A friend of mine has a 21 foot fiber boat and we where thinking of fixing it up
does anyone have any suggestions as regards the best way to build a tuna tower
and also we where thinking of running a direct drive and a z drive or shall we do 2 direct drives
We've briefly spoken about this, I don't believe in direct and Z, its a combination that i have NEVER seen used by any manufacturer. It's not just about sticking a hole in a boat, but drag,the way you effect the hull dynamics etc. Mixing is very much a home built thing, and I would try and get some proper information from home boat building forums etc.
You're better off going with a single direct drive (or shaft) and maybe having a smaller wing engine also on a shaft, which might run a fridge/freezer and then act as a get me home engine in case of problems.
What are you trying to achieve mixing a shaft and a Z drive. Both would need to be mounted along the centre line, I have never seen a Z drive offset Port or Starboard on a single installation. You would have performance issues, manufacturers always try to get the thrust as close to the centre line as possible, especially in twin installs.
On the Tuna Tower, have a look at home ppl like http://www.cfab.com/ who seem to be the No. 1 Tower maker.
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