How Fast?

9 years ago
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Westward
Westward
47 posts
47 posts
1 Aug 2016 7:35pm
Hi All,

I was wondering what speeds would be considered relitivly competative for a mini on wet(ish) sand. I see that people are quoteing between 50 and 60 mph but these seem to be on salt and clay.

I'm just interested to see if my creation is any where near competative? Having said that i expect a large chunk is down to the experiance of the pilot ;-)

All the best

Dave
lachlan3556
lachlan3556
VIC
1066 posts
VIC, 1066 posts
2 Aug 2016 10:45am
Pilot skill is a definitely a big factor. Its funny how good you get at keeping landyachts moving after a bit of experience.

I would say 30-40 kmh on sand would be average for me, but I haven't sailed on sand for years. In the same wind I'd be doing 50 - 60+ on clay...

Only guessing though
Bynorthsea
Bynorthsea
104 posts
104 posts
2 Aug 2016 3:48pm
I don't think you should be too concerned about top speed for a fun yacht, more important is the ability to get moving and keep moving in light winds. Mine is a heavy yacht designed for the beach, I need 15 mph+ to get going on sand with a 6m sail but in a good blow I top 30mph with a 3m sail. The beach I sail on is very variable with quite a lot of soft patches so I generally stick to big 20x12 wheels on the back. For a real comparison you need to sail alongside other yachts.
trbnt
trbnt
33 posts
33 posts
2 Aug 2016 7:33pm
I agree with the above- I would make sure you have the power to move the yacht in most conditions before looking to closely at top speed.

Soft sails are your friend...
Westward
Westward
47 posts
47 posts
3 Aug 2016 7:23pm
Hi Guys,

Thanks for the feed back. I'm intending on taking my mini along to some of the mini racing so was curious to know if my creation would be anywhere handy. I'd focused in more on speed for two reasons really:

1. Fast is exciting :-)
2. As descussed in my build thred the stering settup does scrub speed of in tacking and jibing so i figured strait line speed to be important for catching people up again.

I hit a top speed of 27 mph the other morning (aprox 43 kph) so that seems in line with what you guys have mentioned.

Bynorthsea,
Our beach sounds simillar to yours, we have a large chunk of clay and a wooden boat reck along with shifting patches of extreamly soft sand. Good fun dodging :-)

Regarding the point of "keeping it going" I am finding that it doesn't go to windward terrible well. Any ideas as to what this might be? I thought that it might be having to large of a sail (making me back off to avoid tipping over)

Thanks again for the comments :-)

All the best

Dave
trbnt
trbnt
33 posts
33 posts
4 Aug 2016 12:00am
Westward said..


Regarding the point of "keeping it going" I am finding that it doesn't go to windward terrible well. Any ideas as to what this might be? I thought that it might be having to large of a sail (making me back off to avoid tipping over)




The 'go' of windward ability is balancing act of sail form and power requirements where off angle forces provide diminishing returns.
The key players are aspect ratio, draft depth and location, area, and resistance to heeling moment.

One has to assess the present system to see if usable power is the limiting factor given the high known drags of beach sailing, or if the sail configuration limits how close the yacht will sail regardless of available power (wind speed).

I have limited experience in carts but tons of the aquatic variety.
In use of my recent build I did gather a few observations of windward limits in my case for beach sailing.
At my venue I found that power limits came into play far sooner than any configuration problems as the limit on how well I could make way to windward.
A 10^0 berm on one tack plus coming through the wind in soft sand made this a very power hungry proposition.
I was using a deep draft sail with low aspect ratio and did quite well for this type of use.
The high aspect sail I tried would point higher but lacked sufficient power to drive forward well given the draggy surface.
This sail was a re-cut but didn't have the draft as new to function well on sand.

For other venues with low rolling resistance I imagine that the high aspect ratio full roach platform will rule the day as the sail configuration will be the most important variable.
Hiko
Hiko
1229 posts
1229 posts
4 Aug 2016 11:10am
Westward
Sailing on sand is draggy at slow speed but the drag gets less as you gather more speed so it follows that the sail needs to be full for power getting started and then flatter for speed and pointing as the speed gathers
I have never tipped up going to windward fast but have had the front wheel lift off quite a few times tacking to windward around a mark when the yacht is going slower through the eye of the wind [more drag and the sail not sheeted in flat]
I have tipped up plenty of times at slow speed

Keeping momentum up is very important to these yachts you are more likely to tip at slow speed than fast in my experience
Try sheeting in harder and point up higher if you lift a wheel and you should go to windward better

A land yacht sailing fast is nearly always sailing to windward anyway due to the apparent wind moving to the front
The more you sail it the better you will get
Have Fun !
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