1 - Can anyone share whether they recommend a Johnson 18 or a Thistle. Is it true that Johnson 18's are almost impossible to get, and if so, what boat comes closest to the Johnson 18 ? Also what are peoples thoughts on the Thistle, this seems to be more available than a Johnson 18 . I noticed the Portsmouth ratings on the Thistle is 83, and the Johnson 18 is 86.4. What does this difference of "3.4" translate to, faster by what ? The thistle looks like a GREAT boat - low portsmouth, availability for sale, can carry others, but can you single hand it too ?
2 - To that end, how can I translate Portsmouth ratings into a meaningful rule of thumb ? I know the lower the faster, but by how much?
3 - Does anyone know the fastest / lowest Portsmouth for a dinghy one can singlehand - I see the MC Scow is 87.8, while the Raider Turbo is 89.1. Both come recommended and are single handing capable. Again what is the significance of the rating differences. Here is a sample of portsmouth ratings for dinghies ascending:
Flying Dutchman (Int.) 80.1
Inland 20 Scow 83.4
M-20 Scow 83.5
Osprey Mk 2&3 84.8
Osprey Mk 1&2 85
14 (Int.) 85.3
Fireball (Int.) 85.6
470 (Int.) 86.3
Johnson 18 spi 86.4
Laser Vortex 86.8
Buccaneer 18' spi (SWN18) 86.9
Lightning (Int.) 87
Laser Stratos no trap 87.3
MC Scow 87.8
RS 200 Slp spi 88.3
Raider 2 Turbo 89.1
M Scow (M-16 Scow) 89.3
Alpha One 89.5
Flying Scot (19') 89.6
405 (Int.) 89.9
Finn (Int.) 90.1
Contender (Int.) 90.1
Precision 18.5 no spi 90.2
Celebrity w/Genoa 90.2
Albacore (15') 90.3
Vanguard 15 90.5
Laser (Int.) 91.1
Portsmouth handicap... Lower equals faster.
But remember, size=speed too. For example, a Highlander is a 20' boat, a Lightning is a 19 ft-er, so they are both faster & more powerful than most 15' boats... equipment also makes a difference. Some boats are noted to have spinnakers, some have trapeze. A 15 ft-er with a trapeze is going to be able outrun a bigger boat without, as soon as there is enough wind to make use of it.
The Portsmouth handicap in the US is under reported and not really all that accurate. Few clubs report data, I bet none have sent in times for the Johnson 18 in over 15 years. It would be a poor guide to pick a boat IMHO. The first selection criteria is what configuration of boat you want... centerboard, sloop or cat, spinnaker or not, trap or not, etc etc.
The Portsmouth handicap on the Jn-18 is particularly misleading, it is not a good light air boat and is a terrible 3-hand boat. I used to singlehand ours a lot but it's got a powerful rig that you rapidly start choking back when the wind gets up. In 10~12 with two average size people hiking there are not many centerboard dinghies that will keep up with it, we used to outrun Thistles handily and annoy the crap out of 505s, E-Scows, and a variety of beach cats. There are over a hundred out there, they occasionally turn up on Craigslist or Ebay so if that's really your pick (and it's not a bad one IMHO except that it's not good for 3 people unless one of them is an agile adventurous child) just keep your eyes open.
Below is adapted from a table of boat info
Flying Dutchman (Int.) 80.1 .... trap+spin, not recommended as a singlehander
Thistle 83 ....spin, difficult to rig & handle, not recommended as a singlehander
Inland 20 Scow 83.4 .... spin, possible singlehander
M-20 Scow 83.5 .... spin, possible singlehander
Highlander 84.3 .... spin, big for a singlehander but possible
29er 84.5 .... trap+spin, good singlehander skiff trainer but really for small people 2-up; 3 will sink it
Osprey Mk 2&3 84.8 .... ???
Osprey Mk 1&2 85 ....???
14 (Int.) 85.3.... trap+spin, not recommended as a singlehander except maybe for Superman
Fireball (Int.) 85.6.... trap X2 +spin, not recommended as a singlehander or for 3
470 (Int.) 86.3.... trap+spin, possible as a singlehander, difficult for 3
Johnson 18 spi 86.4 ......... spin, possible as a singlehander, difficult for 3
Y-Flyer 86.7......... spin, possible as a singlehander, possible for 3
Jollyboat 86.8... ???
Laser Vortex 86.8 .... ???
Buccaneer 18' spi (SWN18) 86.9 ........ spin, possible as a singlehander, probably pretty good for 3
Frontrunner 87 ... harder to find than a Jn-18
Lightning (Int.) 87 .... spin, big for a singlehander but possible, normally crewed by 3, can take 4~6
Korsar 87... ???
Laser Stratos no trap 87.3 ....???
MC Scow 87.8 ... normally a singlehander, can take 2
Tasar 88.2 ... normally 2, possible singlehander possible for 3,
RS 200 Slp spi 88.3 ... spi, normally 2, possible singlehander, possible for 3 if small
Raider 2 Turbo 89.1 ... spi, normally 2, possible singlehander, possible for 3 or 4
Interlake 89.1 ... spi, normally 2, possible singlehander, possible for 3 or 4
M Scow (M-16 Scow) 89.3 ... spi, normally 2, possible singlehander, possible for 3
Alpha One 89.5... ???
Windmill 89.5 ... possible singlehander, normally 2, difficult for 3
Flying Scot (19') 89.6 ... spi, normally 2, possible singlehander, possible for 3~8
405 (Int.) 89.9 .... smaller than a 29er
Finn (Int.) 90.1 ... singlehander, might try 2 but only with somebody you want to injure or scare
Contender (Int.) 90.1... singlehander, might try 2 but only with somebody with a high sense of adventure
Precision 18.5 no spi 90.2 ... spi?, normally 2, possible singlehander, possible for 3 or 4
Celebrity w/Genoa 90.2 ... spi?, normally 2, difficult singlehander, possible for 3 or 4, nice classic looking boat
Albacore (15') 90.3 ... no spi, normally 2, possible singlehander, possible for 3 or 4 if not large people
Vanguard 15 90.5... no spi, normally 2, possible singlehander, possible for 3
Laser (Int.) 91.1 ... you already know what one of these is