or if i perhaps i'm doing something wrong or
missing anything. If this were a normal tendence, what i wouldn't mind as
the boat in normal conditions runs like a shot, could i counterbalance it
with a bigger rudder to be used when very light wind conditions are
expected?. Many thanks.
Light wind sailing is always a challenge and it demands more from you as a
sailor. In all other conditions a well balanced boat will sail it self (more
or less) but in light winds this is not the case. In Light winds you really
have to steer the boat actively, up and down to find the shifts, since
there’s is not enough power in the wind to balance the boat.
Light wind conditions are where the Azetone should be most competitive. But
there are many parameters that must be taken in to account to get at good
In your case, these could be some of the issues why you find your boat
performing badly in light wind:
*You are sheeting too hard (stallling the sails), ease of the sheets and/or
point higher, be extra careful when starting from zero and after tacks!
*There is not enough twist in your sails.
*The slot is too narrow, ease out the jib.
*The main is to full, flatten it out.
*The stern is dragging, move some weight forward to lift the stern.
Last, but not least important, in light winds, the finish of the bottom and
appendages really do matters!
Also check out my latest answer at the FAQ page on www.azetone.se
It’s a pretty complete guide with detailed pictures of how I set up and trim
Let me know if this doesn’t help you!
Jimmy, SWE 17
To: "Jimmy Hellberg" Subject: Topping lift
Date: Tue, 20 Feb 2007 16:20:28 +0100 (CET)
I usually sails inland in not very windy places, but when sometimes the wind picks up , my topping lift has a tendency to hook up at the spreader bars when tacking.
What solution would you recommend to prevent the problem ?
There are two main reasons why the topping lift gets stuck in the spreader, and it’s usually a combination of both, which is a topping lift line of too thick diameter, catching air and not enough tension in the same. The more tension you have in the forestay and the greater the offset between the forestay attachment point on the jib boom and the jib swivel, the greater tension in the topping lift.
To get the right tension in the forestay I recommend to pre bend the mast according to Sailsetc standards, i.e. the upper half of the mast should have a smooth bend, 40mm forward (rig 1). It’s pretty tricky to get the pre bend right so the mast curve perfectly matches the luff of the main when the backstay is correctly tensioned. Be careful when bending the mast, it’s easy to break!
The attachment point of the jib swivel is a compromise. Theoretically the further forward on the jib boom the swivel is attached the higher the boat can point. But the further forward the jib swivel is attached the lesser the tension in the topping lift will be. And if there’s not enough tension in the topping lift the leach of the jib will twist away in an uncontrolled manner in the gusts, which might lead to a nasty weather helm.
So where to put the jib swivel?
Provided you have an 11mm mast with the 40mm forward pre-bend so you’ll get the right forestay tension, a good reference is to place the jib swivel 88mm (rig 1) behind the attachment of the forestay on the jib boom.
So now you’ll have adequate tension in the topping lift, but that may not be enough. Still a thick diameter topping lift will catch a lot of air and bend/flutter so it may still hook a spreader or at least temporarily change the trim of the jib (increase twist). Therefore you should use a really thin (low stretch) line for the topping lift, making the wind drag as low as possible. I use Sailsetc 0,5mm Dyneema for this purpose.
So now you’ll have adequate tension in the topping lift and a thin, low drag line, and hopefully your problem is gone, but what if it’s still not? Well, if you want to be sure, you’ll have to put a jib lift restraint line on to the jib. That is a line that is attached on one side on the jib leech and it runs around the topping lift line and back to the other side of the leech, preventing the topping lift to "fly away" and catch a spreader (se the attached picture). If you decide to use one, I’ve found it best to place it 10-20mm above the spreader height. It should just be long enough not to prevent the leech from twisting. To set it up I lay my boat on the floor and adjust the jib to the correct twist, then I set the length of the restraint line so the leech only has a small tendency to hook at the point of the restraint line. Don’t make it longer than necessary or it won’t help.