Prop/WOT/engine height - would appreciate your thoughts.

[Sunbeam]

Did you use the storage facility in Big Water? They can get a UPS package for you. They did it for me.

As it happens, I called them earlier this afternoon, they said no problem, and so with any luck the prop should be winging its way there now. I'm pretty jazzed that they just offered to send it for me to try (without my asking).

(I did store the boat at Big Water last spring - at the time I mentioned that you had recommended them and they said "Oh, we thought of him when we saw your boat since it's the same kind." Good folks and I appreciated the recommendation from you.)

I'll have to report back after I get some data with the various props (and not changing other variables). I always enjoy an experiment

 

[Sunbeam]

I got in touch with the prop shop where I bought my current prop....he suggested I try the 13.75" x 13 pitch 3-bladed, and he said why didn't he ship it to me at Powell, I try it, and if it worked well I send him some money, and if not I send him the prop back. I can't exactly argue with that kind of service :thup

Just thought I would update this. I started out on Powell with the aluminum, Solas 4-bladed prop I put on when I got the boat (13.25" diameter x 13 pitch). I wasn't thrilled with the performance near sea level (why I started this thread), but I wanted to keep it on to provide some comparative data at Powell. Also, this prop (or at least I thought it might be the prop) gave me an annoying "sing" at a useful speed (from just above idle forward through to where I was making a small wake).

So, did a few WOT runs on Powell reasonably heavily loaded, with the latter (4-bladed) prop: WOT was 5,100 rpm (recommended range 5,000 - 6,000) with a speed of about 20.5 knots. So running at about 80% put us at 4,100 rpm, and around 13.8 knots. 3,800 rpm gave about 12 knots. Not horrible but I was hoping it could be better - especially the WOT rpm. No desire to lug the engine.

So, time to try the new 3-bladed prop the fellow at the prop shop sent me to try out. It's an aluminum Solas, 13.75" x 13 pitch, 3-bladed. It made a noticeable difference in a few ways. First of all it sounds a bit different (at all speeds). Maybe a bit lower and "huskier." I find it more pleasant to listen to. Second, the "sing" is very much reduced. There is none at creeping along speed, and just a touch at around 1,100 rpm. Best of all, I can speed it up to maximum no-wake speed and that level does not have a sing (at least at Powell elevation). So the "sing" is easy to avoid, which wasn't the case with the other prop.

Moving along, it seemed a bit slower to pop up on plane, but not in a problematic way. Just a slight difference (this makes sense, as that is supposed to be one advantage of a 4-bladed prop).

Next, I brought it up to WOT. This prop got the boat up to 5,500 rpm. Maybe not the ultimate, but solidly in the middle of the recommended range. Interestingly, speed was around 21.7 knots (I thought maybe there would be a decrease rather than a slight increase). Again the timbre of the engine was more pleasant. Now 80% throttle was around 4,400 rpm and produced around 14.9 knots. Overall, the boat just seemed happier with this prop (and the figures seem to support that). I'm thinking it's a "Powell prop" though - likely not for sea level or lightly-loaded use.

Next up is to try the prop that came on the boat (13.5" x 15 pitch, 3-bladed aluminum). It's got a couple of dings, so I had relegated it to spare duty after the initial sea trial (where it did give 5,600 rpm/28 knots at sea level with a very light boat). But I do like a controlled experiment. My guess is that this might be the best size for "normal" elevations. If so, I think I'll see if I can trade in the 4-blader on a new version of this size. Need to do a few tests first though (and I have not addressed engine height at all, but at least I'm comparing all the props at the same height).

I have found that keeping the engine trimmed all the way down is the most efficient, and also that when I trim it up it gets louder and just sounds less pleasant; but that might change with a change in engine height (?). I've also found that somewhere around 1/3 to 1/2 tabs are the best (at least at Powell). Any more tab and the bow tends to feel "draggy"; less and the bow is higher and harder to see over, plus speed drops a touch (maybe .3 knot). I imagine I'll be able to fine tune these types of things as I get more used to the boat (and at different locations/conditions).

Hopefully not too long and boring, but I wanted to follow up (don't you hate it when you search at some later date, find a thread that is talking about just the subject you are interested in, and then it just peters out and you never find out "what happened"? :? )

 

[thataway]

No surprises here. very heavily loaded you may have been able to run an 11" pitch (your 7500 foot elevation prop--think Yellowstone or Tahoe).

I guess being an old guy I have never been concerned with sounds of a prop. Was the fully trimmed down motor and 1/3 to 1/2 trim tabs the most efficient speed? If you were running in following seas--(which you would rarely get at Powell), the running bow down might not be a good idea.

Also the Permatrim helps with getting the bow down--if necessary but you don't want it trimmed that way if the Permatrim is on, for down wave use.

 

[ghone]

Hi Sunbeam. Missed this before. As we're pretty heavy, I find the 13 1/4 x 15 3 blade being a good fit. I run 5800-5900 wot and trimmed well when in flat water on the coast. I don't have Permatrim or any foils on the motor. I do have Bennett tabs. For wot I had the throttle at full open and then played with tabs and engine trim until I saw the highest rpm and speeds. At Powell we ran 5400 +- in flat water. Most of the time on Powell was 6 knots however. We ran quick just to see. We are spending much of our time in displacement mode with higher speeds for getting in prior to happy hour or crossing large bodies of quickly changing waters, ie Georgia and Haro straits.
I am happy with this prop for elevations up to Powell. Higher we'll need a 13 1/4 x 11. I carry my original 13 1/2 x17 for a spare. Only good on a light boat. I would likely see about 5200 ish at sea level with this one. No hammer aboard. Just a spare prop. Both being aluminum. Wreck it and I need to find a rock to use on straitening blades! I prefer bent blades to bent drive train so use aluminum props.
As an aside on the noise issue, as I wear hearing aids and Carolyn has outstanding hearing, when it comes time for high speed runs, we pop on the Bose noise cancelling headsets. These plug into IPad or phone for in flight music and also have a jack for VHF so I can talk on the radio even at speed. I have felt the boats are fairly noisy at full song, but maybe I'm easily fatigued thru impaired hearing. Bose is worth the money. I sometimes think the battery has quit so take them off to see, now it's loud!!
Best of luck. George

 

[Sunbeam]

Hi Sunbeam. Missed this before.

Hi George,

Glad to see you comment as I had noticed (I thought?) that you had bought a 13 pitch prop to try for Powell, but then I didn't see (or maybe missed) how it ever worked out.

As we're pretty heavy, I find the 13 1/4 x 15 3 blade being a good fit. I run 5800-5900 wot and trimmed well when in flat water on the coast. I don't have Permatrim or any foils on the motor. I do have Bennett tabs. For wot I had the throttle at full open and then played with tabs and engine trim until I saw the highest rpm and speeds.

At this point I'm thinking that prop might work best for me too (near sea level). I never really tried it (except super light at sea trial) because it was not in great shape and I went to a 4-blade when I bought a new one for normal use. I'm going to re-try the original one and if it works well (as I suspect it might), I'll see if I can trade in the 4-blader on a new one (aluminum).

At Powell we ran 5400 +- in flat water.

Was this with the 15 pitch? Or the 13 pitch I think I read you bought for Powell?

I am happy with this prop for elevations up to Powell. Higher we'll need a 13 1/4 x 11.

Here I'm confused as there is a gap (13 pitch). But maybe it's a typo, or...?

No hammer aboard. Just a spare prop. Both being aluminum. Wreck it and I need to find a rock to use on straitening blades! I prefer bent blades to bent drive train so use aluminum props.

My hammer ultimately did not make the cut either. But then (due to the extra one for a trial) I have three props aboard! (And there are plenty of rocks around.) Maybe when I'm down to two I'll reload the hammer

As an aside on the noise issue, as I wear hearing aids and Carolyn has outstanding hearing, when it comes time for high speed runs, we pop on the Bose noise cancelling headsets.

I'm glad you mentioned these - I'll have to look into them. I've been wearing either a pair of 3M "regular" earmuffs, or foam earplugs, or both. The main problem I'm having is that they then press the earpieces of my sunglasses into my head which really hurts after a while. Maybe I'll have to modify a pair of sunglasses to hook onto the earmuffs without going behind my ears. I'm also not thrilled with this particular set of earmuffs, so I'll look into what you have (mine are just passive).

I have felt the boats are fairly noisy at full song, but maybe I'm easily fatigued thru impaired hearing.

I think I have pretty good hearing and I dislike the noise too. But then I'm used to that moment where you turn the engine off and raise sail, so perhaps I'm spoiled (on the other hand, I'm sure enjoying the things the 22 can do that some of my past boats could not, so it's not a lack of enthusiasm but just a notation).

Sunbeam

PS: Back to the prop/Permatrim: I don't know what the engine was like without the Permatrim (only ran it once on sea trial), so maybe it's improving things in just the fully trimmed down position; however, I find I can "never" trim the engine up and have any positive result. It always just makes it much noisier and a bit slower. That makes me wonder if others do find that adjusting the trim with the Permatrim does good things. If so, maybe it's back to the "too low" motor possibility.

 

[ghone]

Hi Sunbeam. The 13 1/4x15 works fine on Powell. Runs 5300-5400 wot. I use it here on the coast also. For much higher I'd just go to 13 pitch. Leave the diameter about the same We find we don't blast around at wot much. Cheers George

 

[Sunbeam]

Thanks for the confirmation, George. Will be interesting to see what I get at WOT (with the boat loaded vs. super light). Maybe the 15 pitch 3-bladed prop would be fine for all situations - I'll find out when I try it. Doesn't seem like the 4-bladed one I have is going to be the best for anything (oops). Meanwhile the 3-bladed 13 pitch I have on loan has worked well on Powell (5500 WOT loaded but with some supplies used up so maybe 80% of original load).

I never cruise at WOT, but my understanding is that being able to attain an RPM in the WOT range (and preferably higher in the range) means one isn't lugging the engine at other speeds, so is desirable no matter how fast one cruises. For normal "going fast," I've been limiting my RPM to 80% of WOT. But this is all amateur knowledge/reading on my part (and don't ask me about docking, ha ha). Going slowly is nice (and quieter!).

 

[thataway]

My reason with for the Permatrim is to get the bow down more for really rough stuff. It does provide some lift for the stern on getting up onto plane.

It sounds as if you are running your boat a bit more bow down than I do, but without seeing it in person it is difficult to know.

Engine height will make a difference.

 

[Sunbeam]

Thanks for the confirmation, George. Will be interesting to see what I get at WOT (with the boat loaded vs. super light). Maybe the 15 pitch 3-bladed prop would be fine for all situations - I'll find out when I try it.

Well, I tried it today, back-to-back with my new-on-loan "Powell prop." So, same conditions, same boat load. This is on Powell with a light-for-cruising 22. i.e. virtually empty water tanks, about 15 gallons of fuel, no food (well, we still had the twelve olives we subsequently ate for lunch :wink). Of course we still had our "stuff" aboard (but we did make an effort to lighten the boat before launching), and we had about 5 gallons of cold melt water in the cooler. Can you tell we were on the way to the ramp to take out?

So the prop I put on to try today was an aluminum 3-bladed Michigan Wheel of 13.5" x 15 pitch that came with the boat. It's got a nick here and there, so is my spare, but I wanted to try the size. It didn't work out very well for Powell (elevation ~3600 feet), because with it my WOT was only 4800 RPM (minimum recommended is 5000, and close to 6000 would be better). Top speed, at 19.7 knots was slightly less than the "Powell prop." It did not "sing" at any speed, which was nice (and proved it's nothing on my engine, but rather the different props). I went right back to the beach and changed back to the Powell prop.

Five minutes later with the Powell prop back on (3-bladed aluminum Solas 13.75" x 13 pitch on loan to me to try out) I was back up to 5400 RPM and close to 21 knots. I think that's a keeper and will stay my Powell prop. I'll have to re-try the original at sea level (which did give me 5600 RPM and 28 knots at sea trial originally).

I still think I can probably work with the engine height to improve things (or maybe a transom wedge?). Right now it is virtually always more efficient to have the engine trimmed all the way down, so in other words, there is no "adjustment" I can make with the Perma Trim. The only time I have found trimming the engine up to change anything for the better is at no-wake speed, when raising it increased my speed slightly. All other times it just makes the boat louder and reduces speed (for a given RPM). This doesn't seem like how it should be, so I'll delve into it - probably raising the engine like Roy & Dixie did (same engine, same dealer install). But for now I was able to try all three props under "same" conditions, so at least the info was comparatively useful.

Sunbeam