Has anybody any information about a dual purpose 36? Is it feasible to use the same boat for vane and radio? I presume you would have to arrange a plug-in rudder and separate mast locations but somebody must have done it...

Gary

Gary

I used a dual-purpose system on my A-Class and Marblehead for many years through the late 1990's and early 2000's.

The system I used was to install 3 separate tubes at appropriate distances at the rear of the boat.

For Vane Sailing, I used 2 tubes that were installed through the hull and deck of the boat. They were used to house a detachable skeg and rudder system. The skeg was securely tightened to the hull, ensuring correct alignment with the hull and fin. 

For Radio Sailing, I used the traditional rudder tube but not all the way through the hull, this kept the servo linkages under the deck and maintained water tight integrity. I would use deck patch material to cover tubes that are not in use.

When swapping from Radio to Vane, you have to spend time removing the radio equipment and all associated sheeting prior to your Vane setup. Its time consuming but necessary. There is no need for moving mast positions, this would make the system more complicated and with no performance gain.

If you’re going to make a dual 36, you will have to consider making the bracket which supports the Vane gear removable from the transom.

Good Luck

JT

I'd like to use shroudless carbon masts on the 36 that I'm building. Should I use step tapered or straight tubing? What sizes would anyone recommend?

On 18/02/2025 at 13:16, Gary Dickens said:

I'd like to use shroudless carbon masts on the 36 that I'm building. Should I use step tapered or straight tubing? What sizes would anyone recommend?

Carbon masts are not allowed by class rules,

On 22/02/2025 at 22:18, andywright1 said:

Carbon masts are not allowed by class rules,

Hi, I can find no mention of material restrictions in the rules, could you tell me where that is written?

Gary

I tried to find where that had a vote a few years ago, but can’t find the information now, it would be worth emailing Martin Dovey, the class registrar. I think most of the skippers are using alloy masts. When I saw your post I did read the rules and couldn’t find any restrictions on masts. I have just ordered a new boat, and just assumed it was alloy or wood only

Hi Gary, Ive read all the messages on this forum from 2017, when a study was carried out about carbon tubes, there was a lot of opposition, and some evidence for, I see the mast restriction was in the class rules F.1, however I have read the rules a few times and it does look like this restriction has been lifted, but don't quote me, I am having a 36R built for me by Martin Dovey, and the choice of carbon masts have never been mentioned, all the videos I have watched, there aren't many, on you tube the boats all seem to have alloy masts. Sorry if I have created doubt, but I would like to see the 36R class expand and didnt want you to build something you couldn't race.

12 hours ago, Gary Dickens said:

Hi, I can find no mention of material restrictions in the rules, could you tell me where that is written?

Gary

 

Edited February 24, 20251 yr by andywright1

Thanks for the replies Andy, I also read all the discussion about carbon masts and there didn't seem to be a conclusive decision made. When I looked at the rules, there is no mention of materials at all so I presumed the decision was made to allow carbon. 

My interest in using carbon masts is in wanting to do away with the faff of having shrouds and was wondering what diameter carbon mast would give sufficient stiffness for that.

Hi Gary,

Having used carbon masts on mini 40 trimarans, you would certainly be ok with 12mm, and I would like to think 10mm may be OK, years ago I used to make sails, Windpower Model Yacht Sails, mainly for mini 40's, but also for other classes, micro magic etc, I am just starting to make my own sails for my 36R when I take delivery, anyway keeping to the point a chap from Burnley or that area, used to mould a very affordable IOM and also a 10Rater, he would do the hull and sails as a deal, and they were nice boats for club level sailing, any way he retired and I had bought about 20 tapered carbon masts from him, 2m in length, at the bottom they were about 13mm, and tapering to 8mm, I wish I had some left, but I only have one on a boat I built a few years ago, but they would have been ideal. You can taper a mast by starting at 12mm, then fitting a 10mm inside the 12, and an 8mm inside the 10, quite affective, you have to wrap the tube with carbon tow by the joins, these tubes are all available from PJ Sails and I think Sails etc. For a 35R it would certainly be worth starting with about 1m of 10mm, and the remaining in 8mm for a 36R topsuit if carbon is allowed. For lower suits I am sure 10mm would be OK, I am going to use 1mm alloy on my own boat. All the best with your build.

For info the vane 36" boat I race has alluminum half inch diameter shroudless rigs on the 2 smaller rigs.

 

They work fine.

I emailed the class registrar and he informed me that carbon masts are indeed legal for the 36 class boats.

Thanks all.

Gary

On 22/02/2025 at 22:18, andywright1 said:

Carbon masts are not allowed by class rules,

That is incorrect. Rules changed a few years ago! Find the rules here..

https://www.mya-uk.org.uk/wp-content/uploads/2019/05/36_Class_Rule.pdf

For reference I used 10mm for my 36 masts, with 8mm above the shrouds on the tallest rigs. I’d say you’d want a bit of give so using high modulus tubes would be too much. I sourced some from easy composites that has worked fine.

Edited February 26, 20251 yr by Dave Kent

21 hours ago, Dave Kent said:

That is incorrect. Rules changed a few years ago! Find the rules here..

https://www.mya-uk.org.uk/wp-content/uploads/2019/05/36_Class_Rule.pdf

For reference I used 10mm for my 36 masts, with 8mm above the shrouds on the tallest rigs. I’d say you’d want a bit of give so using high modulus tubes would be too much. I sourced some from easy composites that has worked fine.

Thanks for that info, I was thinking of using the roll wrapped tubes from Easy Composites. So you still need shrouds ona carbon rig then? That is what I was hoping to avoid...

Edited February 27, 20251 yr by Gary Dickens

You probably wouldn’t need shrouds if you used standard mast tube from PJ Sails, or Sails etc, you could split the mast into 3 equal lengths and use 12mm for bottom, 10 mm for middle and 8 mm for the top, you slide the tubes inside each other approx 2 -21/2 inches and wrap the lower tube top 2 inches with carbon tow, it looks ok if you do it tidily, I have just been given a Marblehead top suit swing rig which was actually 14mm to 12mm to 10mm. I used to use 12mm tapered to 8, but in one length not joined, on a mini 40 tri, the top suit was 2.2metres, shroud less, not a problem. So I do think you would get away with 12 or 10mm right through, with no shrouds. It’s a lot easier if you can see what you are buying in the flesh so to speak.

6 hours ago, Gary Dickens said:

Thanks for that info, I was thinking of using the roll wrapped tubes from Easy Composites. So you still need shrouds ona carbon rig then? That is what I was hoping to avoid...

I used this stuff (and the 8mm)

https://www.easycomposites.co.uk/10mm-roll-wrapped-carbon-fibre-tube-metric
 

I didn’t bother using tow on the join, just a small bit of mylar tape on the end of the larger tube. You could use a strip of black dacron also. 
 

I only use shrouds on my #1 and #2 - with PJ clip on spreaders. #3-6 are shroudless. For reference I have a 12mm stub in the boat which has the kicker on, the 10mm section drops the full depth of the mast tube into the bottom of the boat. The mast has a wrap of mylar tape to stop the gooseneck riding up.

 

Edited February 27, 20251 yr by Dave Kent

There are two basic types of carbon tube, roll wrapped and pultruded.  They have quite different characteristics.  Pultruded tubes have all the fibres running in the same direction (longitudinal) and hence are very much stiffer in bending than roll wrapped tubes.  Pultruded tubes would seem to be obvious choice for a mast but they do have a couple of issues.  Firstly they have very little strength in the circumferential direction and will split as soon as look at you.  You must reinforce the outside of any joints and the top and bottom.  If you haven't got any carbon fibre cloth, then whipping them with strong thread and superglue works well.  Secondly, because of the way they are made (pulled through a die - hence the name) they rarely fit inside one another.  I turn the outside diameter down on a lathe.  If you are going to risk drilling them then you must reinforce them first.  Roll wrapped tubes are much more robust, you can drill holes in them and they usually telescope nicely.  I use pultruded for masts and roll wrapped for booms.

There are several sources for both types and you can buy pultruded tubes in 3m lengths (I have a 1 piece 10R A rig mast).  Not all carbon fibre is created equal and the fibres themselves can have different properties.  The tubes sold by Sailsetc claim to be stiffer than standard ones - they certainly cost a lot more.

Diameter has a big impact on bending stiffness.  The stiffness increases as the fourth power of the diameter so a 12mm tube is about twice as stiff as a 10mm tube (all other things being equal).  Shroudless rigs obviously have lower windage, but a thin mast with shrouds can be a viable (and cheaper) option.

If you want to see how much your mast bends off then just sail close hauled towards yourself in a breeze.  Also, if you get a crease in the mainsail from about a third of the way up the luff to the clew, then this is probably caused by excessive mast bend.  I ended up with diamonds on my Marblehead A swing rig to cure this.