Plane-less in Tahoe

T

ThumbsUp

New member
Hello C-Brats!

I am the proud owner of a 22 Cruiser named 'Thumbs Up' that I purchased through an add placed on C-brats last year. I am excited to become a part of the C-Brat community and look forward to many great adventures on Lake Tahoe and the Pacific Northwest. Puget sound is on my list :D

My problem:

Yesterday I took Thumbs Up out for her maiden voyage on Lake Tahoe and the boat would not plane. I have twin Yamaha 50's with new props: 10 5/8 X 12. Boat was fully loaded with fuel, water, cooler, three adults and a kid. Should I drop prop pitch to 10? Yamaha doesn't make a 10 5/8 X 10 and the local Yamaha dealer suggested to have a local prop guy drop the pitch to a 10.

Does this boat have enough power for Tahoe? Was I carrying too much weight, fuel etc?

Mark :thup
 
Hi Mark,

Congrats on your new-to-you 22 :thup

Funny, but from the title I was at first thinking, "Gee, the guy has a new 22 and he's still complaining about not having an airplane as well" :crook

:mrgreen:

Twin 50's should be more than capable on your 22. Many folks have twin 40's or a single 75 and they are fine. You may need a slightly different prop at altitude (I have a separate one I used for Powell, which is at around 4,000' - the regular one did not give me enough RPM).

What you want to do is look up in the manual for your engines and see what the recommended wide-open throttle (WOT) RPM is. No matter how fast or slow you plan on cruising, you want to get the boat into the WOT RPM range stated, preferably in the upper half of the range. That way your boat is "geared" right at all RPM's, and the engine is running properly.

If you take your boat out now at your typical loading and your usual altitude, make a couple of runs at WOT (an "out" and a "back" just in case there is wind, etc. in one direction). Do this with both engines running together. Then, presuming you are not at rated WOT RPM's (I'm guessing you are going to be low) look to see what the size/pitch of your props is now and then contact a prop shop and see what they recommend. Other folks here who have run twins at altitude may also have some general size recommendations. However nothing beats running your own set-up at WOT, recording the RPM's, and taking it from there.

Sunbeam
 
You will have to reprop for the high altitude. We found the same situation with our CD-25 at Tahoe and Yellowstone. Twin 50s will move that boat just fine at sea level with the stock props. Might take a smaller prop to get full RPM at that elevation.
 
I think something else is not right besides correct sized props for altitude, though I agree for proper motor rpm you may have to drop a size or two in prop pitch. I currently run 12x10, but run very heavy at sea level & a good deal of the rest at 8000 ft Yellowstone Lake. For Lake Powell I'd be better off with 12x11 props. When we first purchased our 22CD with the twin Honda 40's it still had the original 11 5/8 x 13 props & at near 8000 feet Yellowstone Lake it would still plane with a medium load & good weight distribution. You have more hp, a pitch lower props & 2000 feet less altitude, so like I originally stated, something else isn't right to not be able to plane. Do you have trim tabs & are you using them along with your motor trim?

Jay
 
Welcome aboard!

One question, is how was the weight distributed? If you had the cooler, and two adults in the cockpit--that may be part of the problem. Any boat needs some weight up forward to get the boat up on a plane, especially if the prop is a bit off.

I suspect that you will drop the pitch down. I see that Yahama makes a 11 3/4" x 10--you don't have to stick with the 10 5/8 diameter which is on the boat now. I suspect it was set up for sea level. Quicksilver also makes props for the Yamaha which have 111/4 or 11 5/8 diameter x 10 pitch. There are others which are also amiable for those motors.

Props can be repitched--and a lot depends on the expertise of the technician who does the work. Today the computerized prop scan gives a very good picture of both the pitch of the prop, as well as the degree of cup and balance. All of those are important.

Take the boat for a spin with just yourself to start with--then add an adult and child--or whoever is best--with no other gear--and see how that works.

The boats really need trim tabs, and if you don't have them, I would suggest that as the first addition. Lenco electric are easiest to install. Bennetts are an excellent hydraulic tab.
 
Sunbeam you have me cracking up. Yes, I am plane less in Tahoe but not boat-less :lol: I will take your advice and make a couple of WOT runs with different loads.

Should have posted my comments on C-Brats before purchasing new props! The cost of the new props and the re-pitch will probably cost more than if I ordered the correct props to begin with. I just won't tell my wife :wink: New props are with the prop tech today. He is dropping the pitch to a ten and said we could drill holes and modify the cupping if necessary. He said the holes will allow more air bubbles to flow over the props. I don't know why this is important.


Thataway - love the name of your boat.

Most of the weight is at the stern. Full tanks of gas, cooler, two scotty downriggers. I store about 40 lbs of downrigger weight under the passenger seat. I should move the downrigger weights up front with the anchors and carry less weight. 40 lbs is too much.

Do you think a larger 11 inch prop with a 10 pitch would be better than the smaller 10 5/8 X 10? I don't mind buying a second set of props for Tahoe if it improves performance. Right now I am maxing at 4100 RPM with a full load and 10 5/8 X 12 props. Prop tech said I should gain 200 RPM's for 1 decrease in pitch. Looking at a 400 RPM gain going from 12 to 10.

Trim Tabs - This is my next investment and it sounds like Bennett trim tabs are the way to go. How do I find a good installer?

Will be making a Tahoe run this week and post my results. Really appreciate everyone's advice.

Mark :thup
 
ThumbsUp":34nzzarj said:
Trim Tabs - This is my next investment and it sounds like Bennett trim tabs are the way to go. How do I find a good installer?
Click to expand...

I debated back and forth between Lenco and Bennett before I got mine. When it came down to it, the only reason I was considering the Lenco was an easier install, and I knew I would only have to do that once, so I went with the Bennetts (this is not to say the Lenco aren't good, but just my own feeling which was that I really wanted the Bennetts, but sort of almost talked myself out of them because the Lenco install is a bit simpler -- they are electric vs. the Bennetts having hydraulic added to the install mix).

I installed mine myself, so can't make a specific recommendation, but I can say one thing I would insist on: That is that all the holes in the transom (which will all be below the waterline at some point; many all the time at rest) have generous amounts of core reamed out from around them, the holes filled with thickened epoxy, and then the (much smaller) real install holes be drilled only into the epoxy. This helps to protect the transom core from water ingress.

The more "standard" install is to just use caulk to "seal" the penetrations, or maybe, at best, to dip the screws in epoxy before screwing them into the core (IIRC the latter was in the Bennett instructions, which I did find slightly disappointing, as it makes it easier for people to show you that, "oh no, you are being too demanding/careful/worrying -- this is even how the instructions tell you to do it!").

The other thing I went back and forth on was the "indicator lights" for the tabs (at the helm). The standard Bennett switches are just two buttons, no lights. With the Bennetts, it's not that easy to go back and add the indicators later, so I sort of "had" to decide before I really used the tabs. I hemmed and hawed. They were expensive, and in a way I didn't really care what the tabs were doing, but what the boat was doing (tabs are just a means to an end). But.... I decided I would rather have them and find them superfluous than not have them and wish I did (or go back and add them!). Turns out I really like them. Not a life-and-death thing, of course, but nice. The buttons that come on the indicators are also slightly more pleasant to operate, for me. (However, I disconnected the "auto retract" feature as I didn't like listening to ten seconds of whiny tab retractor every time I shut the engine down - which was often to sit and drift peacefully.)

Will be interesting to hear what you get for RPM during your WOT tests.

Sunbeam
 
I suspect that you will do much better with the lower pitch props. You have a lot of slip, at 4100, and the 12" props. I suspect that you will have less slip, and actually will be closer to 5500 RPM, which is where you want to be.

Your prop tech is correct, and sounds as if he knows what he is doing. I have never had to drill holes in the props on the lower speed boats--I might try the props before drilling.--there are plugs which can be put in the holes if the prop does better without them, but they do create a slight amount of additional drag. The drilling of holes at precisely the right place does allow some controlled ventilation during the run up to plane, allows higher RPM, and more thrust as start up on a plane. But, only if done correctly.

There are other factors, such as engine being too deep in the water (common in C Dorys) which may prevent achieving top RPM. You are doing the correct things by moving necessary weight forward, and eliminating extra weight. The trim tabs will also help. It is possible that down the line you might want Permatrims, --foils which go on the antiventillation plate of the outboard. But hold off on those for now. Never tell your wife how much things on the boat cost! I learned this from my father early in life. He had a trick--pay half in cash, and a check for the rest. My mom only saw the checks! (They both went to their graves without sharing this--but I suspect that my mom knew!--She was a math major at Stanford in the 20's--and hard to slip anything by her. She was "just a house wife"--but made far more money working the stock market than my father ever did at his job.
 
Ok, I finally had a chance to take Thumbs Up to Tahoe last weekend and all I can say is……Woooooo Hoooooo, Yeeeeeee Hawwww... This baby cruises :D

The changes I made since the plane-less cruise:
-Moved 30 lbs of downrigger weights up front with the anchors
-emptied the water tank under the table
-ran with ½ tanks of gas
-new props repitched from 12 to 10

Both engines reached 5,000 to 5,400 RPM without any problems and we comfortable cruised at 16kts in choppy waters and 25kts in calm water with three adults and two kids.

Not only does she cruise, she turns heads :mrgreen:

Thataway - it's time to start bringing a little cash to the boat shop :wink:

Thank you C-Brats, you guys rock!

Mark :thup
 
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