Hi
With the right materials I think I can make this boom , downhaul strong enough to pull 150 > 200 kg . ( Question : If I make it strong enough to pull 150>200 kg it will always pull this its fixed , I can not variate this . This is good when I need to close the sail to the max. but what if I need to open up the sail ? )
Iam thinking to use carbon tube instead of the Alluminium I use now for the boom it self . The white material need to be changed in to mylar with carbon fiber I think

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Why the white under the boom , 1st thing is to haul the boom down . The 2th thing why its there is It close the gap to the surface to make the sail go as low as possible .
3th thing ..... design , Iam planning to close the gap between the white under the boom and the numberplates . this will create one big white number plate where I can put my own stickers , sail number and stuff .
Have Fun ( I no Iam having it

)
Ruudje