How to Protect Underwater Metals with Propspeed

Edited by Brian Vanderlaan, Last updated 12/20/2023

If you keep your boat in the water, protecting your underwater metals is a crucial aspect of boat maintenance that is often over looked or not correctly addressed. Just like the hull of your boat, your underwater metals are exposed to the same harsh environment and susceptible to marine growth and corrosion resulting in reduced performance, increased fuel cost, and the risk of invasive species spread.

Fortunately, there are effective preventative maintenance solutions available, and the most trusted and proven method is the Propspeed foul-release system.

This article will run you through what a foul-release coating is, how it protects your underwater metals keeping them free of marine growth, the preparation and application process and pro tips and tricks you need to apply and maintain Propspeed over its service life.

What Is a Foul-Release Coating?
Why Propspeed?
Planning Your Application
Preparation
Application
Maintenance
Final Thoughts

What Is a Foul-Release Coating?

Foul-release is a term used to describe the physical property of a surface (usually as a result of a coating such as Propspeed being applied) that prevents marine growth/ biofouling from adhering to it, thus releasing the fouling from the surface – foul-release. While antifoul and foul-release coatings essentially do the same thing —prevent marine growth from adhering to underwater surfaces—how they do it differs greatly.

Antifouling or zinc paints use toxic biocide as their active ingredient. Although effective on hull surfaces, these toxins can create longer-term problems in the surrounding ecosystem, and present other challenges when applied to underwater metals. Foul-release coatings, on the other hand, use physical means to reduce fouling, creating a hydrophobic surface that’s tough for marine organisms to adhere to due to its ultra-slick nature.

Marine organisms that try to settle on a foul-release–coated surface are unable to grip it tightly and while the organisms may adhere when a ship is in port, they will slide off once it gets moving. Foul-release also has the added benefit of preserving the integrity of metal surfaces since it does not leach copper out of bronze like antifouling coatings do which in turn weakens the material. This difference makes foul-release coatings ideal for propellers, running gear and other underwater metals.

Why Propspeed?

Years of Consistent Results

Propspeed is a biocide free foul-release coating best used on propellers, shafts, struts, rudders, trim tabs, keel coolers, bow and stern thrusters, pod drives, sail drives and more. The Propspeed system has been tried and tested around the world since 1999 and consistently delivers the same results: Improved boat performance, lower fuel and operational costs, and sustained investment value, all while keeping the vessel’s running gear protected against marine growth and corrosion.

With an ultra-slick topcoat, Propspeed is specially formulated to prevent marine growth from bonding to metal surfaces below the waterline. It features an exceptionally strong chemical and mechanical bond between the metal substrate, the Etching Primer and the Clear Topcoat – ensuring that the Propspeed coating strongly adheres to your running gear and protects your underwater metals for 12-24 months.

Propspeed also reduces the risk of corrosion by electrically isolating the coated metals. This limits the exchanges between the ions and gases contained in the water and on the metal. In short, Propspeed improves the corrosion protection of your underwater metals and supports the increased efficiency of your anodes.

Industry-Leading Performance

It is important to note that not all foul-release coatings are equal. Field tests have shown the adhesion strength of a barnacle on Propspeed to be around 30 to 50 kPa, much lower than tests of other products on the market, which typically came in around 125 kPa. A lower kilopascal count means much less energy or pressure is required to remove the object from the surface. Simply put: Propspeed stops barnacles from sticking better than anything else on the market!

Network of Trained Professionals

As the segment leading business, Propspeed supports their customers well beyond the transaction of selling the product. They have invested in experienced Sales and Technical Managers across the country that are on hand to support with training, product support and anything marine related.

Propspeed also has a large network of trained applicators and it's likely your local yard has been trained. These pros can handle the job for you and ensure great product performance while you do the rest of your boat maintenance. Find your closest pro using Propspeed's applicator map.

Planning Your Application

The first step in planning your Propspeed application is deciding if you will get a professional applicator at your local yard to do the application, or if you will be doing it yourself. The application process is not overly complex, but it’s important to follow the proper steps for the best results.

Figure Out How Much Propspeed You Need

Propspeed coverage calculator on a phone

Once you have decided who will be doing your application you need to identify how much product you will need for the job. Luckily Propspeed have built an online coverage calculator to make the process easy. Click the link, take 30 seconds to input your boat details and then send yourself the results, it’s that simple.

Consumables and Personal Protective Equipment (PPE)

Like any paint application, make sure you have all the consumables and proper personal safety equipment you need to complete the application before your start. The last thing you want is to realize you're missing something halfway through the application.

Check List:

Paper paint suits
Disposable gloves
Eye protection
Dust sanding mask
Dual action sander
80 grit sandpaper
Plenty of clean cotton rags or microfiber towels
Propspeed Application Kit (PSAP4KIT)

2x Disposable plastic trays
1x Roller handle
1x Propspeed roller for Etching Primer
1x Propspeed roller for Clear Coat

Planning Around Environmental Conditions

You can’t control the weather, (if we could it would always be boating weather right?), but you can chose conditions that will ensure the best application outcome. Propspeed is best applied when temperatures are in 50°–85°F range, humidity is below 85% and all application surfaces can remain dry for the duration of the application and curing process. If you don’t have access to a climate controlled shed, plan to do the job when conditions in your area are closest to these parameters.

We all know that there is a big difference between 50°–85°F, and just like anything else, this range of temperature influences the application process of Propspeed. While it is not complicated, it is important to follow the correct re-coat window based on the environmental conditions you are operating in.

Ambient temperatures influence the application of Propspeed and the set times of the metal Etching Primer and Clear Coat.

Use the chart below to understand how environmental conditions influence the re-coat window and time your re-coats accordingly.

Click on the chart to view it full size.

It is important to adhere to the above chart to ensure the best product performance. You shouldn’t rush a Propspeed job, especially when you are working in open air. If the weather does not cooperate, or if it is too cold, too hot, too humid or too windy to start a job, we recommend you wait until conditions improve. The results will be worth the wait.

Overview of Application Process

Metal Preparation

Reapplication of Propspeed

If your underwater metals are already coated with Propspeed, or if you have other coatings applied, you will need to remove all other coatings before starting the new application. The easiest and faster way to do this is with Stripspeed, a solvent-based paint stripper that has been specifically developed to remove foul-release coatings in less than 30 minutes. The thick consistency easily hangs on vertical and overhead surfaces and is easy for anyone to use. Just crack the bottle open to let some air in, shake well for 90 seconds until the consistency is thick and start using. If you chose not to use Stripspeed, old coatings can be removed using a dual-action or air-driven sander. You must wear a dust sanding mask when removing old Propspeed - inhaling any residue could be harmful.

Once you have successfully removed the previous coating, sand the metal to achieve an 80-grit profile to prepare the surface for a mechanical bond with the first coat of Etching Primer. This can be done using a dual-action sander, or by hand using 80 grit sandpaper.

Any remaining old Propspeed coating needs to be removed completely before a fresh Propspeed coating can be applied. Pressure wash the existing coating to remove marine fouling from the surface and allow sufficient time to dry. Propspeed can be removed by sanding using 80-grit sandpaper. A dual-action or air-driven sander can be used and difficult areas wet sanded by hand.

You must wear a dust sanding mask when removing old Propspeed - inhaling any residue could be harmful.

First Time Application of Propspeed

For first-time Propspeed applications, the metal surface must be abraded to an 80 grit profile to form a mechanical bond. This can be done using a dual-action sander, or by hand using 80 grit sandpaper.

With any surface coating, proper surface preparation is essential.

Application Tips

High pressure clean previously applied Propspeed
Ensure surface is thrououghly dry before sanding
Wet sand difficult areas
Ensure an 80 grit profile is achieved

Initial Clean

Once the surface has been sanded and any previous coatings are removed it’s time to clean the surface with the Propclean wipe provided.

Application Tips

All surfaces must be wiped down with Propclean
Ensure there is no residue remaining

Metal Conditioning

Apply Propprep solution liberally using the red Propprep wipe or solution. Immediately wipe the surface with a clean white cotton dry rag to ensure no residue is left.

Propprep is acidic so extra care should be taken when wiping the surface. The treated surface should be coated and primed with Propspeed as soon as possible after the Propprep solution has been wiped off with the dry rag.

You are now ready to start painting.

Application Tips

Use Propprep liberally
All surfaces must be wiped down
Regularly flipping rag side and exchanging rags will help ensure a clean and dry metal surface

Application

You can apply Propspeed yourself or have a professional applicator at your local yard handle it. The application process is not overly complex, but it’s important to follow the proper steps for the best results. If you choose to apply Propspeed yourself, the below guide will cover all steps of the application process, leaving you confident to tackle your Propspeed application.

Before you start - be prepared! Once you start this stage of the application process you need to finish it without breaks. Ensure all product is mixed and ready to go, and all the tools you’ll need are easy to access. You may need to work in sections, applying both Etching Primer Coats and the Clear Coat to one area before moving on to the next.

Etching Primer

The yellow pigment in the bottom of the Etching Primer Base can must be thoroughly mixed before adding the Etching Primer Hardener. This usually takes no more than 2 or 3 minutes.

Note: Failure to thoroughly mix the Etching Primer Base, as described above, may lead to premature hardening, inconsistencies and short life expectancy of the final coating system.

Once there are no solids left in the can, add the Etching Primer Hardener to the can and mix again. Any product not being used immediately can be re-sealed in the can and left in the shade for up to 6 hours.

Note: The cans are “short filled”, and ratio is exact in kit. It is best to mix within the can itself as you will pour only a portion of product into tray as needed, ensuring to close the lid when the can is not in use as solvents flash quickly.

For best results and to achieve the time constraints, use one of the Propspeed rollers from the Propspeed Application kit to apply the Etching Primer. A foam roller or brush can be used as a secondary option.

The Propspeed system requires 2 generous coats of Etching Primer. We recommend using a wooden stick or gloved hands to turn the prop and ensure complete coverage. Once you have applied the first coat of Etching Primer, wait until the first coat is dry and sheen of solvent is gone. Catch drips or heavy areas as soon as possible and roll out. The timing of each coat is critical to enable the required chemical bond between coats.

To test if the first coat is ready for the second coat of Etching Primer use the dry-to-touch test method: touch the wet Etching Primer with your gloved finger – if it leaves a small print on the primed surface but no Etching Primer transfers to your fingertip, then you can begin applying the next coat. The wait between coats of Etching Primer is very important and must be adhered to.

The 3-5 minute recoat timing is based on 80°F temperatures. Cooler temperatures will slow down the recoat time between the two coats of primer and warmer temperatures and windy conditions will speed up the recoat time between the two coats.

Application Tips

Use Propspeed Application kit for best results
Metals retain the temperature from the night before so consider surface temperature before applying
Ambient temperatures influence the application process
Check weather conditions beforehand
Consider using a thermometer and surface laser temperature reader to make sure conditions are ideal

Clear Coat

You need to proceed with the Clear Coat as soon as the last coat of Etching Primer is dry to touch. Allowing the Etching Primer to dry completely may result in a failure in adhesion between the Etching Primer coat and the Clear Coat.

Ensure the Clear Coat is well mixed and apply using the second Propspeed roller from the Propspeed Application kit (no foam rollers) or a brush as a secondary option. Apply a liberal coat to where it will not drip or “hang”. You have roughly 10 minutes to work with the Clear Coat before it starts to set on the surface you have applied to. If you feel you need to add more Clear Coat, or spread areas out, do so within the fluid time of the coating before it skins over to dry. Once dry, do not add any more Clear Coat as it will not stick to itself.

Any drips that harden on the edges of the propeller blades can be carefully cut off the following day with a razor blade.

Make sure the surface is completely coated with Clear Coat. Any missed areas will appear dull in luster. When you have finished coating the entire propeller with Clear Coat, give the propeller one more visual inspection to make sure there are no areas that you might have missed and to check again that there are no runs in the Clear Coat.

Propspeed requires a minimum of 8 hours to dry before launching. In cold conditions 40-60°F, we recommend at least 24 hours drying before launching. Unlike traditional bottom paints, Propspeed’s effectiveness is not adversely affected by sitting out of the water for extended periods of time in warm or cold climates.

When cleaning your hull, only use a soft cloth on the Propspeed. If the wiping cloth collects shells, remove them before proceeding with the wipe down so it doesn’t damage the Propspeed. Avoid any abrasive cleaning materials or direct high-pressure water.

Application Tips

Use Propspeed Application kit for best results
Apply much like conventional varnish
Touch up runs or sags within 5 to 10 minutes

Maintenance

Once you have protected your underwater metals with Propspeed, establishing a regular maintenance routine is crucial, especially if your boat sits in the water for extended periods. Because Propspeed is a specialized foul-release coating it requires different cleaning methods compared to regular antifouling paint.

There are two methods of removing marine growth from Propspeed depending on the type of growth that has formed

Removing Shell Growth

Use a flexible plastic resin spreader to remove shell growth
Slide along at 30° angle to break the surface tension
Dive companies using high pressure water cleaning must not use more than 1,500 PSI
Place hydro wash nozzle at a 30° angle, approx. 3 inches from the running gear and move as needed
Do not point hydro wash gun at 90° angle directly onto the Propspeed, as this may damage the coating system
Make sure to remove all shell growth before wiping the surface to avoid scratching the coating

Removing Soft Marine Growth

Microfiber cloth
Synthetic sponge
Carpet
Silicone or cotton gloves (Silicone gloves can also be used to remove shell growth)
Ensure that all shell growth is removed before wiping the surface

Never Use These Tools to Clean Propspeed

Metal scrapers
Hard nylon brushes
Any kind of abrasive pad
Power brushes

This regular maintenance will help maintain optimal performance and the longevity of the Propspeed coating.

Protecting your boat’s underwater metals is crucial for maintaining its performance and efficiency. With Propspeed, you have a reliable solution that prevents fouling, protects against corrosion, and reduces fuel consumption – all of which help to avoid costly repairs or replacements of your metal components. It’s a proactive approach to boat maintenance that pays off in the long run, allowing you to enjoy more time on the water with peace of mind.

Final Thoughts

In addition to Propspeed foul-release coating for protecting underwater metals and Stripspeed, Propspeed offers other products in their line-up such as Foulfree for transducers and Lightspeed for underwater lights. Check out Propspeed's full selection of foul-free coatings.