Because most peoples have a problem with trans sounding names do they?
Why perpetuate these tropes?
Choosing the right performance cruising cat for Uhuru.
- Thread starter Mambo Kings
- Start date
Why perpetuate these tropes?
Proa sailors go both ways. It seems complicated but... once one lets go of pre-conceived notions about sailboats... it becomes 2nd nature.
he b gb
Anarchist
^ 
It gets worse….. Traditionally proas are called he’s, whereas most sailboats, monohulls at least, are generally referred to as she’s. I can’t bring myself to refer to my proa as a he, so I call it an it……
Two multihulls built out of paulownia or kiri:
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Sweare Deep
Member
Only if “most people” are bigots, but I have a greater faith in humanity and believe most people are way above such despicable, shameful thoughts.
I knew I should have used purple font………
Russell Brown
Super Anarchist
it's very tough to avoid getting in trouble with anything said about that thing you were saying.
Relax people!
Relax people!
Based on LOA, max Displ and SA working rig, I came up with the following indicative Base Speeds:
Outremer 51: ~11.3 knots
All the others, came out as ~10.9 knots.
I added the average payload of the others (~3.00 tonnes ) to the Slyder, because their website only gave lightship.
Just for fun, and because I have just today completed a similar exercise elsewhere, I ran some numbers. I have a fag packet methodology for predicting roughly what sized proa could carry that payload. Happy to regurgitate it here on SA again, or PM me if you prefer.
Bottom line is a ~68 ft proa can be the same Displ and payload as the Outremer and if you used the same white sail area, it would have a Base Speed of ~13.0 knots. A proa couldn’t carry that amount of sail, but reduced down from ~131m2 to ~85m2, which it could carry, you would have the same Base Speed as the original cat, and still be in credit for the weight, cost, handling, pitching, nose diving and drag savings on the reduced rig.
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Yet the Balance 526 just went head to head against the Outremer 51 in the Cape2Rio Race and finished 25 hours earlier sailing 250 miles farther to do so. This despite the Outremer being handicapped to win by 12 hours.
Both are pretty spectacular performance boats, but sometimes the numbers published are not the reality of how boats are capable of performing.
steelmadesteamer
Member
Sometimes there is also a non-digits-measurable factor present while "cruising-racing":
- if the Owner is willing or not to push his boat hard
- if the crew is able or not to push the boar hard
Yep there is a lot more to it than just numbers.Sometimes there is also a non-digits-measurable factor present while "cruising-racing":
- if the Owner is willing or not to push his boat hard
- if the crew is able or not to push the boar hard
Sometimes there is also a non-digits-measurable factor present while "cruising-racing":
- if the Owner is willing or not to push his boat hard
- if the crew is able or not to push the boar hard
Absolutely, sometimes the boat is not capable of being pushed as hard comfortably as other boats are. Sometimes what the manufacturer states as the displacement isn't actually the true displacement. It can also come down to technology aboard and load carrying capacity for a 3200-mile crossing.
Lots of factors.
Proafile - multihull design concepts and review
Proafile - multihull design concepts and review
proafile.com
S-number And Base Speed For Performance Evaluation
In the February/March 2011 issue of Professional Boatbuilder magazine, the ROVINGS section by Dan Spurr, there was a summary of a section of “The...
www.boatdesign.net
I use an older version, because it all can only be fag packet stuff in the absence of any other method and the differences aren’t great, so not worth the bother of updating my entire data base.
Where I can, I use info off rating sites, so you know it has been measured, and if you use rated sail areas, you can get sail areas which have been adjusted to reflect efficiency in the opinion of the rating rule used.
If you can get enough off plan info to input sail measurements, you can produce your own trial rating in OMR and Texel, not sure about MOCRA, and then you can compare with other known boats.
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My apologies.
The Base Speed numbers quoted upthread was for the Balance 482 only.
The Balance 526 comes out at 11.9 knots, so theoretically the fastest of them all.
Offshore racing for you. Even if it was the same boat.
So no point in spending silly amounts of money on a Potentially faster boat for cruising.
I would give up speed for some small comforts.
Being a cruising boat you can pick your weather and time.
A good boat well sailed and crewed any day over a fast boat.
Thanks for this update and clarification
The Balance is also the biggest out of the boats that you ran the numbers for.(For reference: Outremer 51, Balance 482 or 526, Slyder 49, C-Cat 48)
OK. Yes, I think such simple formulas are a sort of starting point. I think it can tell you if a boat is fast/slow/middle. And maybe when compared to similar boats of similar proportions.
But saying one boat is faster because one has a value of 11.3 and one is 10.9 is just nuts. I mean "misguided"
The formula ignores Cp, sectional area distribution, hull shape, RM, appendages, etc. and a host of other factors which all have a role in prediction of speed.
Base Speed = 1.7*(Lwl^0.5)*(SA^0.352)/((Disp*2240)^0.253) ?
Let's say a Tornado with 2 crew vs a Lagoon 380 light (published) displacement.
Well, they're just about even. Who would have thought.
Anybody want to bet who will wind around a race course in ANY sort of conditions?
But saying one boat is faster because one has a value of 11.3 and one is 10.9 is just nuts. I mean "misguided"
The formula ignores Cp, sectional area distribution, hull shape, RM, appendages, etc. and a host of other factors which all have a role in prediction of speed.
Base Speed = 1.7*(Lwl^0.5)*(SA^0.352)/((Disp*2240)^0.253) ?
Let's say a Tornado with 2 crew vs a Lagoon 380 light (published) displacement.
Well, they're just about even. Who would have thought.
Anybody want to bet who will wind around a race course in ANY sort of conditions?
| Tornado | Lagoon 380 | |
| LWL | 19.1 | 37 |
| SA | 236 | 829 |
| Disp | 0.317 | 7.145 |
| Base Speed | 9.66 | 9.51 |
Tell that to the administrators of Texel, OMR and MOCRA rating rules, because that is precisely what they do.But saying one boat is faster because one has a value of 11.3 and one is 10.9 is just nuts. I mean "misguided"
Looking at the race in question above, I can’t find the elapsed times for the two cats involved to work out what their average or Base Speed was for the race, to see if their elapsed time difference %age is similar to their Base Speed difference %age.
But you can turn it round the other way: If the race is ~ 3135nm long, then the theoretical time taken for the two cats mentioned would be ~263hrs (ie~10days 23hrs) and ~277hrs using their respective Base Speeds indicated above. That accounts for 14 hours difference straight away. Those Base Speeds are based on published numbers, not actual measured numbers, which could vary significantly and don’t include downwind sails and the extent of their use, which can vary enormously from boat to boat and race to race. If the race was ALL upwind, then the race is >4433nm long, and their times blow out to >373hrs (~15days 13hrs) and >392 hrs respectively, a >19hr difference.
What else would you recommend as a quick fag packet indicator, without going down the full measurement and calculation route? Happy to adopt it if you can.
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Hey I'm just pointing out that they might be useful as a rough indication but to think they can compare 2 pretty similar boats and say "that one is faster" isn't true.
I recommend that you take them for what they are worth. A rough indication, nothing more.
The fact that I could take 5 minutes and look at that base speed formula and cherry pick 2 boats that would give me similar base speed numbers suggests the formula leaves a bit to be desired.
Just looking at it I said "that gives too much credit to LWL and doesn't penalize displacement enough".
I recommend that you take them for what they are worth. A rough indication, nothing more.
The fact that I could take 5 minutes and look at that base speed formula and cherry pick 2 boats that would give me similar base speed numbers suggests the formula leaves a bit to be desired.
Just looking at it I said "that gives too much credit to LWL and doesn't penalize displacement enough".
