On the question of upwind ability.  

Pointing ability is related to overall sailing efficiency.  Hull drag versus speed is the key factor in overall efficiency.  Length becomes an important factor in open water as boat pitching reduces efficiency.  High aspect rig and appendages are more efficient than low aspect elements.  Windage can also be significant.  Clearance of bridge or beams above water level is a feature for multihulls in open water.

I have read Cook’s Endeavour tacked through 160 degrees when first operated.  Safety is more  a function of seamanship in relation to the boat’s ability than just pointing ability.  A boat that cannot hold tacks less than 120 degrees apart is really going to be a motor sailor..   If the boat can motor under any conditions then sailing ability does not have much bearing on safety unless fuel runs out.

The pointing ability of a HP depends on many factors - I have listed most of them above.  A HP with a single mast relies on rudders for balance so their size plays a significant role in windward ability.  The most important factor in my experience on every sailing boat I have been involved with is hull cleanliness as the hull drag goes up rapidly with fouling and that causes a dramatic reduction in sailing efficiency.   You can spend a fortune on rigging and sails but a month of fouling will make that expenditure useless.

I did polars for Bucket List for my own interest - see attached.  It would have ability to still sail at 30 degrees to the true wind.  Best VMG was in the range 40 to 50 degrees depending on the wind strength.  The first polars are based on full sail with the assumption that it could be flattened/spill/partial luff and carried to high wind strength.  In reality it should be reefed above 15kts when on the wind but I wanted to see what the peak speed would be off the wind with full sail.  The polars with full sail shows best upwind VMG of 7.5kts.  The second set of polars shows the VMG increases to 9.1kts at higher wind with less sail area.  

I did not check for any rudder cavitation at high speed but that would be above 20kts and off the wind.  The pointing ability is limited by the rudders stalling.  I did not check if there is flow separation further back on the blades before stall.  That would be an issue for surface piercing blades.

Rick

On 25 Mar 2019, at 10:14 pm, '.' eruttan@yahoo.com [harryproa] <harryproa@yahoogroups.com.au> wrote:

Regarding sailing up wind.  
Is there a minimum that any boat should point to be safe?
Or is there an expected minimum?
How well can a HP point, and what increase and reduces this?