Saturday, May 2, 2020

A New Toy--Holdpeak Anemometer

It never fails to amaze me how instrumentation has come down in price. From lab equipment to non-destructive testing instruments, the change is not quite as dramatic as consumer elelctronics, but it's nice.

My pricey circa 1990 anemometer finally caved in, I needed one for an upcoming article on boat ventilation, and I braced myself for the expence. And it was... $25 through Amazon with free delivery.

I had to add a few slips of tape to the blades to perfect the balance; out of the box it was a little unstable below ~ 0.4 knots. Properly balanced, it is stable and accurate down to 0.1 knots, which is to say, absolutely amazing for so little money. I swear, it spins when a bug flies by.

As far as sailing goes, it's not a substitute for a masthead instrument. You don't get direction, it doesn't interface with the autopilot, and deck level winds are always influenced by rigging and sails. But I actually wanted it for local readings, and should I want to extend it aloft, it has min and max recording and can be attached to an extension via a 1/4" USS mounting thread.

Already a few new projects have suggested themselves. I wouldn't call it industrial duty, but it works.


  1. Can't wait for this. Which magazine is this going to be in? I had a similar idea about a year ago, and recently looking at the derelict "free" boat in my yard (it's trailer is much lower than the current one I have for my Rl24) I was about to go down this same path to figure out just how much airflow will dorado vents, mushroom vents, powered vents have and are they enough for the cabin volume per hour everyone quotes. But now my favorite trusted expert is doing it so I can chainsaw this eyesore and haul it to the dump.

  2. Practical Sailor Magazine.

    I'm not finished, but let me offer these cheats:

    * Location matters more than size or brand. Low profile vents in high pressure (stagnant) locations can drop as low as zero flow.
    * Cowl vents do very, very little when facing the wrong way, and the wind is always the wrong way at the dock. It is a myth that a reversed cowl somehow "pulls" air out; it just functions as a hole.

    Cowl vents serve a purpose underway in rough weather , but mostly, they were what we had before electricity and solar vents were invented.