Tender prop??? Mercury Tempest outboard props, WOW

If anyone needs a great prop for their tender to get it on plane, all I can say is wow.

I just had a brand new Whaler 11' sport rigged with a 40hp Mercury. They come with a 25hp (rated for a 25hp), but they only do 26 mph WOT with that and with 3 people everyone complains they won't get on plane. So we put a 40hp because we want it to stay on plane with 4 people, we didn't care too much about doing more than 30 mph.

Anyways, so I started by putting on a Mercury Black Max 3 blade Aluminum with a 10.3x14P as this is the prop whaler uses on the 13' Sport with the 40hp. What a dog, with it trimmed all of the way down and 1 person, it would not get on plane at WOT unless I leaned all of the way over the helm seat, then after 20 seconds it finally got up...it was not cavitating at all...Weird thing is, once it got up I saw the scariest 32knot speed at 6000rpms (top end of the WOT rpm range for this little bath tub.......With 2 people it wouldn't get on plane unless the second person moved up to the very bow. Some people recommended dropping the motor another pin, installing transom wedges, a larger diameter, a 4 blade prop....drilling ventilation holes in the prop.....

Unfortunately, Nobody has used props laying around for these little motors that you can try. I could borrow a 100 different props for a V6 outboard........I went out on a limb and overnighted a Tempest (4 blade) aluminum in 10.6x 12" pitch. (Smallest amount of pitch for the larger diameter).Figuring a little more diameter and 4 blades would help get it on plane and a little less pitch to help account for the 4 blade and more diameter......Frank and Jimmy's (prop shop) recommended an aluminum on the small 4 stroke because it helps transmit less vibration, which I have to thank them for helping me figure out which direction to go in.

WOW, I test ran it tonight. With 2 big guys, combined weight of 410 lbs, Me in the rear seat the other guy sitting in the middle seat. It jumps on plane in less than 40' and 5 seconds. It's super smooth as well without the vibration the 3 blade had. I still saw just under 6000 rpms as well.......If anyone has a tender with a 4 stroke that is hard to get on plane, the prop retails for $186 and was just amazing. Unfortunately I didn't get any speed tonight because it was rainy, getting dark, and near dark and I didn't feel like grabbing the handheld gps, from inside the salon

The Mercury props will also fit many other engine manufacturers because it has the Torqueflow hub which is easy to change from brand to brand.......I'll try to get speed numbers if I have time. But the performance and drivability was a huge improvement over the 3 blade Mercury prop. Both props were brand new ones that I tested.

I had the same problem, it was a huge dog getting up. A 13" pitch probably would've gotten it up a teeny bit better than the 14", but not like this.

Yes, the Yamaha 4 stroke shares the same hub as the Mercury 40hp 4 stroke (non BIGFOOT) (mine is a 2013). But the hub comes right out of the propellor really easily, to change the hub for different motors with the Torqueflo hub system. Literally you can remove the hub in 10 seconds with a rubber hammer, put in a hub in 10 seconds for a different brand of motor and install it.

What size diameter is your prop? What rpm's are you at now at WOT? The smallest pitch the 10.6" diameter 4 blade comes in is 12", it will probably work for you if you're seeing full RPM's with your 13" pitch. You might, worst case scenario have to reduce the pitch 1" (that's all you can bend aluminum) from the 12" and it's $50 to reduce pitch. But I think the smaller diameter Tempest prop comes in smaller pitch sizes as well. Look up the Torqueflo hub system. More diameter and a little less pitch will help it get up also.

I can tell you, this prop is a world of difference. Getting on plane is like flooring a 65mph waverunner, it just pops right up instantly. Before with 1 person it wouldn't even get on plane unless I leaved foward over the console, then took 30 seconds.

Go to Mercury's website, in the prop section and you can put in your info, the type of boat, and such in the propellor calculator and it will spit out the different props and pitches (sizes) they recommend.

2 reasons. With the 4 strokes the Aluminum helps with Vibration. For some reason you get a lot of vibration with the 4 strokes at slow speeds and midrange and the aluminum helps with that, the stainless transmits a lot more vibration. I noticed the vibration a lot with the 3 blade, and Frank and Jimmy's highly recommended the Aluminum and explained that's why. Also, it helps on a tender with shallow water in mind as you don't destroy the lower unit or have less chance of breakage if you run aground or hit a rock with it. The prop will be sacrificed instead of the lower unit. Honestly I don't think the lower units on these newer 4 strokes are nearly as stout as those old Johnsons and Mercury's that we grew up with. If I was 100% sure I had the right prop for it, I probably would've gone s/s, but figuring I might be buying a few more props I went with Aluminum and everyone raves about this new design if you google it. Also the Aluminum props have come a long way. However, you can only pitch them 1" +/-. The s/s props you can re-pitch about 3" +/-

However, I think the Torqueflo hub would break long before the gear case.....I don't know.......

Ok, I ran the boat today with 2 1/2 guys....... 230lbs, 185lbs and 130lbs......combined weight of 545lbs (25 over the maximum on the USCG capacity plate), keep in mind this is an 11' whaler. Sadly, this boat is definately not a "babe magnet" and I couldn't find any girls wanting to ride in it. It might be different if I was 12 years old. LOL With the 230lb guy (me) on the rear bench, and the 2 other guys on the middle bench......it still jumped out of the hole really quickly.....maybe 8 seconds.....and ran to 6,000rpms.......I saw 28 knots with the 3 of us. Needless to say I'm very happy. I overpowered the boat so the owner could cruise on plane with 2 guys/2 girls, or tow one or two people on a tube or toy with a guy and girl in the boat........ If you read online the 11' with 25hp does 26mph WOT with 2 light people in it, and several people complain that it won't plane with 3 people and a cooler. The 4 strokes don't have half of the low end torque that the 2 strokes had.......

I went up .3" diameter and 2" less pitch and I would say to equal the black max 3 blade (if it's properly pitched to begin with) and you go up .3" diameter, to go down 1" pitch......but on a small boat it's much better to be underpropped than overpropped.