The Hexaratchet is the original ratcheting block (do sailnet site-search for: 'hexaratchet + 043').... the H7402 is the more modern carbo
-ratchet block but doesnt have a 'switch' to turn on/off the ratcheting feature. Both versions are similar in price. The friction release
value on each is: 10:1 on both .... meaning such blocks will hold 100 pounds of sheet force per 10 pounds of 'hand force' on the line
To make either of these styles work to maximum 'snub' you should at least have 180° of the sheave engaged with line
.... thats why the recommendation of having a hexaratchet or carbo-ratchet (H7402) at near the stern ... and the 'furtherest' block in the series 'away' from the furler
. Having the ratchet block 'behind you' and at the stern pretty much insures that at least half of the 'fluted' sheave is in contact with the control line
Where the hexartachet or carbo-ratchet REALLY comes in handy is when the jib
is already partly furled, its now blowing harder stink, and you dont want the extreme windloaded sail on the furler
to 'get away from you' and fully open by mistake; the ratcheting blocks with their 'fluted' sheave produce a LOT of friction on the line
... 10:1 in comparison to the strain that you put onto the 'tail end' of the rope .... a non-ratchet block has NO controlable friction (1:1) from the pressure that which you 'tail' (resist) the control line. Ratchet blocks have to be 'matched' to the exact diameter of the line you are using.
These blocks are not substitutes for cleats
... you will need either a cam cleat
or a horn cleat
to terminate the line.