Disclaimer: I own a 2004 Lagoon 43 Power Cat, owner’s edition. I am not affiliated with Lagoon in any way, and I am not a professional boat mechanic. I do a lot of research on repairs and upgrades to my boat, and I am sharing my learnings freely here. They may contain errors or not match your boat. Use them at your own risk.
As of late 2024, an entire thrust bearing assembly cost around $2,350 from a Lagoon / Beneteau dealer. (I have used St. Barts Yachts to research and order Lagoon parts.)
In my case, the interior parts of the thrust bearing assemblies were trashed, but the bearing housings were (to my surprise) ok. We measured and researched all the parts that go into the thrust bearings, ordered the parts online, and the shipyard rebuilt them on the bench. Total cost for parts for two thrust bearing assemblies was ballpark $500 with expedited shipping. Note the prices shown on motion.com are list prices and after creating an accounting / signing in, you will see lower prices.
All of these parts are made by SKF. Each seal is doubled up in each bearing (2 fwd 2 aft seals in each bearing assembly). Depending on the condition of your bearing, you may not need all of the parts listed, but these parts are not expensive, and you may want to go with new while you have it apart. Your lock nut may be damaged if your bearings have failed or the prior tabbed lock washer has come loose. More importantly, your shaft may be damaged if it was riding on the nut or other parts after failure. See this post about the shafts. The tabbed lock washers are typically not reused because the tab is only meant to be bent once.
Qty means the number needed to rebuild on thrust bearing assembly. Double the quantity if rebuilding both port and starboard thrust bearings.
Here are the internal parts in order from fwd to aft.
| Where Used Description | Mfg Part Number Qty Link to Purchase |
| Fwd Shaft Seals Single Lip Oil Seal – Solid, 40 mm Shaft Dia., 62 mm OD, 7 mm Overall Width, HMS5 Design, Nitrile Rubber (NBR) Lip Material | 40X62X7 HMS5 RG Qty: 2 motion.com |
| Retaining Nut KM Series Bearing Lock Nut – M45x1.5 mm Thread Size, 65 mm OD, 56 mm Face Dia., 10 mm Width, Steel | KM 9 Qty: 1 motion.com |
| Tabbed Locked Washer MB Series Bearing Lock Washer – 45 mm ID, 69 mm OD, 56 mm Face Dia., Steel Material | MB 9 Qty: 1 motion.com |
| Fwd and Aft Thrust Bearings Tapered Roller Bearing Assembly – 45 mm Bore, 75 mm OD | 32009 X/Q Qty: 2 motion.com |
| Aft Shaft Seals Single Lip Oil Seal – Solid, 50 mm Shaft Dia., 85 mm OD, 10 mm Overall Width, HMS5 Design, Nitrile Rubber (NBR) Lip Material | 50X85X10 HMS5 RG Qty: 2 motion.com |
To share knowledge, corrections, or resources related to this, please email me at my first name @aardsma.com. Thanks, Mark.
See this PDF for full shop drawings about the Lagoon 43 thrust bearing assembly and propellor shaft (in French). Thanks to Mark Kitchens for providing that drawing and much other helpful info.
See also: Lagoon 43 Power Cat Propellor Shaft.