1985 Outrage 18 with Twin Yamaha F70 Engines

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Author Topic:   1985 Outrage 18 with Twin Yamaha F70 Engines

cj85 posted 01-05-2014 02:33 PM ET (US)
I'm looking for some help in propeller selection for my 1985 OUTRAGE 18. The boat will be running twin 2013 Yamaha F70 four-stroke-power-cycle outboard engines. The engines are on 8-inch setback manual jack plates. The boat is probably a little heavier than a factory one due to pilot house (much like a pacific pilot house but custom built) along with electronic package (radar, multiple screens, autopilot and multiple batteries under house). I'm not concerned about the added weight since the boat will fish no more then two guys ever and usually one. The boat is only used to fish the ocean, primarily in central [California]. My main concern is planing quickly. Economy is also important since the boat will be used offshore when conditions are correct. I'm not worried about maxing out the hull's speed capabilities. A top speed of 35-MPH would be more then enough for me, and the ocean usually doesnt allow for speeds in excess of that, anyways. Additional info about the engines. [Full throttle engine speed is the range of] 5,300 to 6,300-RPM. They have a gear ratio of 2.33:1. They are both normally rotating since 70-HP engines are not offered with counter rotation. The engines are not yet hung so I have no [performance] data to offer other. I am trying to get a good starting point with my propeller selection. Thanks--cj
cj85 posted 01-05-2014 02:44 PM ET (US)
As an after note: when I bought my engine package I got Yamaha stainless propellers included. I just have to pick a size. I would prefer to stay with those propellers (since they are paid for), but, if there is a better prop available, then I'm OK with forking out the extra money. The Yamaha propellers will just have to be back up propellers. Thanks--cj
Tom W Clark posted 01-05-2014 06:02 PM ET (US)
Which Yamaha stainless propeller model? Yamaha offers six different stainless steel models that fit the F70 that I can think of off the top of my head.
The pitch will depend, to some degree, on the specific model of prop, but you'll probably end up with 15" or 16" pitch props.
With the pretty significant rear weight bias, you may want a good stern lifting propeller. Consider the large blade area, low rake, Yamaha Pontoon Performance Series model. You would want the 14" x 15" pitch version.
The semi-cleaver design of the Yamaha Painted Stainless Steel model may work well too. You would want a 13-1/2" x 16" version of that propeller.
jimh posted 01-07-2014 10:48 AM ET (US)
Your plan sounds very similar to the set-up that Dave (aka Buckda) used on his OUTRAGE 18 when he powered it with twin 90-HP E-TEC two-stroke-power-cycle engines mounted on setback brackets. That was a very nice set-up for the OUTRAGE 18. It was a fun boat to drive and it seemed to run very well, even with all the weight on the transom from the twins and the setback bracket. I think your twin 70-HP boat will be very good for your ocean fishing use.
It will be interesting to see if you can push the boat onto plane with just one engine. Since you describe your boat as being already heavier than normal, it may be marginal to reach plane with a single 70-HP.
Buckda posted 01-07-2014 06:19 PM ET (US)
The weight of a pilot house might offset the weight of the engines back there. When I had my 18 fully loaded for week-long camping/wilderness excursions, the weight I carried forward of the console really made the use of trim tabs a non-issue - and smoothed out the ride quite a bit.
I agree with Tom...I ran 19" pitch Stilletto Advantage ss propellers on my rig - with twin 90 HP E-TEC engines on 10" setback brackets - i was very pleased with the performance...wish I never sold.
cj85 posted 01-08-2014 12:48 PM ET (US)
Thank you for the responses. We never discussed which line of props. I will have to call my dealer. I have based a lot of what I've done from buckda's 18 outrage. There are a lot of whaler folks that try to tell me it can't be done or won't work. Once the boat is done I will post pictures on this site. It's highly modified in other ways as well. Once again thank you for the input.
Cj
Buckda posted 01-08-2014 01:34 PM ET (US)
Excellent.
With your heavy setup, I'll add that you'll be happier with the lower pitched props. Mine was propped for upper speed rather than low end grunt. When my brother-in-law and I were on lake Nipigon, ON for a week with a VERY loaded boat, the time to plane suffered a bit, and the engines lugged a little. Couldn't probably plane on one engine when loaded like that.
With 4-stroke 70's, the lower pitch will definitely help you pop up on plane with only one engine.
cj85 posted 01-08-2014 01:57 PM ET (US)
OK, I just got off the phone with my dealer. He uses solas props, not yamaha props. They are stainless but nothing matches the numbers that tom has provided. There are many that are close but I do not have enough knowledge of props to make a determination of what would work. If nothing that they offer is correct I suppose the solas props could be bought as back ups and something a little more high end may have to be purchased. At this point spending a little more to get it right if necessary is fine.
cj
Buckda posted 01-09-2014 09:06 AM ET (US)
When you get your boat back, be sure to take some photos - would love to see your rig.
Dave
Tom W Clark posted 01-09-2014 12:52 PM ET (US)
Solas makes at least three stainless steel propeller models that will fit the Yamaha F70, the New Saturn, Titan and Titan 4. I have no personal experience with any of them.
Regardless, they are all offered in odd numbered pitches so you will probably want a 17" pitch version of whatever model of Solas propeller the dealer is offering (probably the cheapest).
Propellers are not generic pieces of hardware that can simply be described by pitch and diameter, so you don't go looking for a substitute of one brand for another by matching pitch and diameter; it is a little more complicated than that. You must consider the attributes of the particular model of propeller being considered.
cj85 posted 01-10-2014 01:58 AM ET (US)
Tom thank you for the education about props. I've owned 4 boats before the outrage (7 engines) and I've never had to deal with buying a prop. I've checked out all the solas props you mentioned. They all seem like they have possibility and fit the criteria. I think I like the titan 4 because of its good stern lifting properties and minimal cavitation. Second I like the Saturn for its heavy load capabilities. I'm still not sure I completely understand props. I'll call my dealer and see what I can get. Once the boats done I will post some performance numbers and if it plans on one engine(I'm more curious about this then anything else). I also plan on weighing the boat to get an idea of how much excess weight I have. Thanks again everyone.
Cj
Peter posted 01-10-2014 06:50 AM ET (US)
Propellers are like shoes, you have to try them on to see what fits best.

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Author	Topic: 1985 Outrage 18 with Twin Yamaha F70 Engines
cj85	posted 01-05-2014 02:33 PM ET (US) I'm looking for some help in propeller selection for my 1985 OUTRAGE 18. The boat will be running twin 2013 Yamaha F70 four-stroke-power-cycle outboard engines. The engines are on 8-inch setback manual jack plates. The boat is probably a little heavier than a factory one due to pilot house (much like a pacific pilot house but custom built) along with electronic package (radar, multiple screens, autopilot and multiple batteries under house). I'm not concerned about the added weight since the boat will fish no more then two guys ever and usually one. The boat is only used to fish the ocean, primarily in central [California]. My main concern is planing quickly. Economy is also important since the boat will be used offshore when conditions are correct. I'm not worried about maxing out the hull's speed capabilities. A top speed of 35-MPH would be more then enough for me, and the ocean usually doesnt allow for speeds in excess of that, anyways. Additional info about the engines. [Full throttle engine speed is the range of] 5,300 to 6,300-RPM. They have a gear ratio of 2.33:1. They are both normally rotating since 70-HP engines are not offered with counter rotation. The engines are not yet hung so I have no [performance] data to offer other. I am trying to get a good starting point with my propeller selection. Thanks--cj
cj85	posted 01-05-2014 02:44 PM ET (US) As an after note: when I bought my engine package I got Yamaha stainless propellers included. I just have to pick a size. I would prefer to stay with those propellers (since they are paid for), but, if there is a better prop available, then I'm OK with forking out the extra money. The Yamaha propellers will just have to be back up propellers. Thanks--cj
Tom W Clark	posted 01-05-2014 06:02 PM ET (US) Which Yamaha stainless propeller model? Yamaha offers six different stainless steel models that fit the F70 that I can think of off the top of my head. The pitch will depend, to some degree, on the specific model of prop, but you'll probably end up with 15" or 16" pitch props. With the pretty significant rear weight bias, you may want a good stern lifting propeller. Consider the large blade area, low rake, Yamaha Pontoon Performance Series model. You would want the 14" x 15" pitch version. The semi-cleaver design of the Yamaha Painted Stainless Steel model may work well too. You would want a 13-1/2" x 16" version of that propeller.
jimh	posted 01-07-2014 10:48 AM ET (US) Your plan sounds very similar to the set-up that Dave (aka Buckda) used on his OUTRAGE 18 when he powered it with twin 90-HP E-TEC two-stroke-power-cycle engines mounted on setback brackets. That was a very nice set-up for the OUTRAGE 18. It was a fun boat to drive and it seemed to run very well, even with all the weight on the transom from the twins and the setback bracket. I think your twin 70-HP boat will be very good for your ocean fishing use. It will be interesting to see if you can push the boat onto plane with just one engine. Since you describe your boat as being already heavier than normal, it may be marginal to reach plane with a single 70-HP.
Buckda	posted 01-07-2014 06:19 PM ET (US) The weight of a pilot house might offset the weight of the engines back there. When I had my 18 fully loaded for week-long camping/wilderness excursions, the weight I carried forward of the console really made the use of trim tabs a non-issue - and smoothed out the ride quite a bit. I agree with Tom...I ran 19" pitch Stilletto Advantage ss propellers on my rig - with twin 90 HP E-TEC engines on 10" setback brackets - i was very pleased with the performance...wish I never sold.
cj85	posted 01-08-2014 12:48 PM ET (US) Thank you for the responses. We never discussed which line of props. I will have to call my dealer. I have based a lot of what I've done from buckda's 18 outrage. There are a lot of whaler folks that try to tell me it can't be done or won't work. Once the boat is done I will post pictures on this site. It's highly modified in other ways as well. Once again thank you for the input. Cj
Buckda	posted 01-08-2014 01:34 PM ET (US) Excellent. With your heavy setup, I'll add that you'll be happier with the lower pitched props. Mine was propped for upper speed rather than low end grunt. When my brother-in-law and I were on lake Nipigon, ON for a week with a VERY loaded boat, the time to plane suffered a bit, and the engines lugged a little. Couldn't probably plane on one engine when loaded like that. With 4-stroke 70's, the lower pitch will definitely help you pop up on plane with only one engine.
cj85	posted 01-08-2014 01:57 PM ET (US) OK, I just got off the phone with my dealer. He uses solas props, not yamaha props. They are stainless but nothing matches the numbers that tom has provided. There are many that are close but I do not have enough knowledge of props to make a determination of what would work. If nothing that they offer is correct I suppose the solas props could be bought as back ups and something a little more high end may have to be purchased. At this point spending a little more to get it right if necessary is fine. cj
Buckda	posted 01-09-2014 09:06 AM ET (US) When you get your boat back, be sure to take some photos - would love to see your rig. Dave
Tom W Clark	posted 01-09-2014 12:52 PM ET (US) Solas makes at least three stainless steel propeller models that will fit the Yamaha F70, the New Saturn, Titan and Titan 4. I have no personal experience with any of them. Regardless, they are all offered in odd numbered pitches so you will probably want a 17" pitch version of whatever model of Solas propeller the dealer is offering (probably the cheapest). Propellers are not generic pieces of hardware that can simply be described by pitch and diameter, so you don't go looking for a substitute of one brand for another by matching pitch and diameter; it is a little more complicated than that. You must consider the attributes of the particular model of propeller being considered.
cj85	posted 01-10-2014 01:58 AM ET (US) Tom thank you for the education about props. I've owned 4 boats before the outrage (7 engines) and I've never had to deal with buying a prop. I've checked out all the solas props you mentioned. They all seem like they have possibility and fit the criteria. I think I like the titan 4 because of its good stern lifting properties and minimal cavitation. Second I like the Saturn for its heavy load capabilities. I'm still not sure I completely understand props. I'll call my dealer and see what I can get. Once the boats done I will post some performance numbers and if it plans on one engine(I'm more curious about this then anything else). I also plan on weighing the boat to get an idea of how much excess weight I have. Thanks again everyone. Cj
Peter	posted 01-10-2014 06:50 AM ET (US) Propellers are like shoes, you have to try them on to see what fits best.