Product Update October 2019 Issue

Gear of the Year Roundup

Practical Sailor turns focus on small boats, seamanship, and DIY projects.

The bulk of the past year’s testing focused on maintenance products, safety essentials, and do-it-yourself substitutes for higher priced marine gear. This was a deliberate move as the staff here at Practical Sailor tries to buck the trend toward high-priced, budget-busting marine-grade gear that is out of reach of many sailors.

3M Cubitron Sandpaper

With a bottom-sanding job on the horizon, we began a search for the best paper for the job. Although you wouldn’t think something as pedestrian is sandpaper could vary so much in quality, it does. The more premium products developed for machine sanding wear so much longer and cut so much faster that it is false economy to use inexpensive garnet paper.

Sanding bottom paint is about bulk removal, avoiding paper clogging, and capturing as much dust as possible. We’ve tested many different kinds of sand paper over the years (see “Hand Abrasives Roundup,” July 2006, and “Carborundum’s Premier Red Shines for the Price,” April 15, 2001). Since then, we’ve settled on a favorite, but there are many quality products out there just crying out for comparison.

The test focused on 80-grit because it is the common recommendation for bottom prep. If you are stripping the paint down to the hull, move down to 60 or even 36 grit, but beware that such coarse abrasive can cut through gelcoat and barrier coat quick as a wish. The 80-grit paper is slower and far more forgiving. We focused on popular abrasive papers, available through chandleries and home improvement centers, including products by 3M, Diablo, and Gator. We also tested a sanding sponge and two grades of Scotch Brite pads by 3M.

We tested removal rate and loading by sanding roughly 2- by 5-foot sections for exactly two minutes using a ¼-sheet DeWalt orbital sander attached via a short smooth-bore hose to a vacuum cleaner with a high efficiency filter. The amount of dust recovered was weighed on a precision digital laboratory scale and the speed of removal was visually observed. Fouling of the sand paper was visually graded and wear rate was judged by tactile change in roughness. We also used several of the more effective papers for sanding larger areas.

Our favorite is the purple 3M Cubitron II, which is available everywhere, cuts fast, and is inexpensive enough to replace regularly. Better papers have a non-slip backing; less slipping against the pad means more sanding action. We think this accounts for some of the higher removal rate of 3M’s Cubitron II paper. Cubitron II adheres lightly to the pad, something like a Post-it Note (also a 3M product). Hook-and-loop attachment methods, found on round sanders, provide the same benefit. It was our best choice for heavy removal.

The 3M sanding sponge is handy for finish sanding on wood and between coats of varnish or enamel. It performs much like the Cubitron II sandpaper and is exceptionally long lasting. If it loads up, it can often be rinsed clean. However, we didn’t find it very useful for bottom paint.

The Scotch Brite pads are much like steel wool, but with better handling and far less shedding. The green pads (the color identifies the grit) are perfect for reactivating a hard paint that has been dried out for too long without removing too much paint.

Do not use a green Scotch Brite for in-water cleaning of antifouling paint—the paint softens in the water and the pad will take the paint right off, diminishing paint life and putting excessive biocide (usually copper) into the environment (see “Cleaning Your Hull,” April 2018). The maroon pads are suitable for a quick scratch sanding, but they won’t remove bulk paint or level out chipped spots. They aren’t a sandpaper replacement.

3M 4000 UV and Sika 291

We expect a lot from sealants. They must withstand UV, salt and cleaning chemicals, bond to everything, flex to absorb mechanical and thermal strains, be strong but removable when equipment needs serviced, and stay white.

In PS “Marine Sealant Adhesion Tests “(December 2016) we tested the shear strength of many caulks on many materials and delivered a few tentative recommendations. Three years later, we followed up with field observations focusing on mildew.

We tested a field of leading sealants including 3M 5200, 3M 4200 Fast Cure, 3M 4000 UV, Sika 291, Sika 295, Loctite PL S-40, Loctite PL Marine, Boat Life Caulk, Boat Life Seal, and Sudbury Elastomeric Sealant. One surprise was the significant difference in dirt attraction. At the 6-month and 1-year checks we saw significant spots that looked like mildew growth, but when wiped with a cloth and plain water, they all came clean. And yet, there were differences related to surface texture. Boat Life Seal, which contains silicone, repels dirt, while the polyurethane sealants attracted dirt. The downside of silicone is that it can inhibit bonding in subsequent projects (see PS January 2017).

After three years, none of the samples would come clean with plain water, so we scrubbed them all with a typical deck cleaner in the hope of revealing differences. In fact, with the exception of Loctite PL S40, they all came clean. Boatlife Seal and Sika 291 were slightly easier to clean.

Good flexibility, good adhesion, and superior weather resistance made 3M 4000 UV our Best Choice. Ease of removal remains a question, since we have not tested removers on polyethers (see “PS Tests Adhesive Removers,” January 2017).

Sika 291 performed a lot like 3M 4200 Fast Cure, but with more consistent bonding on a wider variety of materials. It came clean easier than most and retained flexibility. This was our other Best Choice for most applications.

We like Sika 291 and 3M 4000 UV for good bonding, flexibility, and weather resistance. Boatlife Seal is impressive if you don’t mind silicone, but we’d avoid Boatlife Life Caulk. 3M 5200 is remains our choice for permanent bonding and below-the-waterline work.

Rivets vs. Screws in Spars

Hardware upgrades to the spars of one of our test boats led us into the world of fasteners for small boats, and ultimately, to a debate over screws vs. rivets.

 

First, we had to settle the fine thread vs. course thread argument with regards to fasteners. The finer thread permits closer adjustment where gasket compression is critical. On the other hand, coarse threads resist stripping better, a critical advantage in thin materials such as small-boat spars. The larger threads are more fatigue resistant, and cross-threading is less likely, both important in soft materials like aluminum. Finally, coarse threads better allow for galvanized coatings and anti-seize compounds.

In the end, our testers concluded that coarse threads are the first for choice for aluminum spars and most nearly all stainless bolt applications. Fine threads are the first choice for high-strength bolts on cylinder heads that have specified torques.

As for the preference of screws or rivets, we like threaded fasteners wherever the spar material is 1/8-inch or greater. Screws are removable, draw-up range is good and strength is predictable.

However, when the material gets thin and soft, threads become weak. So a rivet is often preferred when the metal is less than ?-inch thick. This includes masts and booms on most boats up to 30 feet. Rivets are very well-proven in these applications.

The most important consideration when choosing fasteners is the nature of the load on the new hardware. If possible, the load should be entirely in shear, and the load should be shared by enough fasteners to insure the working load is not exceeded. When an outward pull is unavoidable, it must be considered that the whole load may be carried by a lone fastener.

For related topic, see “Anti-seize coatings for spars,” PS July 2018

Clear Plastic & Treatments

There are two classes of clear vinyl protectants: spray cleaners that are applied every few weeks and creams or pastes applied quarterly. The sprays focus on cleaning and shine, and all claim some UV protection. The creams and pastes clean more completely, provide a more substantial film and require more effort. 

For this test, we observed the aging of known and unknown vinyl samples that had been restored using either one of the packaged restoration kits or one of the protectants tested in this review.

Protectants reduce internal hazing due to high humidity, particularly in restored and older, non-coated vinyls. The protectants reduce dirt buildup, bead water, and prevent hazing in humid weather. Star brite View Guard proved particularly effective at all three tasks.

All of the cleaner/protectants produced an acceptable shine, with Armada 210 rating best as a cleaner. Among the cream and wax protectants, Imar Protectant led the field, producing a smoother feel and longer-lasting water repellency. Star brite View Guard excelled as a cleaner and noticeably improved visibility in rainy weather by sheeting the water. Covers provide the very best protection, supplemented by occasional use of an effective wax or spray protectant. Covers are also the only effective preventative for reflected UV damage.

With care and proper protection, a high-quality, clear plastic window that is kept covered and carefully maintained can last 20 years. By comparison, plastic that is renewed and polished with fine compound at frequent intervals is unlikely make it past five.

Any abrasive restoration should be used only as a last resort. Some things are better left alone.

PIC 1
Clockwise from top left: Star brite View Guard excels as a spray cleaner protectant; rivets prove their mettle in sheer testing; Sikaflex 291 was rated as a top all around adhesive sealant; 3M Cubitron II bears down on boat bottom.

O’sea & strataglass

There are several manufacturers and two classes of vinyl window materials (glazing). Our testing focused on the premium products, O’Sea and Strataglass; and two less expensive, uncoated products Regalite and Crystal Clear.

Coated vinyl (O’Sea and Strataglass) substantially outperformed uncoated vinyl (Regalite and Crystal Clear) in humid conditions, and are worth the extra expense. One drawback is that they are less flexible than uncoated vinyl. Flexibility doesn’t matter for fixed windows, but we recommend either O’Sea or uncoated products for windows that must be rolled-up in use, using either 20 or 30 mil thickness. Save the 40 mil products and Strataglass for windows that never move.

Covers are very effective at preserving clear vinyl, but you should keep them from flapping against the vinyl. Micro-scratches from excessive cleaning are a common cause of blurry clear plastic, so whatever the material keep cleaning to a minimum.

The window materials were compared in more detail in a previous report (see PS January 2014 “How do Different Vinyl Types Compare?”).

Star brite View Guard

All of the cleaner/protectants that we tested helped preserve clarity of clear plastic by protecting against moisture and dirt. (Claims of protection against UV exposure could not be confirmed by our test methods.) After comparing several sprays and cream polishes, two products stood out.

The budget-priced Star Brite View Guard was the easiest to use of the group. This product stood out in its ability to sheet the water off, improving wet weather visibility. And if you follow the manufacturer’s suggestions, it polishes to a beautiful shine.

With cream polishes, it’s important to follow the instructions. Some makers tell us to the let the product dry to a haze before buffing; others are to be wiped off immediately.

Imar Protective Polish

Imar Strataglass Protective Polish cream-type cleaner wax is the only polish endorsed by Strataglass for use during the warranty period. It easily produced a mirror gloss and was among the most effective products for restoring gloss to vinyl. It is expensive compared to other products, but you use it only used a few times each year.

Rust protection bags

Looking for ways to protect their tools, several readers suggested we look at Zerust, Coretec, and similar Ziploc-style VCI (vapor-phase corrosion inhibitor) bags that control humidity and oxygen flow, and are impregnated with anticorrosion chemicals.

These bags are available in sizes ranging from a snack-bag size to one large enough for a laptop—or even an outboard engine! We tested 6- by 9-inch bags.

To test, we polished 1- by 2-inch sample coupons (tabs) of representative metals, assembled into galvanic parings: brass to aluminum, solder to copper, and steel to brass. We placed these samples, along with USB flash drives and a compact disk, inside each of the following: a storage bags, a common Ziploc bag (with Dry Top silica), and a Ziploc bag with no protection at all. We left them in a footlocker-sized humid chamber for one year.

At one month, the open-bag control was showing heavy condensation and the flash drive had failed, and within two months the aluminum sample was showing visible corrosion.

At six months, all of the bags had slight internal condensation, except for the Dry Top bag. The silica gel in the Dry Top canister had changed color, so we regenerated it in the microwave and reinserted into the bag. The flash drives had failed in all but the Dry Top bag.

At the end of one year, all but the Dry Top bag had considerable internal condensation. The flash drive in the Dry Top bag was still functional. All of the CDs were intact.

The VCI bags did outperform plain freezer bags, but the difference was small. We recommend using Ziploc bags for delicate parts, and double-bagging critical items with silica gel capsules of one sort or another. The anti-corrosion bags are overpriced for something with marginal benefit for sailors. If you want something for your toolbox, we’d opt for re-usable silica gel boxes over emitters. 

PIC 2
The well-balanced and sensitive Little Hawk MKII from Schaefer topped the other deck-level wind vanes in our comparison.

SCHAEFER MARINE LITTLE HAWK MK II

Single-sail boats, such as Lasers and Optimus dinghies often clamp wind indicators on the forward side of the mast (see Practical Sailor, January 2018, “Top Notch Wind Indicators”). Without a jib to interfere with windflow or to luff at every wind shift (thus serving as a wind vane), they give a real-time estimate of wind direction.

The primary function of these bow vanes is not fine-tuning or fine steering adjustments. These are made based on sail-mounted telltales and the look of the sails themselves. We’ve tried several different brands and models of deck level vanes and found something of merit in each of them.

Easy to mount, extremely sensitive and highly visible, the Little Hawk MK II might look fragile. But we haven’t been able to break one in two seasons. It remains the most sensitive after a year of blasting through waves, even more sensitive than our masthead fly.

If money is your biggest issue, you can always use what we use, a brightly colored fly made out of yarn (see PS March 2019).

Comments (4)

I used to own a plastics fabricating business and the best sanding discs I have ever used are Norzone which are resin bonded and last at least five times longer than any other type. Their cost was 50% more than others but ordering in large quantities brought the price down dramatically. I believe they are a Norton Abrasives products. I also bought them for Makita baby sanders (1-1/8"x 21") and had excellent results.

Posted by: gimpy666 | October 13, 2019 8:19 PM    Report this comment

Another point for fine vs. course threads consideration - fine thread fasteners have greater strength when the dimensions are correct and for when the female thread material is the same strength as the screw, but for hand tapped holes, wobble of the drill or tap and lack of perpendicularity will result in reduced strength of the female thread. The same amount of mis-machining will result in a greater strength reduction in fine threads. It is not uncommon in "difficult" situations to find that fine threads don't even support normal installation torque. When you also consider that the shear strength the aluminum is well below that of the SS screw an that the aluminum may be less than the 1 1/2 d normal thread engagement, course threads are better.

Posted by: Captain Ed-79 | October 13, 2019 1:24 PM    Report this comment

As for the tools, I have used the zerust tool chest liners and a couple of silica gel packs, but the key for me is wiping down the tools and the Pelican box - nothing like keeping new condensation out. I went to the Pelican after having one on our - very wet J80 race boat - I hadn't needed my tool kit in over a year and pulled it out and every tool was perfect.

Posted by: Relentless | October 13, 2019 10:30 AM    Report this comment

"As for the preference of screws or rivets, we like threaded fasteners wherever the spar material is ?-inch or greater. "
Uh, OK... and ?-inch equals ???? And does that imply proper rivets are preferred when the spar material is less than ?-inch ???

Posted by: Port Noir's Complaint | September 30, 2019 5:02 PM    Report this comment

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