And here it is ....

First the diagram and the specs; in the follow up post the explanation and another diagram of the bar inside the mast and how the lines are run.

Click attachment above to view the system :

The first one is the system most often used on cats and typically still found on modern cats from the big builders. We all know this system.

The second drawing from the top is the AHPC Taipan 4.9 internal system. The bar holding the 4 wheels and the 3 wheeled block are inside the mast and the green line is lead out the mast through a 3rd exit block and than lead up to a single block on the luff of the sail. The end of the green line is then tied off to the mastbase or hooked on the mast below the gooseneck. Therefor this green line adds a 1:2 purchase to the 1:6 inside the mast totalling the 1:12 system. Notice how the line that held in the hand runs through all the block and corners in the mast. Often this line is some 4 - 5 mm or else you hands will really start hurting. This is a thick line that makes many many bends around the small block inside the mast

The third drawing is the system I composed some 18 months back unaware that some A-cat sailor were using this already. I think I am the one who introduced this system to the F16 though and others are copying it after I told them about it. I think AHPC is so as well. From the out side the system is identical to the second drawing and the old standard AHPC system. Only difference that can be seen is that the rivets holding up the internal bar are now found higher up the mast than with the standard system. This is not much of an issue as this was a custom manual job on each boat anyway. Apart from that all standard hardware can be used and older Taipans can be converted easily.

The trick revolved around three principles.

-1- reducing the number of bends a line has to make around the sheeve of a small block. Each turn induced friction and lowers the output of a purchase system

-2- Seperate the line one holds in the hand from the line in the remainder of the system. The first line (1st stage) needs a minimum diameter of some 5-6 mm to be able to pull comfortably on the downhaul. The other stages need small diameter line that are more flexible and lighterweight. In stage 2 (red lines) I used a very flexible 3 mm 300 kg dyneema line. This line is more flexible than the 3 mm 500 kg dyneema line I used in stage 3 (green line). Stage 2 only sees load of some 100-130 kg while stage 3 sees loads of 300 - 400 kg. Obviously the 3rd stage line is stressed highest. But up till now everything hold up nicely.

-3- I used large diameter sheaves, as you can see in the drawing, for the block in the first stage and also for the block in the sail. This will make the bend of the 6 mm 1st stage line less severe reducing drag still. For maximum laod baring capacity one wants 7 times the diameter of the line as the sheeve radius. 3 * 7 = 21 mm => 42 mm diameter sheeve => 30 mm sheeve approximates this closer than 20 m sheeve.

-4- For quick reaction of the system (accelleration) it is important that the first stage and less so the second stage as well are as lightweight as possible. I used very light 3 mm dyneema in the second stage but mostly because it was so flexible and the block inside my mast in the 2nd stage are only 20 mm sheeve blocks. However the biggest gain, I beleive, was made by using the extremely lightweight 6 mm swiftcord in the 1st stage (holding in your hand). This line weight next to nothing and is extremely flexible, 6 mm is very comfortable in your hand and the good grip lets you pull hard when need be and the line only costed 15 % more than the common used inflexible outermantle 4 mm dyneema line which is heavier as well.

Currently I very happy with the system.

I did put special care to tying the knots to the block to make sure the line are not cut by the sharp edges of the blocks. Next time I think I will sew in a thimble in the loop holding the 3rd stage line to the 2nd stage block. This point is highest loaded point in the system and I used a double threaded figure 8 knot with loop there. If anything breaks in my system then it will be here. Luckily this can break without me having to dismantle teh system to fix it. My base plate comes of easly and with a stick +hook I can pull the freehanging block out and retie the 3rd stage line that time with thimble. However I pulled the Bjesuz out of the system of couple of times now and it is still in one piece.

next post the explanations.

Wouter