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Posts: 36
| Hi guys,
i'm looking for your adivse on props. I would like to know the pros and cons of having a stainless steel props.
in order for you guys to give me the best advise, my boat is a Sylvan Expedition 17 equipped with a F115 Yamaha. The boat fully loaded 3 guys plus gear, we top end at around 38-40 MPH motor trim up. I currently run a 13 1/2 inch diameter with 19 pitch aluminum prop.
I've heard that they've created a plastic yoke that would go inside the stainless steel props so that if you it something the yoke would break before the actual shaft. Is there such thing or the shaft will still be damage or even break.
Is there any advantage of getting a stainless steel prop keeping in mind that i like to troll in shallow water for musky?
thanks. |
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Posts: 5874
| I'm sure Steve(VMS) will be here soon. He's really good with props.
But need some information. Assuming 3-blade aluminum prop now? What are your WOT RPM's? Loaded and light load? How is your holeshot?
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Posts: 3508
Location: Elk River, Minnesota | Hiya,
Shep was right...I'd stop in and see this....
Shep also has asked the right questions to begin with. In order to get a better idea of what your boat is doing now, getting the full throttle RPM value is really the tell tale of where you are at now given your speed listed. If you can get them with just you and your gear in the boat that would be great!!
In most cases, when people own a motor that is 90hp and above, they can really benefit from going to a steel prop...the first and foremost reason is handling. Steel props (unless they are the steel equivalent like an omc SST prop) are made to be thinner just due to their strength and durability. This allows the fins to bite the water much more efficiently than a standard aluminum with their blunt leading edges due to thickness. This also allows the design of the fin to incorporate more cupping on both the tip and trailing edge, lifting the bow (tip cupping) and the rear (trailing edge cupping) depending on the manufacturer's design, and the amount of rake (how much the fin is swept back from being at a 90 degree angle from the prop), which also adds bow lift. Props like a yamaha pro series, OMC raker, and even the michigan rapture all show rake when you look at them.
In most cases, a switch to steel will require the owner to drop down an inch or two in pitch as the prop flexes much less than a standard aluminum, thus the motor has to work harder to turn the prop.. At times, though, you can raise the motor up a couple bolt holes to gain some rpms back if you decide to drop only 1 inch in pitch.
Many manufacturers are now building props with that plastic hub which is designed to work on many different brands of motors, which is a very nice feature. Mercury does this with their props...and they make some of the best out there in both 3 and 4 blade models. There is some cushioning that the hubs give on a slow speed strike, where they will break off and spin, which saves the lower unit from damage. Under a high speed strike, neither steel or aluminum will save the lower unit as such a hard hit with an object that in most cases does not move (like that wonderful granite we find in many Canadian waters), a bent shaft is very common. I have seen where one friend of mine (who is no longer with us) seemed to use his lower unit to find many rocks on a remote Canadian lake. One year he sheared the lower unit completely off where it attaches to the midsection.
So...in a nutshell...
-Steel flexes less and is made thinner for better bite on the water, and has many more designs to accommodate what your needs are.
-Going to steel usually requires dropping 1 - 2 inches in pitch to maintain RPM's
-XHS hub systems will help cushion slow speed strikes, and allows for use on multiple brands of motors.
I hope this gives you a little insight into what steel will do for you, and if you choose to go steel, I would love to hear where you are at now and what you could potentially see out of the boat.
Steve |
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Posts: 620
Location: Seymour, WI | I'm not a motor head like Steve or Shep, but my own experience with a Yamaha motor and stock Yamaha aluminum prop is that the Yamaha aluminum prop fits that motor very well and has very good handling and performance.
When I experimented with steel props I really didn't see any performance improvement and I ended up just liking the feel and lower cost of the aluminum prop better.
For me, spending an extra $200 - $300 on a steel prop was not worth it to get an add'l 1-2 MPH in top end speed.
Grass |
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Posts: 36
| Hi Steve,
currently, if i'm not mistaken, my motor is mount either on the last or second last bolt of the mount. As for my RPM, the maximum i've gone is 5500 rpm (past 5500 rpm motor sounds off a little bit as it seem to rev to high) crusing at around 38-40 mph (depending on weather and water current).
I use my boat to travel from spot to spot at full speed or I'm trolling. I currently have a 3 blade aluminum so would you recommende staying with a 3 blades or a 4 blades.
thanks. |
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Posts: 3508
Location: Elk River, Minnesota | Hiya,
I think you can stay with a 3 blade without too much issue. Your boat weighs alone at just over 1400, and that is a very common weight with a 115 hp motor on it. The boat is rated to 150 if my research is correct. With your aluminum now at 5500 rpm and speed of 38 to 40...I'm assuming that is with the 3 guys and gear? If so, that probably is not too far off as the max for the f115 is 6000 and would happen under light load. How are RPM's when you are by yourself with just your gear and how well does the motor trim the boat?
Steve |
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Posts: 36
| Hi,
it's been a while that i haven't fish alone. The boat is rated for max 135 HP. I feel that the motor trims the boat well but it's my first boat therefore no background experience to compare with.
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Posts: 3508
Location: Elk River, Minnesota | Hiya,
If you can, take a ride with the rig alone and trim to the best possible position you can (just before the prop lets loose or bow starts to porpoise). Then, take note of the max rpms at that point. That will give us a good starting point for potential options.
Steve |
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Posts: 36
| hi,
Perfect I will do my homework and get back to you.
thanks Steve!! |
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Posts: 29
| Here's an alternative. Check out piranha props. Stiffer than aluminum, cheaper than steel and easier to fix. Just replace the blades. Hub is guaranteed for life. When purchasing, you can keep trying blades of different pitch until you find the best setup for your boat.
I have one and I am very satisfied with it. |
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Posts: 3508
Location: Elk River, Minnesota | Hiya,
Piranha props would be a nice spare, but in trying to find the most efficient set up for a rig of the size and horsepower mentioned here there are many many many more options in steel props.
Piranha props are made using the same design for each fin, but in different pitches. The ability to have more raked fins, cupping, vent holes, etc are not available. The composite might be stronger than aluminum but it will still flex quite a bit more than steel, which reduces its ability to bite the water well. That equates to not being able to play with motor height and the motor itself will not respond as well to trim.
It would be a good prop, but in my humble opinion, best left to be a spare
Steve
Edited by VMS 8/16/2014 2:01 PM
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Posts: 16632
Location: The desert | Steve, I think I need to take you for a ride in my boat and see what you'd recommend! |
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Posts: 3508
Location: Elk River, Minnesota | Id be happy to sometime. Last I remember of your major fishing ventures were back shire fishing at point. What did you get for a rig? |
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Posts: 16632
Location: The desert | VMS - 8/16/2014 5:19 PM
Id be happy to sometime. Last I remember of your major fishing ventures were back shire fishing at point. What did you get for a rig?
1890 Osprey T with a 90 Opti.
I'm over in Ashby now so if you ever want to give the lakes over this way a whirl, I'm always game. |
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Posts: 791
Location: WI | Last year in canada I decided to put my spare aluminum prop on to eliminate the chance of wrecking my trip. This was a very good test because I have used the same ss prop for the life of my boat. I was astounded by the loss of performance. I lost several mph and worse gas milage. But the worst part was the loss of grip and hole shot. It was actually hard to force the boat on plane with out cavitation. Same size and pitch props. Huge difference. |
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Posts: 36
| Hi Steve,
i've done my homework and here is some info.
first my motor is mounted on the highest hole on the braket. Alone in my boat with my gear I can run at 5 500 and crusing at 39-40 mph but the engine sounds to be close to the redline. The motor is trim to the max, that if i trim it again the prop would let loose.
Again my boat is a Sylvan 17,1 foot long with a Yamaha 115. The wight of the boat (dry) is 1 200 lbs but then you have to add the motor (just under 400 lbs I think) and the gaz 30 gallons and 3 batteries and the fishing gear. I currently run a 13,5 diameter and 19 pitch aluminium blade.
what would be your best recommandation given the information that i've provided you. Feel free to ask any question in order to get a better picture of the situation.
thanks again. |
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