Thrusters - bottom paint?

[rocklobster]

Taking delivery on New C28 next week

Should I put bottom paint on the stern and bow thrusters?

Specifically:
Impellers?
Tunnel on bow?
Outside of stern thruster housing?
Ablative?

I boat in Connecticut

Thanks!


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[trailertrawlerkismet]

I think it’s a good idea to apply bottom paint to the thrusters. With that in mind I’ve always taken the propellers off to paint them. When painting inside the thruster housing one needs to be careful to NOT get bottom paint on the propeller shaft. The bottom paint helps keep the area free of barnacles n growth which helps keep the thrusters operational.

Jim F

 

[ixlr8]

The thruster on my RT-27OB looks to have been bottom painted at the factory, none of the rest of the boat was. It was the only area on my boat that didn't have growth after 6 weeks in the water. But if you are doing it, it would be easiest/best to remove the props and paint them separately. There are many different types of bottom paints and one factor is; will the boat stay in the water, or will it be removed occasionally. There are some bottom paints that must remain wet to be effective. Others are okay to be allowed to dry out. My guess, in Connecticut, you are going to pull the boat for the winter in which case you should not use a paint that must stay wet to work. There are lots of good products out there, prep work before painting is the key to a quality job. If you ask 10 people what is the best product to use... you will get 15 answers. Ask around your marina to see what others in your area are using. What works in CT, may not work in FL or CA and vise versa. The other question, how environmentally conscious are you? There are some questions about using bottom paint with copper as the active ingredient which can cause issues when it gets in the waters. There are now some "environmentally friendly" bottom paints that cost more but are suppose to be better for the marine environment.

 

[BB marine]

I am a believer, if its under water it is painted. If it is metal it needs to have a metal etching primer, primed with a barrier coat and then application of antifouling paint. The thruster housing needs to be primed with a epoxy barrier coat to get a good adhesion, then coated with antifouling paint. ( AS per Side Thruster painting directions) If this is not done the anti-fouling may not adhere to the housing surface. As Jim stated removal of the thruster props should be done for a proper application. When installing the props back on the shaft apply a small amount of anticorrosion grease on the prop shaft to ease removal in the future.

SIDE POWER THRUSTERS
Bronze Thruster Unit and Aluminum Thruster Tube (if applicable)
Remove all grease and other contamination by wiping down with Interlux #355 Solvent
Sand both thruster unit and aluminum tube with medium to coarse grit emery paper to bright metal, to remove all oxidation and create an anchor pattern for subsequent coats of paint.
Apply one thin coat of Interlux Viny-Lux Primewash #353/354 that has been thinned 25% with Interlux #355 Solvent. Allow to dry for one hour but no more than 24 hours before application of Interlux Interprotect 2000/2001.
Apply 4 to 5 “heavy coats” of Interlux Interprotect 2000/2001 to both thruster unit and aluminum tube to achieve a minimum of 10 mils dry film thickness. Care should be taken to stripe all edges (apply extra paint to sharp edges). Follow dry times on label to re-coat.
Apply 2- 3 coats of Interlux TriLux 33 as soon as final coat of Interprotect is “thumbprint tacky”. Follow dry times on label to recoat Trilux 33 .
Nylon Composite Propeller and Fiberglass Thruster Tube (if Applicable)
Remove all mold release wax and other contamination by wiping down both nylon composite propeller and fiberglass thruster tube (if applicable) with Interlux #202 Solvent Wash using the two wipe method.
Sand both units with 80 grit paper to create an anchor pattern for subsequent coats of paint.
Apply 1 heavy coats of Interlux Interprotect 2000/2001 to both the propeller and fiberglass tube.
Apply 2-3 coats of Interlux TriLux 33 as soon as final coat of Interprotect is “thumbprint tacky”. Follow dry times
on label to recoat Trilux 33.
Note: Coatings should not be applied to zinc anode mounting surfaces or prop shaft.
Note: When fairing the thruster unit into a fiberglass hull. 1st sand fiberglass with 60 grit paper, wipe down and apply Interlux #YAV867 Interfill Epoxy Filler or #YAV135 Watertite . Sand fairing compound to fair in tube and apply a minimum of 10 mils dry film thickness (4 to 5 coats) of Interlux 2000/2001. Coat antifoulant when the last coat of Interprotect is thumb print tacky using the same antifoulant as on the rest of the hull.
Note: Contact INTERLUX YACHT FINISHES for fairing recommendation to fair aluminum thruster tube into aluminum vessels at 1-800-468-7589.
YACHT FINISHES
2270 Morris Avenue Union, NJ 07083 Tech. Service: 800-468-7589 done to paint properly.

Pettit has products equal to interlude and the same application can be done with Pettit products. As per Imtra (Side Power) Service Technician.

Notice the instructions for the thruster gear housing, This is tedious to do but will help prevent the housing from corrosion and help increase the anodes life. This same application can be done on the Keel shoe, engine, generator and air unit thru hulls, the rudder and trim tabs.

I worked in New England waters ( marine technician) for four years, Narragansett Bay and Buzzard bay waters( Awesome area for boating). If it didn't have some type of antifouling application on it and it was under water, after a season it had fouling on it. The stern drives were the worst, outboard transom brackets-(portion under the water), trim tabs, rudders, struts, and thru hulls all had fouling too.

 

[baz]

My response to this is...

Impellers? NO The props are composite and over the years I've seen no barnacles or crud growth... painting them will alter their surface and thrust capabilities to some degree.
Tunnel on bow? YES ... keeping the tunnels clear is a good idea.
Outside of stern thruster housing? YES ... but not really necessary... will simply make outer surface more pleasing to view.
Ablative? Your choice

I have contracted a diver service and they will periodically lightly brush underwater items such as thruster props, thruster's tunnels, trim tab surfaces, raw water pickup grate and check my hull bottom paint to ensure it's still healthy and doing its job. Replacing thruster anodes at ~50% wear if they are SidePower brand is absolutely essential otherwise significant damage to the thruster assembly will occur and be expensive to repair/replace.

I would also suggest if boat in water 100% of the time then maybe once a year or once every two years have the boat hauled out and when on the slings have the hull power washed carefully at low pressure. This will also allow you to see how healthy the bottom paint is and if some starts to slough off its time to repaint.

 

[Brian B]

I boat primarily in RI. From my experience if you do not paint the thruster props they will get fouled with barnacles etc. which are a pain to remove later on. I use Petit Hydrocoat on the boat and thruster housings with great results. Underwater metals I use a different paint. Every area is different even one cove to the next can be different with marine growth. Ask around where the boat will be moored as to what works best.

 

[knotflying]

Ditto Brian B of Gansett Ranger. I cruise RI & CT. You need bottom paint on the thruster prop, shaft and tunnel. You also need your metal coated with a coating. I use cold Galvanized paint and I have used pettit barnacle barrier. Both have worked for me in our waters.