Maybe I'm over hauling

[RyanTexas]

HI all,
I have total 9 passengers, mixed children and adults on my boat yesterday. Small backpack cooler and a paddle board. To get my Yami210 on plane, I had to push to 8500 rpm. Is that normal for you ? My sterndrive boat doesn't do that, I can cruise 20mph on plane without a problem with the same number of people.

Thanks

 

[mrcleanr6]

i dont have a 21 but my 08 232 needs about 7000 to stay on plane with just me and a couple adults on board. to initially get on plane i need a little more then i can throttle back but below 7k i will start to fall off.

 

[212s]

I have total 9 passengers, mixed children and adults on my boat yesterday. Small backpack cooler and a paddle board. To get my Yami210 on plane, I had to push to 8500 rpm. Is that normal for you ? My sterndrive boat doesn't do that, I can cruise 20mph on plane without a problem with the same number of people.

Jets rev higher to build pressure in the pumps for thrust so more rpm is natural. My old stern drive cruised at 3000rpm, but at that level, jets are just building good pressure. My new jet cruises nicely at 5000rpm or higher, that's 600rpm higher than redline on the old stern drive! But it's normal rpm levels. I can be solidly on plane at 22mph and about 4900rpm and the boat will take a while to plane out at those levels unless you give it some extra throttle to get it up out of the water, then back off to cruising rpm - prop boats are more efficient at developing thrust so they don't need as much rpm to get up on plane. I typically cruise at 5100rpm and 27mph which gives me the best mileage rating for longer distances and while going exploring in new areas. Your engines are probably the MR-1 ? and they rev a little higher than the 1.8l engines in mine.

Jets also are more sensitive to heavy loads and weight distribution due to the thrust differences. So a fully loaded boat will take more rpm and thrust to get moving, but once on plane, you should be able to cruise around just fine.

 

[captras]

With a full tank of gas, 5 adults, and 2 kids, I easily get up on plane 5500-6000. Cruise at around 30MPH at 6000 RPM. Oh that load includes 2 medium size coolers with drinks and food.

 

[M2krafty]

With the 210 and less power, I think that's normal. The difference between a loaded boat and an unloaded boat is stark. After a weekend with a full boat I'm usually pretty frustrated with it. When I'm out with a few people and good weather, I feel like it's a different boat. Frankly comparing the 24's or the 212 boats with the 1.8's is not helpful. Different boat entirely.

 

[Babin Farms]

When I have my family of 4 my boat is totally different than when I take our friends family to make a total of 8-9. Take more throttle & a bit more time to get on plane with the extra weight. My guess is that your stern drive is just not as noticeable.
Cars, trucks, boats, planes, trains or anything else. The more weight you tow or haul the more power/torque your going to need to get the load up and going.

 

[M2krafty]

When I have my family of 4 my boat is totally different than when I take our friends family to make a total of 8-9. Take more throttle & a bit more time to get on plane with the extra weight. My guess is that your stern drive is just not as noticeable.
Cars, trucks, boats, planes, trains or anything else. The more weight you tow or haul the more power/torque your going to need to get the load up and going.

I think you hit the nail on the head. It's a matter of torque and the nature of the jet/pressure situation. The V8's usually found in the stern drives supply a lot of torque and will likely deal with the higher load better without revving a bunch more. I've seen the same situation with tubing on turns with my smaller yamaha motors. I loose a lot of speed where a stern drive won't. Still, the 1.8's handle it much better from what I understand.

 

[RyanTexas]

The next day, I had 6 people including myself and it was on plane quickly. We cruised at 30mph somewhere near 7k rpm.

 

[M2krafty]

I have also found that with a really big load it matters where people sit (if nobody is in the bow you're screwed). This was always true with stern drives, but usually wasn't as much of an issue with Jets.