Rubber Donuts

I first saw the thump mats a couple of weeks ago when viewing photo-media of a time period Bristol Channel Cutter that had been restored. They are certainly an interesting alternative to the rubber donuts, and I would assume more authentic to the time period. That’s a guess mind you, as I haven’t conducted any research as to the actual origin of the mats.

During my research for Zygote’s word list, the earliest usage of the term “thump mat” is Ashley in 1944. Doesn’t mean the term wasn’t used before, but I could not find an older example.

R H Dana, The Seaman’s Friend, from 1841 is a reliable reference for detail. Dana mentions mats used to prevent chafe. But not bangs and thumps. He wrote than an ordinary seaman should be able to plait a sennit and that a boy should learn how to make a sennit. Dana has instructions (and a diagram) for making a Turk’s Head (cylindrical one, not a flat mat), but doesn’t refer to a simpler mat. Curious. But perhaps all seamen and boys could make a flat knot mat without thinking about it.

We all lack curiosity about the mundane, what we all take for granted. That’s part of why I’ve lost count of the hours I’ve spent researching things like a joker valve (earliest reference I’ve found is in 1955. Plenty of speculation about the origin of the term, but I reckon the last person who knew - likely the person who formalised the term - died in 1982). Or a “Swedish” fid: I’ve tried four of my contacts in Sweden, but neither they nor I can find the full name of the 1953 inventor on record, an otherwise anonymous A. J. Svenson, lost in a heaving sea of Svenssons and Svensons. Same goes for what I now know is a ‘counter seat’, which previously I thought was a ‘trolley seat’ (and it seems they were both in some cities).

Thump mats are clearly aboard some classic boats, e.g. superyacht Shenandoah (hull dates from 1902, extensive refit in 2009) click here to see one of her thump mats:

I like the spring stand-ups Davey sells. But I’m not moved to buy. Yet.

As well as thump mats, we tried gluing pads (only about 1" diameter, about 4 mm thick) of rubber on Z’s staysail turning blocks. Dulls the bang, turning it into a thump, about the same effect as a thump mat (but more discrete). Anything is better than the bang of a naked block hammering on the handrail!


The proper tool is called a pin spanner. Park Tool Company makes three pin spanners for bicycles. Crank & Bottom Bracket | Park Tool. The difference in size is based on the diameter of the pins.

McMaster-Carr also sells pin spanners.


McMaster-Carr also sells pin spanners.

Wah! Nicely priced by McMaster-Carr.

Excellent catch on terminology, Rod! Well done.

I’ve added it to Z’s word list (next version still unlikely to be uploaded until late July). ‘Pin spanner’ is not in the OED. First clear use, that I found, of the term in print was in 1887.


Shaula has several thump mats, under blocks and other places. They are very easy to make if you can do a 3 strand braid–like is used on hair. They can be flattened to form a mat, or formed around a cylinder like tubing etc.

Take a line, coil it 3 times, and start braiding. Keep pulling the line through to maintain the 3 strand braid. When you have as many braids as you want, pull the long end back through what you’ve done, doubling or tripling the braid. To finish up, whip the ends and tie them together underneath.

I’m sure Ashley has lots of more complicated mats, but these are very easy to make–maybe 15 or 20 minutes and they look good on BCCs and do the job.
Dan Shaula

FSE Spunflex is great for making mats and rope rings. It’s inexpensive and available from ALLen C Rawl, LLC


Here’s another take on thump mats…

Well, not to be critical (because we all have different tastes), but …

beautiful, traditional boat (wood blocks, lots of bronze, including the pushpit!!! man, I like that) … I just don’t think those thump mats do that boat justice!


I couldn’t agree more, they look like they belong on a modern production boat. The picture I posted is a Lyle Hess designed 34’ Falmouth Cutter that was brought to life by Channel Cutter Yachts. She is truly a work of art and a thing of beauty, and definitely more deserving of a traditional mat.


The rubber donut installation went great thanks to your help! I ordered the following Davey & Company teak block as a spare -

Length 4 1/8" (105mm)
Rope Size 11/16" (18mm)
Sheave 2.17" (55mmx20mm)
Work Load 4840lbs (2200kg)

I’ll let you know the quality compared to the ABI blocks once I receive it…