Interesting reading about a composite lower mast for the Radial

thieuster

Active Member
Thread starter #3
From Bruce Taylor's FB page:

"Protoype Laser Radial Composite Bottom Section

Any development that reduces the cost of ownership of a Laser, or any boat for that matter, has got to be a good thing, right? We have recently seen the introduction of the composite top section which is now in use across all three of the Laser classes, i.e. Standard, Radial and 4.7 rigs. The new top section has eliminated the perennial permanent bend that required the regular costly replacement of this component for all Laser sailors, irrespective of the rig they used. In addition, there has also been the recent implantation of the Mk2 Standard radial sail, which addressed the longevity of the old cross-cut sail. It seems to have won instant approval, even at club level, with the majority of sailors having chosen to swap to the new sail.

There is another issue that Laser (ILCA) have needed to address and thankfully a solution for this now appears to be just around the corner. This solution will, I am sure, have Radial sailors all around the world cheering. Ever since the original implementation of the Radial rig for the lighter Laser sailor, there has been the issue of permanent mast bend in the lower section. The introduction of the turbo vang that made the Laser somewhat easier and more enjoyable to sail, only exacerbated the problem. Installing an insert to effectively double the wall thickness from 2mm to 4mm at the overbend stress point did help somewhat, but it added weight. However, it did not cope with the pure physics of the Radial mast bend in strong winds. Due to its shorter length, the Radial mast has to bend much more than Standard mast to achieve adequate depowering of the sail so that the boom does not rise up when sheeting. In conditions requiring this much vang tension, the aluminium section quickly acquires a permanent bend. Over the shorter length of the Radial mast, there is much more stretching and compression of the front and back of the mast when compared to the Standard mast.

So, when Chris Caldecoat from Performcance Sailcraft Australia showed me the new composite prototype yesterday, my eyes popped and I was keen to give it a try. Over the remainder of the season, I will be putting some miles onto the new section and doing my small bit toward making the Laser Radial a much nicer boat to own and sail. The new section, made locally here in Australia by CST Composites, will not bend permanently, nor will it corrode as much. Like all carbon composite components, it will however require basic care and maintenance, as UV radiation is not the friend of epoxy compounds. Keeping it out of the sun and giving it an occasional recoating of UV inhibiting varnish will certainly not go astray and help to ensure it performs well over the years.

Many of you reading this will want to know some of the details of the new section, so here goes:
1. The upper mast fits perfectly into the new bottom section, so I didn’t need to use tape. It’s a firm fit, but not tight, and as there is no play in the joint, the top cannot twist away. At the end of the day, the two sections separated quite easily with a simple twist and pull.
2. There are 2 integral wear plates at the mast foot and at deck level. These look to be stainless steel, but I stand to be corrected as titanium is also used in these kinds of applications. The smooth plates will certainly help save both boat and mast by lowering friction.
3. Mast fittings such as the blue nylon plug at the base, stainless steel gooseneck and vang fittings are identical to those used on the current mast.
4. There are what appear to be uni-directional wrappings of carbon cloth around the top of the section and at the gooseneck and vang fitment points to give the necessary extra strength to these areas.
5. There are no inserts anywhere in the section! Well, I would have been surprised if that were the case. Looking down the tube, you only see the rivets holding the fittings. These are mostly likely to be the new Monel rivets which have been used in recent years. I notice that anti-corrosion paste has been used as a barrier between the fittings and the mast, which is good to see as carbon is known to react with metals.
6. Vital statistics! Yes, we are all keen to know what the physical differences are, so I did some comparisons with my current aluminium section.

Laser Radial Lower Section Composite vs Alu
Aluminium <-> Composite
Weight Aluminium 3.380kg <-> Composite 2.713kg
Wall Aluminium 2.00mm* <-> Composite 2.50mm
*Note that there is an insert for part of the length of the aluminium mast, so some of the section is effectively 4mm thick
7. How does it perform? I’ve only had one outing with the mast, yesterday at Belmont 16s, in about 12-15kts. Please know that I am just a Club sailor, but I do understand the dynamics of the boat quite well. These are just the first impressions and I hope to gain further insights down the track, in all wind ranges.

• The new section is around 20% lighter than the old one. A bonus weight saving has to be a good thing and considering that the intention is to resolve a long-standing bend issue, redundancy of the old mast by virtue of weight alone is not really an issue in my book as the aluminium mast has a limited lifespan anyway. I don’t know what the cost of the new mast will be, but I expect it will be significantly more expensive than the current one. (The composite top section has made the alu version redundant also) The upsides being, (1) to eliminate permanent mast bend as the primary performance impact, and (2) the cost of ownership over time being the secondary result. Of course, time will tell if this is definitely the case, but for now, I think it’s a fair call.
• I can confirm that after yesterday’s outing, that the mast has not bent permanently!
• I was told that the mast is slightly stiffer than the old one, and it does feel more dynamic and responsive. This is a characteristic of the composite top section as well. However, there is also an improvement in “useability” due to a characteristic of the alu mast which I’ll try to explain. With the alu mast, as you pull on vang and keep pulling on vang until you reach the point most of us call “max vang”, i.e. the point where the boom travels out horizontally, and not up when sheeting, it becomes increasingly harder to apply that last bit of vang, even with the 15:1 vang setup. Standard rig sailors won’t really experience this.

The new mast, even though slightly stiffer, still makes vang operation easier. In fact, it is now more similar to the Standard rig, so that is what I mean by an improvement in useability. Pulling on that last bit of vang to “max on” is significantly easier. My thoughts are that when bending the current Radial mast, you are bending two tubes, the outer tube and insert tube, so that the front of both sections of tubing are being stretched, while the backs are being compressed. With the composite section, only one tube is being stressed fore and aft as it bends, so it kind of makes sense to me that this is what is going on. If anyone has other theories, please come forth with them! I think that stronger sailors will even see fit to take a purchase out of the vang.
So that’s my initial take on the new composite Radial mast. I tried it and I liked it. In my opinion, it’s a considerable improvement over the current alu mast. Hopefully there will be more to come as the season progresses and I put more hours onto it, but I think I can safely say that Radial sailors are going to love it when it becomes official."
 

AlanD

Former ISAF Laser Measurer
#4
I wonder when people will realise that the turbo vang has not changed the amount of vang tension people use. Go back to the days of 3:1 bangs and people still could get the back main sheet block touching the deck if they wanted. The only thing that has changed is the ease or lack of technique now required to do the same thing.
 

torrid

Just sailing
#5
Makes it easier to release the vang as you approach the windward mark before you bear away. I'd think that would actually cause less strain on the spars.
 

Wavedancer

Upside down?
Staff member
#7
Interesting (?) that Performance Sailing Australia is willing to spend fairly big bucks on a product that is not approved and may not be approved for several years (if ever).
And BTW, does anybody know of a radial lower mast failing? I have seen uppers and booms fail, but no lower spars at my, decidedly less than expert, level of racing.
 

AlanD

Former ISAF Laser Measurer
#9
From my understanding, Chris Caldercoat background is in the development of carbon fibre products and he still has good contacts specialising in it. For him to develop a radial bottom section isn't that special compared to what he used to do.
 
#10
I don't know if this has anything to with the new composite top but I have broken 3 lowers in the last year. One of them was kinda old but one was only about 7 months old. I wash out my section after every sail and keep it under a cover, but I also sail in breeze 3 days a week from November to February and with a lot of vang.
 
#12
What I would like to know is how it gets an authorised for use performance sailcraft sticker and a laser trademark sticker when there has been no proposal put forward by the class association
 

LaLi

Active Member
#13
Good question, Ceebee. PSA (and LP as well) sometimes slaps the Laser logo and insignia on parts that really shouldn't have them, such as tillers, since there is no such thing as an "official" Laser tiller.

But a wholly experimental lower mast? Maybe they just think "we have the trademark and can do anything with it". Or maybe it's like Bruce Taylor says, "Radial sailors are going to love it when it becomes official." Not if but when. It would be the fourth time when we hear of a major equipment update first through an unofficial Australian source. It's becoming a pattern.

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AlanD

Former ISAF Laser Measurer
#14
Often the past equipment officially on trial has been marked so that it is legal for racing. However it has never gone into general circulation after the trial. I assume these test pieces are destroyed.
 

LaLi

Active Member
#15
Ok, fine. I still find it confusing to see those stickers on an obviously non-legal part. Also, it would be very, very nice of our class organization to inform us of these kinds of developments - I think "official" should mean "public" as well. But that's not really their style.

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