high altitude boating question - lake tahoe

J

joewall

New member
ahoy, c-brats! i'm back with a question after many moons of absence. i plan to take the betty louise up to lake tahoe next weekend. i am not planning on repropping or changing carb ports or jets. i believe tahoe is 6000 ft elevation. i am set up for sea level. i am running twin 40's, carbureated. my questions are:
1. am i insane to do this without making adjustments?
2. if i am, what do you recommend?
3. in know there are a number of you out this way (sonoma, ca) and am particularly interested in your experience with your boat when you bring it up to tahoe.

thanks, joedub
 
The obvious answer is to drop pitch of the prop. On our 22 we had a 17" pitch for sea level, 15" pitch for Powell, and 13" pitch for some of the New Mexico lakes where the previous owner boated.

The secondary answer is to put in high altitude jets in the carbs, if the prop doesn't do it. Leaning the mixture might help...
 
I have a 22 with a 90 etec injected and a 9.9 Johnson 4 stroke kicker. I have not been to Tahoe yet but have run several times at Eagle Lake (5100'). The etec runs and starts fine but I lose 4-500rpms, though I'm still within the operating range. It was also very cold both times (2 wks each) 30-40 degrees in the early am. I had a much more difficult time starting the carbureted kicker, but once started and warmed, it ran fine. I made no adjustments to fuel/air ratio on either.

I did go out and buy an aluminum spare with 3" lower pitch for future trips (including Tahoe) but I did not feel it was a necessity. I think you'll be marginally ok but expect close to 18% hp drop possibly more if not tuned for it. Just take it a little easier, don't lug it and take in the scenery. Just my guess.

You are starting with 10 less hp, are probably a little heavier and are 1100 feet higher (6225' rim on the web for Tahoe). Definitely, leave the water skis at home and, when you get back, relate your experience to the recent poster who wanted to know about a 60 hp for a 22.

Chris
 
I took Tortuga (a 22 Cruiser) up to Tahoe this summer. We have a Yamaha 90 EFI (new last year) and it did great with no adjustment or prop change. That said, I definitely noticed the difference -- probably a 20% power drop. We were able to tube with no problem (3 adults & 4 kids) but when we had 3 adults sitting in the back of the cockpit on a bench (water taxi style) we definitely bogged down.

So, I would think if you distributed the weight well you will have no problem.

We really had a great time

M
 
I have considered going to Tahoe myself. I have a few questions for those that have been.

Where do you launch? I am sure there are several places that would work. Also do you overnight on the boat? Anchored or can you overnight in a marina?

Any other information you want to provide would be welcome.

Thanks,
Steve
 
As far as I know, the only public ramp is Tahoe Keys Marina (http://www.tahoemarina.com/). It's $35 roundtrip plus an additional $30 (if I remember correctly) for an invasive mussel inspection. The mussel inspection is good for an entire year of launching if you get the boat tagged.

It was a nice marina -- though the ramp is small and I had a hell of a time getting the boat out due to the steel reinforced concrete being mostly steel grid (the concrete was eroded pretty good). Bring some mats that you can use for extra traction.

I leased a slip for a few days ($2.50 ft/ day). You can also anchor most anywhere on the lake where it is not expressly banned (again, I think), and there are several spots to get a mooring on a day by day basis.

A lot of good info online here:

http://www.tahoemarina.com/
http://www.aboutlaketahoe.com/beaches/m ... yConcierge
http://www.tahoesbest.com/Boating/
 
I know there are two launching facilities on the north end of the lake at or near the Ca./Nevada border. One is right next to the
Casino at Incline Village, and another at Sand Harbor a few miles down the Nevada side. Google the Incline Village Chamber of Commerce for further links and information on the first and....

Sand Harbor for the later.

Joe. :teeth :thup
 
thanks, folks! i broke down and ordered a set of props with reduced pitch. ouch! i'm going to be trolling with downriggers, so thought it best to be safe.

joedub
 
Joedub - My comments are more relevant for someone planning to buy new motors. Twin 50's wouldn't weigh more than the 40's, and if they were of EFI persuasion, your performance at altitude wouldn't be dramatically impacted. My first 22' had a Honda 90, and at close to 8,000 feet, getting on plane was difficult. My second 22' came with a 100 HP 2 stroke Merc, but I traded that in on a 115 EFI Merc, and run the same prop regardless of altitude. If you don't have trim tabs, you might consider adding those. John
 
I don't remember hearing the explanation here, so I'll drop in in for clarification:

Electronic Fuel Injected outboards do somewhat compensate for the altitude change when running above sea level.

They sense the decrease in atmospheric pressure, which also (and more importantly) is accompanied by a drop in the amount of oxygen available for burning fuel, and lean out the fuel mixture.

This results in a cleaner, more efficient fuel burn or combustion, and the motor runs smoother and doesn't load up like it would with fixed carburetor jets calibrated for sea level and "average" seal level pressure.

The EFI will not, however, compensate for the lack of oxygen available, and cannot make the engine develop the same horsepower it would at sea level; it just runs cleaner, more efficiently, and smoother, and without loading up.

To compensate for the loss of oxygen in the rarefied air, the only solution would be to compress the air, and this would require a supercharger or turbocharger, which is to my knowledge, only available on the larger Mercury Verado engines.

If one were racing, one could add nitrous oxide to get more oxygen, or go a step further and use a fuel mixture containing oxygenates, such as nitro-methane, but I imagine those steps used without a lot of judicious care would melt most aluminum alloy powerheads!

Joe. :teeth :thup
 
The boat launch at Sand Harbor is closed due to low water. The boat ramp at the CG Station just west of Tahoe City is opened but shallow. $30.00 for boat inspection and $10.00 to launch. No over night parking at the ramp.
If you come to this part of the lake, let me know I'll show you around. I live just above the CG Station and launch my 19 there all the time.
Call me at 530 412 2863.
 
We were at Tahoe for a few days in August. Our Honda 150 ran fine, but with a significant drop in power and rpms. It did not bother us. The ramp at the Coast Guard station at Tahoe City is a great facility with a great dock. While there is no parking overnight, there is an adjacent primitive campground where you can leave your vehicle and trailer for $15 per night. It was the safe/easy way to go. You make arrangements at the entrance booth for the ramp. As Steve said, they will do a $30 mussel inspection at the ramp -- a small price to pay to keep Tahoe free of invasive species for as long as possible. The Tahoe City docks are a short distance to your starboard as you leave the ramp. You can dock free for long enough to go to grocery stores, restaurants, etc., that are a short walk away. We stayed four nights in Emerald Bay. You can anchor or moor on a ball that goes with a boat-in campsite in the bay. We stayed for free on a first-come-first-serve ball across the bay from the campground. This ball is at the site of a sunken barge. We were not positive about the rules, but were told by two boaters that it was open to all and that there were no rules or local etiquettes. Hpe you have as great a time as we did.

Regards to all,

Greg
 
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