Ask Sail: Straight and True

Before I re-launch the boat should I also have the shop check and true the transmission output shaft to its flange? This is a lot more work, but I’m prepared to do it to get things lined up properly.
Author:
Publish date:

Bruce Colton of Annapolis, Maryland, asks:

The stuffing box on my 1986 Bristol 35.5 has been running too hot, approximately 135F in 80F water. I followed Don Casey’s advice and had the machine shop true the propeller shaft to the shaft flange. The shop shaved 0.008 inch off the flange face. Before I re-launch the boat should I also have the shop check and true the transmission output shaft to its flange? This is a lot more work, but I’m prepared to do it to get things lined up properly.

Don Casey replies:

Unlike the propeller shaft flange, which is field-installed, the transmission flange is a constituent component of the transmission and was installed to the same close tolerances as the rest of the box. The likelihood of any misalignment between the output shaft and the flange is very slight. With the prop flange trued to the shaft, all that remains is to raise, lower, skew and tilt the engine to get the two flanges in perfect bore and face alignment. If your stuffing box then continues to run hot, it is either set up too tight or the packing needs replacing. Gore-Tex or a similar modern packing material should initially be adjusted quite loose to allow for sufficient lubrication to avoid overheating or shaft scoring.

DonCasey

Got a question for our experts? Send it to sailmail@sailmagazine.com

Related

Before-and-after-1_silo

Know How: Cleaning Stainless

Without a doubt, the best way to “clean” stainless steel parts is to have them electropolished. Electropolishing is an electrochemical process that cleans the stainless and removes any surface iron particles, leaving a shiny and far more rust-resistant surface. The downsides of ...read more

catstory

Cruising: Sailing With a Young Family

The dark is alive when you are surrounded by water. Black is tinted blue and silver, and sky meets surf with electricity and the lapping sounds of silence. Inside our 36ft catamaran, moored off Cooper Island in the BVI, the raw nature outside, just now settling down from a late ...read more

IslandPacket349

Boat Review: Island Packet 349

After years of quiescence in the wake of the Great Recession, iconic Island Packet is back with its new 349, a re-boot of the old Estero that not only looks great, but takes the Island Packet style of sailing performance to a new level. Design & Construction First among the many ...read more

190219NEEL51

Video Tour: Neel 51 Trimaran

At this past fall’s Annapolis Boat Show, SAIL magazine had a chance to corner Neel Trimarans founder Eric Bruneel and have him give us a tour of the accommodations aboard the new Neel 51, winner of the “Multihull over 50ft” category in the 2019 Best Boats contest. For a complete ...read more

IMG_0173

Electronic “Flares” for Cruisers

The United States Coast Guard requires that all boats operating in coastal waters or on the high seas carry a selection of visual distress signals. Almost invariably, such signals include the pyrotechnic type, either handheld or fired from a flare pistol, but surely there are ...read more

M2-HOOK-TOP-AND-CHAIN-1

Gear: M2 Chain Hook from Mantus

Stay Hooked Chain hooks on anchor snubber lines tend to fall off when you least want them to. Not so this latest example from Mantus. The M2 Chain Hook is secured to the chain by a simple elastic strap, so it won’t come off when the snubber loosens. Made from corrosion-resistant ...read more