Side Thruster Anodes

Our new to us 2019 C28 has no anodes on the bow and stern thruster propellors. It looks like they may have have been present in the past, but have completely degraded in salt water. Does anyone have a part number or dimensions for these zincs? I assume they are conical in shape and held with a stainless hex nut to the propellor shaft?

BoatZincs dot com. If you have the Side Power thrusters the part number for the aluminum anode is SM31180A Side-Power Aluminum Anode. My 2017 C-28 has the Side Power thrusters. Check yours to be sure. And understand the differences between aluminum, zinc and magnesium anodes. I’m all aluminum for longer life in salt water.
Yes, anode secured with stainless bolt. You get new bolt with anode purchase. Bow thruster anode bolt can be difficult to reach. Stern bolt is much easier. Once old bolts out it’s easy to install the new anodes and bolts.

Thanks for the info! I thought Aluminum was for fresh water or brackish water?

Per BoatZincs web site:

Answer T7: Your choice of anodes requires consideration of:

• The kinds of underwater metals on your boat (e.g., stainless steel, bronze, aluminum, mild steel); and,
• The kinds of water you operate your boat in (e.g., salt, brackish and/or fresh).

Mil-Spec Zinc is the traditional anode choice for saltwater vessels.

Mil-Spec Aluminum anodes are for use in all types of water: Salt, Brackish, and Fresh. They are an alternative to zinc anodes as they are 1) more active, 2) provide better self-cleaning performance, and 3) offer a longer service life. They are preferred for protecting vessels with marine grade aluminum underwater metals.

Mil-Spec Magnesium anodes are the best choice for fresh water vessels (only).

Thanks again for your replies. I ordered the anodes from Marine Depot Direct. I'll try Boat Zincs.com next. Due to age, I'm retiring from 40+ years of sailing Catalinas. The Catalina Owners Association has an excellent forum and most replacement parts are available through an unaffiliated supplier called Catalina Direct. When we purchased the Cutwater 28, I was concerned that technical information and parts would become difficult to come by and instead have found the Tugnuts forum and parts replacement readily available....adding to the great experience of Cutwater ownership.

scross said:

Per BoatZincs web site:

Answer T7: Your choice of anodes requires consideration of:

• The kinds of underwater metals on your boat (e.g., stainless steel, bronze, aluminum, mild steel); and,
• The kinds of water you operate your boat in (e.g., salt, brackish and/or fresh).

Mil-Spec Zinc is the traditional anode choice for saltwater vessels.

Mil-Spec Aluminum anodes are for use in all types of water: Salt, Brackish, and Fresh. They are an alternative to zinc anodes as they are 1) more active, 2) provide better self-cleaning performance, and 3) offer a longer service life. They are preferred for protecting vessels with marine grade aluminum underwater metals.

Mil-Spec Magnesium anodes are the best choice for fresh water vessels (only).

Click to expand...

From what I've found out, the Lewmar thrusters on my 2025 R29-CB need to use aluminum anodes because they are protecting aluminum components. I use zinc on everything else.