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2018 HCM 21' Granite - Jensen

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Re: 2018 HCM 21' Granite - Jensen

Postby Jaker » Thu Jul 12, 2018 4:09 pm

Nice looking ride Peter, let's meet at Buckskins again next year and run some comparisons! :Drink:

Congrats man!
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Re: 2018 HCM 21' Granite - Jensen

Postby viking » Sun Jul 22, 2018 11:00 pm

Assessment at Hagerman Reach, including the Meanchicken rapid, which is big enough to spit boats out backwards.

Relative to 22' Clusterweld which has 460 with Berkeley and Inducer, roughly 15 degree deadrise, variable to maybe 20 degrees where the bow starts to form, and wheel rather than stick. The important question is, "Is the new boat better than the old boat?"

1) HCM easily gets on step with 4 passengers and a half tank of gas. This would have been a struggle with the 460/Berkeley (one more passenger might have been a no-go).
2) Easily ran up Meanchicken with 4 passengers. With 460/Berkeley this might have worked half of the time, maybe.
3) On downrun of Meanchicken can turn HCM sideways and launch out of rapid between waves. With old boat, this really isn't possible because the sideways thing takes it off plane, so the subsequent "launch" is a dud. The HCM stays on plane at much lower speed, including when cornering.
4) Cavitation in white water is similar; the inducer definitely helps the Berkeley.
5) With the stick, it takes about 5 minutes of learning for reflexes to start kicking in. Reverse will take a bit longer, but this is more a Hamilton versus Berkeley reverse bucket thing, and not so much a stick steer thing. The stick is definitely better than a wheel. The stick is faster, but I don't think this is the whole story. The stick throw is short, so leverage isn't great, and consequently you can feel the stick pushing back. This gives immediate feedback about nozzle direction. The low leverage is not relevant because your arm is in a strong position to deal with it. (With a wheel and extended arm, the position is weak, so more total travel is needed for "easy" steering.)
6) HCM low speed handling is much better. This is partly because 212 has much better reverse, partly because a 212 has more thrust at idle, and partly because you can actually feel the nozzle direction through the stick.
7) The 212 can back off a beach where I would have had to climb out and push with a Berkeley (one old man is stronger than a Berkeley reverse).
8) The HCM has zero bow shear relative to old boat. "Anticipating the shear" is a deep habit that will take some time to kick.
9) Short bow and high helm mean much better visibility in new boat. With a side helm, visibility is actually better down the side, but overall is not as good.
10) Because the Clusterweld is variable deadrise and has a relative V-bow, I expected its ride would be smoother than the HCM. This isn't true. The "hull smoothness" is actually similar, but the new air-ride seat means the new ride is overall much smoother than the old ride.
11) Center helm makes it easier to line up when trailering.
12) New boat has 6'6" of standing headroom, so I don't have to stoop. Old people really like standing up straight.

The only real negative from the test run is occasional loss of 300-400 rpm off the top end. Outside air temperature exceeded 100 F, so this could be simply a heat issue. Once this is cleared up, there will be no negatives.
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Re: 2018 HCM 21' Granite - Jensen

Postby smitty » Mon Jul 23, 2018 9:59 am

Sounds good, this is about what I expected for assessment.

Note - (460 / Berk) my 20' with 4 adults, two kids, full tank - took a tiny bit longer to get up, but always did (on a calm lake... I absolutely would not load it that way on the river)

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Re: 2018 HCM 21' Granite - Jensen

Postby waylon » Mon Jul 23, 2018 7:59 pm

Well damn Viking if I knew this was your boat when I was over there this spring, I would have borrowed a die grinder and etched my name on her somewhere. Funny I spent a lot of time thinking someone knew exactly what they wanted in a build. :Drink:
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Re: 2018 HCM 21' Granite - Jensen

Postby viking » Tue Jul 24, 2018 8:53 am

Windows will be this weekend. Was waiting for some aluminum bracing for lexan.
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Re: 2018 HCM 21' Granite - Jensen

Postby smitty » Tue Jul 24, 2018 9:11 am

viking wrote:.... Old people really like standing up straight.
......



https://goo.gl/images/5hJanF

I just imagine I'm feeding my cat...
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Re: 2018 HCM 21' Granite - Jensen

Postby whee » Tue Jul 24, 2018 11:14 am

viking wrote:1) HCM easily gets on step with 4 passengers and a half tank of gas. This would have been a struggle with the 460/Berkeley (one more passenger might have been a no-go).
2) Easily ran up Meanchicken with 4 passengers. With 460/Berkeley this might have worked half of the time, maybe.


Question: Any exaggeration here or will a 22' boat with a Berkeley and 460 really not get on step with 5 pax? Or does it just take a really long time?
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Re: 2018 HCM 21' Granite - Jensen

Postby NoProplem » Tue Jul 24, 2018 12:18 pm

whee wrote:
viking wrote:1) HCM easily gets on step with 4 passengers and a half tank of gas. This would have been a struggle with the 460/Berkeley (one more passenger might have been a no-go).
2) Easily ran up Meanchicken with 4 passengers. With 460/Berkeley this might have worked half of the time, maybe.


Question: Any exaggeration here or will a 22' boat with a Berkeley and 460 really not get on step with 5 pax? Or does it just take a really long time?


I'm very curious to know as well. I have a 20' with Berkeley and a 351, it will get on step with 7 pax, 100 gallons of fuel and coolers/ gear. It takes 100 yards, but it will do it. I'm at nearly sea level so maybe I have an advantage there...
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Re: 2018 HCM 21' Granite - Jensen

Postby viking » Tue Jul 24, 2018 1:13 pm

Because I've never actually tested, I don't know exactly where the planing break point is, but at ~4,000 ft with 140 gal fuel, maybe 200 lbs gear, and a 200 lb driver, it struggles. Add one ~250 lb passenger, and it will get on plane maybe after forever. I didn't test with another ~250 lb passenger, but I'm fairly confident of a no-go. So assuming 6.2 lbs/gal fuel, an estimate of total load for no-go is 1770 lbs when distributed optimally.

So if instead we have 50 gallons fuel and 200 lbs gear, that leaves room for 1258 lbs of people. So 5 or 6 total, depending on mass. Little people are better. At sea level I'd get another ~300 rpm, which is a lot. At least one or two more people.

Also, my reference distance for "will it get on plane?" is relatively short. The boat must be able to come up one side of a rapid, pick a wave and slide across, fall partially off plane when reaching the opposite side, and then get back on plane to make the inevitable final climb that is maybe 100 ft ahead (or closer). If it takes 100 yards, then that's the same as "won't get on plane."

Also, the boat needs to get on plane when the river has a few degrees of uphill slope.

Anyway, that's the inexact answer. We might view it as "Conditionally won't get on plane."
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Re: 2018 HCM 21' Granite - Jensen

Postby NoProplem » Tue Jul 24, 2018 1:35 pm

Copy that, if we define getting on plane as "sometime today" then mine wouldn't lift that load either. Especially at 4000 feet. I know all the math, etc on HP loss at elevation, but real world experience shows me that I lose 600 rpm going from sea level to 4500 feet...and my boat is wimpy at 4500 feet.
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Re: 2018 HCM 21' Granite - Jensen

Postby Music Man » Tue Jul 24, 2018 1:52 pm

I just found out this weekend that my boat won't get on step with 30 60lb sacks of concrete and a full tank(135gal) of gas and 3 people and gear and food for 4 days. Didn't think it would when we loaded it, but had to try, long float trip down river to the cabin! :Drink:
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Re: 2018 HCM 21' Granite - Jensen

Postby whee » Tue Jul 24, 2018 10:17 pm

Thanks for the explanation Viking. Makes sense.
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Re: 2018 HCM 21' Granite - Jensen

Postby akhunter67 » Wed Jul 25, 2018 10:54 am

Music man do you have a lift , or did you guys walk that up the bank!?
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Re: 2018 HCM 21' Granite - Jensen

Postby Music Man » Wed Jul 25, 2018 12:49 pm

akhunter67 wrote:Music man do you have a lift , or did you guys walk that up the bank!?

6x6 Ranger just a little ways up river. :Drink:
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Re: 2018 HCM 21' Granite - Jensen

Postby viking » Sat Sep 22, 2018 10:14 am

The engine RPM loss has been eliminated via a new program from KEM.

Meanwhile, the trailer was making bald tires. The axles are implicated, so their manufacturer is being taken to task. Meanwhile, I received a replacement trailer with lots of free upgrades, delivered to Pittsburg landing while I was on the river, so all ended well (assuming new axles are good).
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