Ultimate Showdown of Ultimate Destiny: Harken Blocks vs. Ronstan Orbit Blocks

This year Ronstan released new smaller (20 and 30 mm) sizes of their Orbit blocks. They're pretty nifty blocks and as with any new introduction into the realm of marine hardware they beg the question - are they better? Our very own Rob Beach set about answering that question and came up with a whole bunch of numbers for us to crunch.

We set about comparing the new 20 and 30mm Orbit blocks with the comparable Harken and older Ronstan blocks. Basically we looked at two main categories - working loads and weights. Rob was very meticulous in his calculating and measuring, there were even spreadsheets involved. In the end we found that the numbers weren't as straight forward as we'd thought they would be and it was difficult to make direct comparisons but we've done our best.

Below is the working load data for the blocks. The main thing we found was that there appears to be no standard safety factor being applied by manufacturers to calculate their MWL (Max or safe working load). They vary from around to 2 to above 6 and it does seem to be the case that Harken's numbers are generally higher than Ronstan's. Even within manufacturers they don't appear to be standardized.

We calculated an average of all the safety factors and then used that to calculate an standardized MWL using the BL (breaking load) of the blocks. We felt this was the best way to compare strengths across the different blocks.

Manufacturer	Block	Sheave Diameter	Part #	BL #	MWL #	Manuf. Safety Factor	Max Work Load Safety Factor = 3.2203
20 mm Singles
Ronstan	NEW 20 mm Orbit; single lashing	20 mm	RF25109	1210	550	2.20	376
Ronstan	20 mm Single Loop Top	20 mm	RF20101	1210	550	2.20	376
Harken	Micro Single	22 mm	H224	1200	200	6.00	373
20 mm Doubles
Ronstan	20 mm Double	20 mm	RF20202	1540	770	2.00	478
Harken	Micro Double	22 mm	H226	1200	350	3.43	373
30 mm Singles
Ronstan	30 mm Single Swivel	30 mm	RF30100	1650	660	2.50	512
Ronstan	NEW 30 mm Single Swivel Orbit	30 mm	RF35100	1323	661	2.00	411
Harken	Bullet with Swivel	29 mm	H166	2000	300	6.67	621
Harken	29mm Carbo Single (w/ swivel)	29 mm	H340	1000	330	3.03	311
30 mm Doubles
Ronstan	30 mm Double	30 mm	RF30202	2090	880	2.38	649
Ronstan	NEW 30 mm Double Orbit	30 mm	RF35202	1984	992	2.00	616
Harken	Bullet Double	29 mm	H084	2000	400	5.00	621
Harken	29 mm Carbo Double	29 mm	H342	1625	660	2.46	505

We also looked at the weights of the blocks, both as stated by the manufacturer as well as our own measurements from our postal scale. For the most part they were the same but there were some small variations. We also calculated a strength to weight ratio in two ways. First we used the manufacturers stated MWL and weight and then we used our calculated MWL using the average safety factor and our own measured weight.

Manufacturer	Block	Sheave Diameter	Part #	Man. Listed weight	Strength to weight ratio based on man. data	Weight per postal scale	Strength to weight ratio	Man. Stated Max Diam. Rope
20mm Singles
Ronstan	20mm Orbit (Single Lashing)	20mm	RF25109	0.3	1833	0.3	1252	6mm (1/4")
Ronstan	20mm Single (Loop Top)	20mm	RF20101	0.5	1100	0.6	626	6mm (1/4")
Harken	Micro Single	22mm	H224	0.5	400	0.6	621	6mm (1/4")
20mm Doubles
Ronstan	20mm Double	20mm	RF20202	1.5	513	1.5	319	6mm (1/4")
Harken	Micro Double	22mm	H226	1.5	233	1.4	266	6mm (1/4")
30mm Singles
Ronstan	30mm Single Swivel	30mm	RF30100	1.2	550	1.2	427	8mm (5/16")
Ronstan	30mm Single Swivel Orbit	30mm	RF35100	1.1	601	1.2	342	8mm (5/16")
Harken	Bullet with Swivel	29mm	H166	1.75	171	1.5	414	8mm (5/16")
Harken	29mm Carbo Single (w/ swivel)	29mm	H340	0.9	367	0.9	345	8mm (5/16")
30mm Doubles
Ronstan	30mm Double	30mm	RF30202	2.8	314	2.6	250	8mm (5/16")
Ronstan	30mm Double Orbit	30mm	RF35202	1.7	584	1.8	342	8mm (5/16")
Harken	Bullet Double	29mm	H084	2.5	160	2.4	259	8mm (5/16")
Harken	29mm Carbo Double	29mm	H342	1.8	367	1.8	280	8mm (5/16")

So what does all this mean? Well, clearly the Ronstan safety factors are lower than those used by Harken. When we calculated the MWL based on our average safety factor this meant the Ronstan blocks generally saw their MWL reduced while the Harken's increased. This affected the strength to weight ratios in the same way.

Does this make the Harken's better? I don't really think so. The vast majority of dinghy applications see these blocks used at loads far below their MWL let alone their BL. If you are pushing the limits of the loads though, I think the data supports leaning towards the Harken products over the Ronstans.

There's also something to be said for the fact that the Ronstan blocks may just function at a higher percentage of their breaking load than the Harkens. Unfortunately I don't have the technology to test that in house - but if anyone wants to give me a load cell for free I'd gladly break some things.

The new Orbit blocks are definitely a new direction in block technology and it's great to see Ronstan pushing the boundaries of classic hardware. Using the soft loop attachments are a great idea and I think definitely something we'll see a lot more of in the next few years. They don't appear to offer the weight advantages you might expect though - the Harken blocks are the lightest in many of these categories.

If you were expected a "this is the best one" conclusion at the end of this post I'm afraid I'm going to disappoint you. I do think the 20 mm Orbit single is a pretty cool block - it's super lightweight and can be lashed anywhere you need it. I think the 29 mm Harken Carbo blocks are still a great choice for larger diameter lines. Beyond that there's no clear winner here. Each block has advantages and we didn't even cover pricing.