Double block for dinghy winching recommendation?

[demonboy]

I'm sat here (hundreds of) miles away from a chandlery and a (few miles away from my) tape measure, struggling to work out what double block would be suitable for my yet-to-be-made davitts. The davitts are specifically for hoisting the dinghy, nothing more, and I'm after small, inexpensive double blocks. I'm guessing I should be looking for blocks no larger than for an 8mm rope. I've no idea what size these are in the picture, but they're exactly what I'm after since our davitts are based on the same design:

The dinghy is 28kg and although I don't imagine hoisting with the engine attached, I guess I should factor that in. We have a 3hp 2 stroke Malta, so total weight not much more 40kg.

Can anyone help identify which model/size I should be researching? A lot of the online chandleries don't give overall measurements so a specific model number or a link to something like the above would be really helpful.

 

[Stork_III]

1xdouble + 1x double with becket. http://www.bartonmarine.com/products-size-1-blocks.asp

 

[Salty John]

Yes, a double and a double with becket: http://www.saltyjohn.co.uk/boat-rigging-blocks.htm

 

[rogerthebodger]

I have something similar that I raise my rigid dingy, 15hp outboard and my 2.3kva generator. I started with 6 mm line and blocks but soon increased them to 10mm line and 28mm blocks. I wish I had gone bigger with the blocks with the 10mm line.

 

[Stork_III]

Not sure I need the becket, which presumably also adds to the cost, but thanks for identifying the block size. Will investigate further.

Without the becket what are you going to tie the bitter end to?

 

[demonboy]

Without the becket what are you going to tie the bitter end to?

Yep, deleted post after realising this. Doh!