Aluminum to Stainless Question...

Discussion in 'Boat Yard Basics' started by nmcphail, Apr 7, 2010.

  1. nmcphail

    nmcphail I Love microskiff.com!

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    When switching from an Alum to SS prop can you go with the same dia./pitch, or do you need to compensate for a change in material by changing a little on the diam./pitch?

    I have a Merc 25 2stroke and am pretty happy with the stock 10 3/8-13 aluminum prop but am thinking about going over to SS b/c of the durability.

    I see more options available for 10-13 SS props and am wondering if the small change will make a difference or do I really need to find a true 10 3/8-13.

    Sorry for the rambling...
     
  2. mark_gardner

    mark_gardner I Love microskiff.com!

    well first off you really need to know how many rpms your motors turning before you do anything, once you figure out where shes at rpm wise running how you would normally run with the load (weight ) you normally carry you then can adjust your pitch up or down in order to get the motor where shes running in the upper max rpm range at w.o.t., being its a merc 2 stroke the max rpms are 6000 so i would adjust prop and pitch size trying to get as close to that as i could, typically a ss prop of the same size is going to spin a lil more rpms, i am running a aluminum 13 pitch prop and with an average load i'm hitting about 5300 rpm at w.o.t. so i just ordered and recieved a new power tech 13 pitch ss prop today that i'm hoping should put me a little closer to the 6000 mark
     

  3. nmcphail

    nmcphail I Love microskiff.com!

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    I'm running it on a 14' jon, front deck and poling platform, but pretty light loads usually.

    The Tiny Tack says about 5600-5800 if I remember correctly, but the prop really needs to be refinished.

    Where did you pick up the SS Powertech?  Any reason to go with PT over another brand?
     
  4. mark_gardner

    mark_gardner I Love microskiff.com!

    well power tech has a good reputation so i'm feeling pretty good about that ;) i called power tech asking about available local dealers and the guy on the phone suggested i log on to "getaprop.com" says they have the lowest price i'll find anywhere on the power techs so i call and order..... i ended up paying $180 something ? plus shipping and had the prop within days :cool: but before i bolt it on i think i'm gonna pick up a new prop nut first ;D sounds like you need the same thing based on your current readings :-?