Selecting The Correct Prop

Written by Todd S. Go2marine/LFS Tech Support

Let’s go over the types of props. Solas propellers offer distinct features that set them apart. One noteworthy aspect is the rubex propellers, which come with interchangeable hubs. This allows for versatility and adaptability based on specific needs. Additionally, Solas also manufactures propellers with pressed-in hubs, providing a different design option. Each type of propeller caters to different requirements, ensuring boat owners have a range of choices for optimal performance. There Rubex props with removeable hubs, Rubex Aluminum Prop and then pressed in hubs Amita Aluminum Prop for stern drive and outboard boats.

 

The Hub Kit is the center part of the prop that splines onto the prop shaft. It consists of a dense rubber outer layer and a brass insert which splines onto the prop shaft. If you have spun a hub in a prop that the hub can be replaced, then you can purchase a hub kit for it instead of having to replace the whole prop.

 

To change a prop, you will need a small piece of 2x4 lumber, needle nose pliers, and a socket or Prop Wrench. Start by inserting the wood in between the prop and the lower unit. Spin the prop until the wood is wedged in between the prop blade and lower unit. Remove the cotter key or bend the locking tabs back to remove the nut from the prop shaft. Then if there is a spacer or washer remove it after the nut. Remove the prop at this point, you will see a thrust washer after the prop is removed. There is no need to remove it unless there is damage to it.

 

Once the prop is removed if it has a removable hub, you will see a square outline on the side of the prop that goes on first. It can simply be pushed out toward the side with the opening opposite the nut goes on. If it struggles to come out, you can use a hammer and a flat head screwdriver to knock it out. Noticeably on the new hub kit you will see the inside brass part protruded out on one end, that will be the end that goes in the prop first towards the prop nut end.

 

If you have a prop that has a glued in hub they cannot be changed, you will have to purchase a replacement prop. Every prop will have a diameter and pitch stamped on the prop, usually on the hub part of the prop. Those are the numbers that can be cross-referenced in order to find the correct prop for your boat. See our prop finder tool here.

 

Pitch is the distance a prop would move in one revolution, ex a 19-pitch prop will move 19" per revolution. If the pitch is lower that increases rpm, usually 1 inch is equal to about 150-250 rpm. EX: going from a 18 pitch to a 16 pitch will increase the rpm about 400 revolutions. Lower pitched props will get you out of the hole quicker at takeoff, where high pitched props will give you more top end speed.