In mast furling masts versus classical masts. Discuss.

[AboutTime1]

I've never sailed a boat with an in mast furling system. I know nothing about them. I see them on a lot of newer boats these days. Are they good or bad ? Avoid them or seek them ?


Thanks

[Cheechako]

Uh oh! This is gonna be like talking anchors!

Pro: In mast is great for putting the boat away quickly. No sail cover, no ties.

Con: Most in mast mains drastically reduce the sail power, where it counts... in the leech.

I've had both, and I've sailed a few different examples of in mast furling.

For a standard mainsail vs an in mast mainsail, I would say I can reef the standard sail reliably and more quickly with less trouble than an in mast main on average. However, you need to go to the mast to do it. This assumes I'm on a boat that I own and I am used to .

In light air and flat water possibly a bit quicker with in mast.

[GreenWave]

Just to add some from my experience to Cheechako... in-mast is NOT for racers. It is for cruising and ease of use. It is easier if you are single handing and have lines to cockpit and electric winch. It is easier to set a reef initially (and has unlimited settings), but not as easy to take it out.

[Dockhead]

This is a polarizing issue, with some people hating them -- mostly those who have never had them. Others loving them. You'll have to make up your own mind.


I have had both types and neither love nor hate in-mast furling, so maybe I can give you a neutral answer. Like everything on boats, this system has pros and cons:


Pros:
1. Furl and unfurl and reef and unreef from the cockpit without altering course. Big safety advantage.
2. No need to flake and cover the sail after use. Big labor saving, especially on a larger boat.
3. Ideal storage of the sail rolled up and protected inside the mast -- sail lasts longer.
4. Infinite and effortless reefing -- so much easier to always have the right amount of sail area out. This can have considerable performance benefits. Sailors with in-mast furling are often able to avoid reefing their headsails at all -- which has great performance benefits.


Downsides:
1. Less power because of less roach and less shape (in-mast furling sails cut flatter).
2. No tolerance for bagging out of the sail -- baggy sail will jam. So either replace sail frequently or use laminate.

3. More weight aloft because the sail and foil inside the mast.
4. No mast bend as a sail control -- if you bend the mast, you'll jam the foil.
5. Hydraulic and electric in-mast furlers can be troublesome.
6. More maintenance even with drum-type furlers.
7. Requires more knowledge and skill to operate than normal slab reefing.



So what's best? Only you can decide. In my opinion, in-mast furling makes a lot of sense for sailing in higher latitudes where there is usually a lot of wind and where you are reefing a lot, and for sailing offshore with frequent bad weather. Especially with larger boats.



For coastal sailing and sailing in mild latitudes, and especially with smaller boats, the advantages of in-mast furling are much less beneficial, and you'll miss the performance hit. I would choose normal slab reefing for this case, with a large roach in the mainsail. Ditto if you do much racing (although we do race with in-mast furling and with considerable success).



If you do go with in-mast furling, some tips:


1. Learn how to use and maintain the system. If you operate improperly or allow to get out of condition, you have risk of jams. Correctly operated and maintained, the risk of a jam is vanishingly small.



2. Keep up with the maintenance. Keep the swivels and gears lubricated and clean, keep the foil correctly tensioned.


3. Use a good mainsail. Laminate is ideal. In-mast furling and laminate sails go together like cookies and cream. Laminates are thinner, lighter, and more flexible, and in-mast furling works like a dream with them.


4. Use SailKote or equivalent on the mainsail.


5. Use a mainsail with vertical battens and straight luff or slight roach -- not the hollow leech like many in-mast furling boats are delivered with. This makes a huge difference in performance.



Good luck!

[S/V Illusion]

With few exceptions, owners of boats I know with furling mains have experienced problems with them not as a result of their own doing. As for sailing characteristics , our boat was originally equipped with a furling mast. After sailing her for two years, we trashed the mast furler and replace it with a traditional full roach main on a boom furler and carbon mast. Huge improvement.

[Dockhead]

Originally Posted by GreenWave

Just to add some from my experience to Cheechako... in-mast is NOT for racers. It is for cruising and ease of use. It is easier if you are single handing and have lines to cockpit and electric winch. It is easier to set a reef initially (and has unlimited settings), but not as easy to take it out.

These are good comments, all true.


Just to note, however, that racing with in-mast furling is not necessarily a hopeless endeavor. If you have a good quality laminate sail with some roach in it, and vertical battens, you are getting close to boats with normal sails, and then you have the performance advantage of more control of sail area.



In very light wind you will never be quite competitive to a boat with a normal mainsail (all other things being equal), but in strong wind you might actually have an advantage. So for long distance ocean racing (what we do), in-mast furling is not all that bad, even if it's not quite ideal.


Racing in light wind we aggressively use an A2 whenever possible, which makes the mainsail irrelevant.

[AboutTime1]

Originally Posted by S/V Illusion

With few exceptions, owners of boats I know with furling mains have experienced problems with them not as a result of their own doing. As for sailing characteristics , our boat was originally equipped with a furling mast. After sailing her for two years, we trashed the mast furler and replace it with a traditional full roach main on a boom furler and carbon mast. Huge improvement.

Wow. What boat did you do this on ?

[AboutTime1]

Thanks for the replies !

[Joh.Ghurt]

Originally Posted by AboutTime1

I see them on a lot of newer boats these days. Are they good or bad ? Avoid them or seek them ?

If you see a solution often and you haven't experience with it, assume that all those boat-builders and buyers aren't idiots and there must be enough benefits to compensate for potential drawbacks. Thus the answers you seek are:

Good enough for most cruisers.
Don't avoid them.

Done.

This line of reasoning also works for fin-keels, bolt-on keels, davits, cloth dodgers, dacron sails and any other controversial topics where the internet experts love to call each other names while the rest of us just are out sailing.

[donradcliffe]

Unless you get a rating credit for a hollow roach, forget racing.

A couple more cons:

They can howl in a crosswind.
MTBF is less than 3000 miles, and impossible to fix at sea.

[thinwater]

Possibly a dumb question.


Why did rolling around the boom go out of fashion? I suppose in favor of system where all lines can be led to the cockpit.

• Impractical on taller masts.
• Still have to cover it.
• Still have to attach downhaul and outhaul after reefing (failing to do the later will tear a sail).
• Easy, but can't be managed from the cockpit. Can hoist a previously reefed sail from the cockpit.
• No bunt of sail to tie-up.
• Easy on laminate sails because there is no folding or tight rolls.
• No lazy jacks.

I have a roller boom on my F-24, and it is one of its most functional features. I do have to go to the mast, which I don't mind, I and I do have to attached the outhaul, but I can reliably make my main disappear in a rising wind, which is what I want.

[rslifkin]

Originally Posted by thinwater

Possibly a dumb question.


Why did rolling around the boom go out of fashion? I suppose in favor of system where all lines can be led to the cockpit.

• Impractical on taller masts.
• Still have to cover it.
• Still have to attach downhaul and outhaul after reefing (failing to do the later will tear a sail).
• Easy, but can't be managed from the cockpit. Can hoist a previously reefed sail from the cockpit.
• No bunt of sail to tie-up.
• Easy on laminate sails because there is no folding or tight rolls.
• No lazy jacks.

I have a roller boom on my F-24, and it is one of its most functional features. I do have to go to the mast, which I don't mind, I and I do have to attached the outhaul, but I can reliably make my main disappear in a rising wind, which is what I want.

Along those lines, roller furling booms do exist, although they're not nearly as common as roller furling masts. They basically work like an in-mast furler, but they furl into the boom instead. Which means you have more options for battens and a sail with more roach, but you end up with a big, heavy, chunky boom in exchange. And they're more expensive than in mast furling.



I think one of the issues with the roller furling booms like you're describing is that if it's not meant to hold the sail wrapped for storage, you're forced to un-reef before you can drop the sail.

[Dockhead]

Originally Posted by donradcliffe

Unless you get a rating credit for a hollow roach, forget racing.

A couple more cons:

They can howl in a crosswind.
MTBF is less than 3000 miles, and impossible to fix at sea.

Little out of date -- most furling mains have some roach nowadays, which is straightforward with vertical battens. See for example:



That one even has a carbon furling mast. Very good shape and very good performance; that's the new HR50 https://www.hallberg-rassy.com/yacht...lberg-rassy-50

As to "MTBF 3000 miles" -- not with anyone I know. I've done about 50,000 miles in mine and have had a grand total of three jams -- one really bad one the first year when I didn't know what I was doing, and thereafter two minor jams easily cleared from the cockpit in 5-10 minutes, and both operator error. That's pretty typical once you know how to use the system, assuming you start out with a good system like Selden (some older systems did not work well). This is not greater MTBF than what I experienced with slab reefing systems.

The manual furling systems with endless line operation are pretty bulletproof. Jamming is practically non-existent with laminate sails and reasonable operator competence. Hydraulic and electric furling systems are more troublesome in my experience.

I'm not selling in-mast furling -- and I would prefer slab reefing for many use cases. But in-mast furling does not suck at all provided you maintain and use it properly.

More shots of modern in-mast furling mains:





A lot of people's prejudices about in-mast furling are based on experiences from the 90's with older systems and baggy dacron sails without battens and with hollow leech. Modern systems used with laminate sails and vertical battens are just totally different, both in terms of performance, and also in reliability.

[TrentePieds]

AboutTime1 said: "I've never sailed a boat with an in mast furling system. I know nothing about them. I see them on a lot of newer boats these days. Are they good or bad ? Avoid them or seek them ?"

It rather depends on where you sail and how you sail. For the sort of summer cruising most people in the Salish Sea do, there is absolutely no reason to accept the complications, annoyances, detractions from performance and addition expense "in mast" furling brings with it. Particularly not in smallish boats, say under 10 tons.

That is not to say for some people doing more "sophisticated" sailing in different waters a case cannot be made for "in mast" furling. Though not by me ;-0)!

I might be misjudging your level of expertise, and if so, forgive me. If you are a cruising man of modest ambitions sailing a modest boat in modest waters (as I am), you will find that slugs running in a cove or, better still, slides running on a track will enable you to do every evolution of reefing and furling you will ever need with far greater ease than you can with "in mast" furling. Remember that furling and reefing are two different breeds of cat!

TrentePieds

[grantmc]

This topic is great sailboat topic, and there will never be a resolution. Isn't sailing wonderful.

I've sailed as crew on a Hallberg-Rassy 42 with in mast furling. No sail battens. The system included an electric winch and worked very well to unfurl. But when furling in the sail tended to crease and as a result it could cause thick spots. So we had to be a little careful, furl in a little, see it crease so unfurl, pull down manually on the sail and repeat. But overall it was great. A really big mainsail so the simplcity of mostly remaining in the cockpit to reef down was brilliant.

In respect to boom reefing, My first yacht had boom reefing. But it wasn't in-boom. The boom itself rotated by winding a little handle at the gooseneck. So you just rolled the boom and it pulled down and auto wrapped the sail around it self. And the vang, downhaul or whatever you prefer to call it was mounted near the end of the boom. It was a great system and quite fail safe. It's a shame they've gone out of fashion, because it purely is fashion, nothing else. And yes the main on that little yacht had horizontal battens. Admittedly a little shape was lost on the sail when reefed, it became a tad baggy, so we lost like maybe .2 of a knot.