Propeller shaft vibrations on ip35

George:
No IP needs a strut or bearing on the shaft. I have sailed and motored out IP 35 since 2001 and we have 35,000 nm under her. This vibration is always caused by a bad out of balance prop. Many IP 35s and IPs in the 1990s opted for the "factory upgraded" feathering $3,000 option prop by the knock off company called PROWELL. These props over time will develop a different pitch on each blade becuase the blades stop up against a bronze stop. This stop mushrooms over and then the blades are at a different pitch. Today, these props can be serviced by Veri-Prop USA. Personally I would toss out a prowell prop, we did and we were so happy to toss it overboard.

If the vibration is not from one of these upgraded PROWELL feathering props then it could be from an unbalance fixed three balded prop.

If not the prop then it is the motor mounts and a mis-aligned engine.

Do not re-engineer the IP35, it is just fine the way it is designed, like most IPs. Prop shaft vibration is always from one of these issues:
Prop Blade pitch difference
Motor mounts
out of aligned engine

Hayden
www.svIslandSpirit.com 12 years of IP35 blogging stories

Shawn:
We have the original 3 bladed fixed prop which is a 14" pitch x 17" diameter, if I recall. We have the 38 hp Yanmar 3JHH2e, we run at 2600 rpms. Wer too will get the typical oil on the stern. This is due to the stern digging in and lowering when runnig PLUS the fact that the exhaust is deposited into the back wash of the water coming off the stern. To reduce this, some have added a 24" piece of fire hose clamped to the exhaust to deposit the exhaust into the water that is flowing aft and not circling back into the hull.

Every old 2 digit IP has this oil on the stern due to a poorly designed underbody stern shape and the poor trailing stern wave. If the stern were lifted like on the 3 digit boats with a diving platform,..,.,ugh ...I mean a swim platform/sugatr scoop then this lifted stern is OUT of the stern wave and the water trails off the back properly.

So, do not think it is all engine or prop. It is hull design as well.

The other thing you can do is to move weight forward. On the IP35, we have every spar part, every heavy item in the most forward vee berth locker under the bed. This helps to drive the bow down and lift the stern.

I hope this helps. Sorry for the delay, we are moving around the USVI

Hayden