Drive Comparison: OB v Jet v Stern

[skibrain]

Everyone has their preference but this is an interesting read:

http://www.boatingmag.com/boats/boat-engine-comparison-outboard-vs-sterndrive-vs-jet-drive

 

[H20Rat]

As much as the author wanted to make it a drive comparison, those are 3 different boats, ranging from a 17'10" to a 19'6". The pictures are obviously scaled, as the LOA of the outboard is the shortest, yet the picture makes it the longest of the 3...

 

[thumpar]

As much as the author wanted to make it a drive comparison, those are 3 different boats, ranging from a 17'10" to a 19'6". The pictures are obviously scaled, as the LOA of the outboard is the shortest, yet the picture makes it the longest of the 3...

The pictures may have been scaled but did you read it? It is explains the difference. The hulls are all pretty much the same length is is the propulsion and swim platform that changes the LOA. I saw this a week or 2 ago.

You?ll note that the length overall for each boat is slightly different. The outboard?s transom makes that boat 2 inches shorter than the sterndrive. The jet is 18 inches longer than the other two because its extended swim platform is a standard feature. The jet also carries three more gallons of fuel because it has a different tank shape to accommodate its required in-tank fuel pump.

 

[smassey22180]

Interesting read. It is odd that the IO had a 1.62-1 ratio w/ 21p prop. That would explain the slow heavy results. I would love to have an OB bow rider. The problem is 10 year old boats w/ 4 stroke OBs are twice the cost of IOs.

 

[jayhanig]

Where I live on the NC coast, I have one of the relatively few IO boats. When I lived inland, they were very common but not here in the salt water. If I had been smart enough to pay attention to what was before my very eyes, I'd have bought an OB. I'm very limited down here in even finding anybody willing to service the engine or outdrive. IOs make great lake boats.

 

[keith2k455]

I thought it was a nice read with overall some interesting points. I was a little surprised by the poor performance of the IO, but maybe different prop would help that I guess. I agree from a fuel and performance standpoint an OB would be nice, but on board convenience and looks does drive me back to the IO. I always thought a jet woyld be cool, but once cool wears off I'd probably want something else.

 

[bobdec]

Interesting to see a side-by-side comparison. But as mentioned above factors such as usage, boating area should play the major part in engine selection. The boat they tested is an inland waters play/recreational bowrider. The OB is a proven reliable workhorse that works well, but is often overlooked for those types of boats because it's not pretty looking and stereotyped as a fishing/work boat. The I/O setup, engine out of sight from topside is better looking for some, but still very functional is probably the choice of most inland recreational boating selections.. The Rotax 4TEC jet drive is a screaming, 7000 RPM @ cruise and squeezes 250 HP out of 1.5 liters, it's different, shallow water capability and fits a specific niche requirement of the user.

None of those engines will get you more than 3 hours of cruising from 24 gal full to 1/4 tank. The OB is best near 3 hours, the others are hovering around 2 hours. Guess I'm just used to my 150 OB strapped to a 70 Gal tank..

 

[skibrain]

So many additional variables that could be stirred into the mix. I don't think the aluminum props are likely optimal on either the OB or stern drive. I'm also quite sure a 150 E-tec 2-stroke OB is lighter, faster and quicker than the Merc.

 

[Maclin]

I think they now need to do a 2stroke to 4stroke comparo on the OB versions. I imagine the noise would be higher with the 2 stroke but acceleration should be better with the smoker. I do think they did a good job with their research, nice article.

 

[Maclin]

BTW Thanks for posting that skibrain

 

[Tnstratofam]

We have a stern drive v8 in a 20 foot fiberglass bowrider, and a 75hp outboard on a 16 foot aluminum bow rider. The sterndrive has a nice sun pad on the back leading to the swim platform. This in effect gives us allot more useable space at the rear of the boat for sunning, and lounging. It is also much easier for skiers, and swimmers to enter the boat from the water than the outboard. The outboard however has the advantage on maintenance, and repairs over the sterndrive. It is also much easier to winterize. We use the fiberglass boat as our family ski/play boat, and the aluminum boat as our fishing rig. They both work well for their intended purposes.

 

[K-2]

So many additional variables that could be stirred into the mix. I don't think the aluminum props are likely optimal on either the OB or stern drive. I'm also quite sure a 150 E-tec 2-stroke OB is lighter, faster and quicker than the Merc.

That would be my first choice.
But staying with the 3 in the article I would buy the jet.

 

[skibrain]

Maclin i agree, and you can google search and find other comparisons with contemporary 2 vs 4 strokes on same hull. That is another matter of preference and opinion

 

[H20Rat]

The pictures may have been scaled but did you read it? It is explains the difference. The hulls are all pretty much the same length is is the propulsion and swim platform that changes the LOA. I saw this a week or 2 ago.

Yeah that explains the LOA differences. Would be nice if they didn't scale the pics, but oh well... As far as hulls, they do say the jet hull is not the same as the other two.

"Glastron did not simply drop the jet drive into the sterndrive hull and call it a day. There?s a huge weight difference between the two powertrains, and the thrust angle makes the boat handle differently. We were told the jet hull has much less deadrise forward and less lift aft."

 

[Chris1956]

The amount of deadrise is usually proportional to the quality of the ride on rough water. I wonder if the jet boat version, with its less deadrise would ride rougher than the other two hulls.

FWIW, I would choose the OB power. I had a sterndrive here in the salt water. Every spring there would be pieces of rusty metal in the bilge. I never could figure out where they came from, but the motor still ran fine. Of course I had the oil filter rust thru twice and the oil pan rust thru once. Those were nasty...

 

[sickwilly]

I wish they would always add pulling an 180 lbs slalom skier out of the water to the test. I agree that article makes the outboard seem the best of the bunch, but how do they tow?

I finally got to spend some time in a Yamaha jet boat this summer. I loved the room. The one thing I couldn't get over was the feeling that the boat was never fully planning. It was, there was not bow rise and it was moving fast, but it is a totally different sensation from what I am used to. I guess because its sucking in water and pushing it out at the same time. It just never felt efficient to me.

 

[thumpar]

I think they all have their place. Around here unless it is a small aluminum boat or bass boat almost everything is sterndrive or inboard. The lakes are for pleasure so those seem to work best. Even when you go to the west side of the state in the salt they mostly run sterndrive. When you get down south more they tend to be outboard in the salt. This is just my observation no real data.

 

[skibrain]

sickwilly, I've skied behind the 20' version of this hull (with 150 e-tec instead of max-rated 200 hp). The wake was comparable to my brother in law's 2001 Glastron GX180 outboard - better (by that I mean smaller) than most stern drives I've skied behind. OB Hole shot was fine. I/O would have to overcome the 600# weight difference so I assume zero to 20/30 time comparisons are the best indication.

 

[thumpar]

The acceleration times of the I/O would have been much better with a prop that wasn't just for speed.

 

[OrangeTJ]

I wish they would always add pulling an 180 lbs slalom skier out of the water to the test. I agree that article makes the outboard seem the best of the bunch, but how do they tow?

I finally got to spend some time in a Yamaha jet boat this summer. I loved the room. The one thing I couldn't get over was the feeling that the boat was never fully planning. It was, there was not bow rise and it was moving fast, but it is a totally different sensation from what I am used to. I guess because its sucking in water and pushing it out at the same time. It just never felt efficient to me.

We have a Yamaha SX210, which is jet propelled. Love the performance for cruising, pulling tubes, boarders and skiers, land the utilization of space - VERY spacious bow area, wraparound seating in main cockpit and instead of a "sun pad" there is a large two-level swim deck where the kids spend basically all of their time at anchor. I would definitely imagine that the boat will feel a bit foreign to anybody who has spent a lot of time on prop driven boats, as I had prior to buying our Yamaha. I would attribute much of that foreigness to the high revving nature of the engines. Takes a while to get acclimated to cruising at 6 - 8K rpm (which equates to 27 - 47 mph on our boat with a moderate load), but the engines are designed to run in that range and the pumps are most efficient in that range. Sub-planing speeds are really best accompished in forward fast idle or just above, as it takes a bunch more revs to run a couple of mph faster.