Speed Test Again

Let me preface this with the declaration that Speed Tests in a boat are subject to so much variability as to be nearly useless.   Undaunted by this reality, we did one today to compare the old prop's performance to the new 5-blade prop's performance.

Whoa, back the boat up.   Today, Mark, my old college roommate, came up and hung out with us.   We started off with a lovely Mexi breakfast made by our glamourous Admiral/Chef, Karen.

Then we did chores as I needed to get a few things done, such as put the fuel additive in the fuel tanks (note, it takes a lot of additive to treat 1,500 gallons of diesel).   Then Mark and I hung the TV in the VIP room only to find out that the plug has no power!   Chasing that down is a task for another day.

It rained this morning but cleared off for a beautiful afternoon.   Not quite sunny, but still very pleasant.

So, on to our sea trial/speed test.   Basically, we note the current, speed and direction, then we go directly with or against the current and make a series of runs at various RPMs.   We increase RPM by 100 on each run and take a number of measurements such as: Speed over Ground (minus or plus the current), Engine Load, Gallons per Hour of fuel Consumption, Temperatures, Pressures, etc.   I distill that into a spreadsheet and then fight with Excel to generate some meaningful graphs.  I finally gave-up on making the graphs pretty as I was more interested in the data.

In a vain attempt to make this slightly more accurate, we would pause periodically to gauge the current speed and direction.

Apropos of nothing, we happened to drive over the spot where my folk's ashes were scattered, so we had a quick remembrance and tossed two flowers over to them.   I think they enjoyed our brief visit.  See the cover picture in today's blog.

Here's the raw data (note that the 4-blade prop data is historic as we only ran with the 5-blade prop today):

Here are a few graphs:

No surprise, the two props performed differently.   The surprising part was that even though the 5-blade prop had to run at a higher RPM to generate the same speed, the net fuel efficiency was about the same.  Hmmm.   Interesting, no?

I will have the new prop removed and retuned by the Mukilteo Prop Shop.   I hope they find this data helpful as they go through whatever calculations they do to figure out how to stop the singing and optimize the 5-blade prop's performance.

Regardless, the 5-blade prop was smooth as butter compared to the old 4-blade prop.   So, that was a big improvement right there.

One other issue I noted is that our main engine alternator wasn't putting out any amps.   Nothing.   I've got to check on that later this evening.   It may be as simple as a fuse...   Fingers crossed.

We returned from our outing and enjoyed a lovely diner of BBQ grilled Filet Mignon, Au Gratin Potatoes, Broccoli, and a Spring Salad.   Given the big meat, I selected a Long Cellars 2021 Denner (Merlot, Cab Franc, Cab Sauv, Carmenere, & Malbec blend sourced from Boushey Vineyards in WA).   Great wine!

Karen decided we needed ice-cream for dessert. Heedless of the 50-degree and falling temperatures, off we went to the Mad Hatter.   Just so you know, we all selected the teeny kid-sized scoop (and only one scoop each!).    My Huckleberry was really tasty.

Now, back to dish duty (that's one of my jobs), and then into the engine room to mess with the alternator.

Buenos Noches!