Round “sail slugs” VS flat “sail slides”

[PaulDaniel]

My mast can accept either 5/16 inch round “sail slugs” or 5/8 inch flat “sail slides”. I’ve read that in theory, slugs have less friction, but that in practice, slides are better because they reduce binding. I read that in particular, undersized slugs can be especially prone to binding. Has anyone used both who can tell me their experience?


These are the particular ones I was considering:

SLUGS

Allslip Round Slug 5/16"

Allslip Round Slug 5/16 is a low friction nylon plastic alloy slug used to make lowering sails easier. This sail slug has excellent strength and is long in length to reduce the possibility of jamming. Ideal for full batten applications.

www.sailrite.com

SLIDES

Allslip Flat Internal Track Slide 5/8" (Nylon)

Allslip Flat Slide 5/8 is a low friction nylon plastic alloy slide used to make lowering sails easier.

www.sailrite.com

 

[Project_Mayhem]

Very interested in hearing feedback on this. Regardless, a proper cleaning and lube of the slugs/slides and track makes a HUGE difference. Even bigger than a proper sheave.

 

[dmax]

I have had both and can't say I noticed a difference. I went with slugs on my new main.

 

[Tally Ho]

I can’t answer your question, but for thought….

The best thing I have seen is the Tides Marine strong track. It includes a HDPE track that slides up into your existing mast groove, and special heavy duty stainless slides. I got it as an upgrade when I bought a new full-batten main sail a few years ago. The full-battens add a bit of friction, so the Strong Track is recommended to counter that. I am very impressed with the set up. Not sure that you could easily retrofit an existing sail with the new slides (but maybe). I installed the track myself.

My previous boat had a Harkin Batt-Car system (it was a Hunter 280, and also had full battens). That also involved a track and “cars” at least on the battens.

Greg

 

[PaulDaniel]

An external slide track would be awesome! I don't think I can justify the cost/benefit ratio for myself though. I do have a full battened main.

 

[stickinthemud57]

Very interested in hearing feedback on this. Regardless, a proper cleaning and lube of the slugs/slides and track makes a HUGE difference. Even bigger than a proper sheave.

I use slugs and have not had any troubles. I do apply Sailkote in the slug track every so often. Yep. Huge difference.

 

[Project_Mayhem]

I use slugs and have not had any troubles. I do apply Sailkote in the slug track every so often. Yep. Huge difference.

After a rigorous cleaning one year, I maintained the bare aluminum mast track the following years with a magic eraser and WD40 Dry PTFE lube. I actually like this better than SailKote. The eraser makes VERY fast work of it if your mast is down.

I am curious if the slugs pick up less dirt. The edges of the slides scrape the dirt off the track. Not sure if that's good or bad

 

[PaulDaniel]

This is the only source I was able to find saying that flat slides are better… Here is this from Quantum Sails:

“The type of slide used has an impact on how well the sail goes up and down. Flat slides (the most common type on newer boats) are best. They cannot get twisted out of line. Round slugs are the worst because the twisting forces will often cause them to lock up in the groove, particularly if they are smaller in diameter. External claw-type bronze or nickel-plated steel slides (found on older masts) are a problem too, due to the inherent friction of the claw arrangement, and the joints between the sections of track. On larger sails, a separate, external luff track (like Tides Marine, Antal, Harken, etc.) becomes necessary to ensure easy operation”

URL:

The Lowdown on Battens

Battens are an important part of the sail structure, but with many different options and different use cases, it can get confusing. Here is the lowdow...

www.quantumsails.com

 

[dmax]

Never had a slug lock up in a the groove so saying it happens often is a little much - countless main raisings. On my current boat, the slug has wheels that prevent the slug from twisting:

 

[PaulDaniel]

Those slugs look incredible! Where did you source them? I can’t seem to find them online.

 

[dmax]

They came on the main when I bought the boat and were in excellent shape so I had them put on my new main, didn't have to buy them. The aft part of my mast is flat so the wheels have a good surface to ride on, they don't work on all masts I'm guessing. Here's one I found though the price is in euros, looks like they are called "pressure absorbing roller slides": Universal Pressure Absorbing Slide | Low Friction Mast Slide

 

[PaulDaniel]

Thanks. I’m sure they are worth. I think I’m going to buy the Ronstan Allslip flat sides and see how they work.

Just some thought about the physics:

- According to the Coulomb friction model, surface area doesn’t factor into friction. Higher pressure over a smaller contact area is equal to lower pressure over a greater contact area. What IS factored into friction is the friction coefficient (a material property) and force. Of course if dirt and grime is in the contact area then that will effect the friction coefficient. Therefore, any superiority between slugs vs slides would be related to binding.
- The way that the slides are loaded while raising the main depends on if you have a battened mainsail and whether you are motoring directly into the wind (basically no side loading) or on a close reach with the mainsail flogging (moderate side loading).
- If you meticulously clean and lubricate your mast track, you can probably use any kind of slug or slide. Even still, choosing one kind of slug or another based on features might give you a tiny or even moderate performance gain. If you want the ultimate performance, that would probably entail something like the Tides Marine strong track or similar. But if you need to stick with regular slugs for budget reasons, you could still probably see some benefit by choosing quality slugs (for example, a slug that is glass reinforced plastic with impregnated PTFE rather than a basic nylon slug).

 

[Project_Mayhem]

If you meticulously clean and lubricate your mast track, you can probably use any kind of slug or slide. Even still, choosing one kind of slug or another based on features might give you a tiny or even moderate performance gain. If you want the ultimate performance, that would probably entail something like the Tides Marine strong track or similar. But if you need to stick with regular slugs for budget reasons, you could still probably see some benefit by choosing quality slugs (for example, a slug that is glass reinforced plastic with impregnated PTFE rather than a basic nylon slug).

 

[Ward H]

I followed @Tally Ho thread on his upgrades and did the same when I was having a new main built.
Very happy with the system.