PH16/PH18 - minimizing weight, static/dynamic draft

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Jaysen
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Re: PH16/PH18 - minimizing weight, static/dynamic draft

Post by Jaysen »

fallguy1000 wrote: Thu Aug 19, 2021 9:55 am I tend to agree with Jaysen. I am surprised you didn't throw a vote for the LM18 as well.
If it were me... panga all day every day for nearshore. BFP (Big Forking Panga) for off shore offshore. They are well tested, lower power required, easily built, minimalist material hulls. BFP won't be cheap, but it will be fast, stable, and efficient. The weight distribution PangaRon is having is a common problem but that's something you have to address with any hull really (like, I don't know, when someone pulls 800lbs out of the arse end of a Helms 24).


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Re: PH16/PH18 - minimizing weight, static/dynamic draft

Post by TomW1 »

Guys RVC has already said that he already needs a larger boat than a LM18 and its 3 person capacity. So it is a no go. Agree the PH18 will be limited on the outside of the Keys to calm days only. But remember CL took his flat bottom OD18 everywhere . RVC the weight difference between the 60 and 70HP Yamaha outboards is only 6lbs.. These were a brand new design series about 5 years ago. The 50-70 are all off the same block. Hope that answers your weight question.

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Re: PH16/PH18 - minimizing weight, static/dynamic draft

Post by RVC »

Tom,

Your response answers two questions! No doubt the LM18 is a great boat. Also, I did not suspect the PH18 was only for calm days on the ocean side of the Keys so I need to cement this fact in my mind. I am not looking for something like the Panga. The news on the Yamaha outboards is new. I worked with them in 2017 so this is a big deal. I do not think Yamaha dependability can be beat. Obviously, my pdf of dated so I'll download a new one.

Many thanks everyone. This has been a useful learning experience. I will keep reading here. I thought I could treat my freshwater needs and saltwater desires with one boat...I guess not.

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Re: PH16/PH18 - minimizing weight, static/dynamic draft

Post by TomW1 »

RVC here are the data sheets of the 50-70 HP Yamaha's https://yamahaoutboards.com/en-us/home/ ... 0-hp/70-50 You will need to expand the info at the bottom and then look at each one separately. Tom
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Re: PH16/PH18 - minimizing weight, static/dynamic draft

Post by VT_Jeff »

TomW1 wrote: Thu Aug 19, 2021 4:41 pm RVC here are the data sheets of the 50-70 HP Yamaha's https://yamahaoutboards.com/en-us/home/ ... 0-hp/70-50 You will need to expand the info at the bottom and then look at each one separately. Tom
Kudos to he who can discern a difference between the 50 and 60 besides the listed Hp at 5500 RPM. Difference must be in the programming?
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Re: PH16/PH18 - minimizing weight, static/dynamic draft

Post by OrangeQuest »

VT_Jeff wrote: Thu Aug 19, 2021 5:12 pm Kudos to he who can discern a difference between the 50 and 60 besides the listed Hp at 5500 RPM. Difference must be in the programming?
They can also do a few things mechanically like the compression ratio or valve timing and duration. Change out throttle bodies so it will take more air and the 70HP states, "Combined with its 16-valve SOHC design and 17 percent larger intakes". That better breathing and little higher RPMs and the gear ratio at the prop could be the difference. I would think they measure rated HP at the prop shaft.

From what I have read, a few of the smaller engines that are only 5 or 10 HP difference, there is a plate under the throttle body that can be changed for a bigger one to increase HP.
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Re: PH16/PH18 - minimizing weight, static/dynamic draft

Post by RVC »

Yamaha has a nice smartphone app that allows you to record and download (?) datasets. It may be Android only but that makes no sense. I just own Android. We used it at the marina and it does work well. You have to purchase the dongle to connect to the harness. This may be a 'Service Tool' exclusively so it is possible it is off limits to the general public.

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Re: PH16/PH18 - minimizing weight, static/dynamic draft

Post by TomW1 »

OrangeQuest all good points. As far as the final gear ratio goes, it is 1.85 for the 50 and 60 and 2.33 for the 70HP allowing it to run a larger pitched prop for more speed. The NMMA requires HP be measured at the prop shaft. RVC those data downloads are for dealers only, all of the manufacturers have them. They can tell the dealer everything that has happened and are in a series of code that need to be interpreted.

Well that is it for tonight.

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

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Re: PH16/PH18 - minimizing weight, static/dynamic draft

Post by jonnymac »

in high school we took took a family vacation to big pine key and camped for a week. it was awesome. one day we rented a boat, I’m not sure the model or hp. It definately had more of a deep V than the ph16/18. It was an 18 ft boat. My dad asked them do we need to fill up at lunch or anything. the guy said you won’t run out of gas. Ok. off we go we drove that thing all over on the gulf side, had to put the motor up a few times and push it hundreds of yards to get out of the skinny water, just had a blast. then we get the great idea to go on the ocean side, I look at the crappy fish finder find a way over to the ocean side and it was fine just riding along much slower. the. we go to head back a different chanel than we came out, and next thing we know its like 3-4 ft swells, we are going just about hull speed as my inexperienced dad is trying not to stuff us in to the backside of a wave which we did take water over the bow a few times. then we get back to the rental dock and the guy goes to put gas in it and it was pretty much empty. The boat didn’t have a gas guage so we had no idea what actual fuel level was.

long story short, in my experience its two different boats to consistanely go on gulf and ocean sides of the keys

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