Spare Prop and Hub Kit

[zul]

Motor is a 75hp outboard 1996 ELPTO Mercury with a stainless Solas 13x21 speed prop. The prop does well in most areas, 38mph @ 5200 rpm but it does 'porpus' or spin air in the turns (mid speed and full speed turns). I do not have a spare prop which I am trying to get right now. Any suggestions on where to buy or specific sized/pitch prop that might not spin out?

I've got an aluminium prop sourced from West Marine, 13x19 but it's $160.

Do I need a hub kit? That's another $60.

Thanks for the advice in advance!!

zul

 

[Scott Danforth]

trim down.

porpoising and ventilation are two different things. both occur when you are trimmed up too far.

 

[steelespike]

It's not unusual to have to trim down for turns and porpoising.
Is your prop in excellent condition? Is the anti vent plate(just above the prop) about even with the bottom?
Your not likely to be happy with an Aluminum prop going from stainless.

 

[zul]

Yes, my current prop is in prime condition. I am just looking for a backup prop. Was even thinking about an old rebuilt prop to save some money.

Is there some difficulty in switching from alu to ss? I am hoping for a simple swap out if possible. That's why I'm confused on the hub kit - would the stainless prop have the same hub? If the origional hub slides out -- would it fit other props?! -- Everything is compatible, right (eek)@!!

No, I haven't pulled my prop off yet. So I don't know if the hub slides out or if it's pressed in sorta permanent style.

I really want to get the right items to keep me out of a jam, especially if I am deep on the lake.

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Is the anti vent plate(just above the prop) about even with the bottom?
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Hmm, not sure if I understand the question. There is room for the blades all around. ??

This used to be so much easier in the 80's. Ha ! !

 

[flyingscott]

If you buy a prop with a removeable hub you must buy the hub with it. Even if you have props from the same manufacturer with hubs,when you hit something the hub is usually damaged, so you need replacements. Some people will carry only a spare hub I am not a fan of that. If it's a spare prop get a decent one because you don't know how long you will be using it. The cavitation plate on the motor when set-up properly will be even with the bottom of the boat has nothing to do with the prop. Your cavitation and porpoising is because your motor is trimmed up to high.

 

[steelespike]

Your motor can be mounted at varying heights the antiventplates relation to the bottom of the transom is a way of telling how high the motor is mounted.
Your experiencing ventilation in turns(prop loses its grip)This can be an indication the motor is mounted too high and/or trimmed up too far.
The relation of the anti vent plate to the bottom of the transom will tell us how the motor is mounted.Usually stated like about even our slightly above or slightly
below.Lay a straight edge along the keel out to the anti vent plate should give actual dimension. Plate should be parallel too the bottom.
No two boats are likely to have the same mounting height.
If it is also porpoising that is an indication you are trimmed up too much.A motor may not trim up the full range.It needs to be trimmed for best speed and handling.

 

[Scott Danforth]

to further comment, see post #2. you do not have a prop problem, you have a ventilation and porpoising problem. your either trimmed up too far, or as steelespike inicated, your motor is too high

there is not a prop fix for that.

once you fix that problem, and you want to buy a spare prop. you buy the complete prop, and hub kit for that prop and your motor. I also recommend buying spare prop nuts, locking collar and splined washer. because you will most likely drop one in the water when changing a prop at sea. Buying props at West Marine is more expensive than your local dedicated propeller shop, or here on iBoats.com http://boatpropellers.iboats.com/?cart_id=080353787&session_id=513772922