Boat speed

[Sabre27Admin]

bob shaw
United Kingdom
7 Posts

Posted - 12/06/2011 : 10:07:55
I am usually a potterer but I went out in 20 knots on Saturday with the deliberate intention of 'pushing' Moonflower. She was rerigged this winter and I wanted to give the wire a good stretch. On a beat I got 6.3 kts through the water. She is fin keeled with 10 year old sails. My question is how much improvement can I expect when I eventually replace the sails?
sabre27
178 Posts

Posted - 12/06/2011 : 23:50:50
Hi Bob,

6.3kts is a respectable speed close hauled, but I would guess that you were sailing in the shelterd waters of Weymouth bay, so it difficult to make a judgment from just the written word.

My 'new' Kemp sails are more than 10 yrs old and are just the same as when they were new, as far as I can judge.

Perhaps we can sail together one day soon, Corsair is just up the coast in Poole and is in need of some miles this year! You will beat me as Corsair is a twin.

Paul Howard. S27OA Technical Officer.

bob shaw
United Kingdom
7 Posts

Posted - 13/06/2011 : 19:38:58

No Paul you will beat me, I'm not a very good sailor

dave
United Kingdom
67 Posts

Posted - 13/06/2011 : 20:31:13 Show Profile Email Poster Edit Reply Send dave an AOL message Reply with Quote View user's IP address Delete Reply
my best is 9.5knots but we had 2 knots of tide under us plus 20+ knots of wind it was some sail we had to reduce sail as we would have got home to early to cross the mud to my mooring

2E0YFO
United Kingdom
21 Posts

Posted - 16/06/2011 : 18:10:24
my best speeds so far... on the sea, with approx 6ish knots tide, 15mph reletive land speed, so I'm guessing thats about 8-ish knots with a fair wind. On enclosed water 7.5 knots very close to the wind and just under at about 270 degree from my heading with 20-25 mph blow. This is with a bilge keeler! I have no idea how old the sails are, but are very little used!

I have been refered to as mad... speed is not a guage of how good a salor you are, a good salor is measured by how you handle a catastophy!!

Malc.

boat:- hole in water you pour money into!

Latrigg. '89.

sabre27
178 Posts

Posted - 16/06/2011 : 23:40:19
I smell the distinct whiff of 'Fishermans tales' here chaps. Let's not get carried away!

Anyone got an accurate 'through the water' log on their twin keeled Sabre? I have and it rarely goes over 6kts to windward except in my head! There again, Corsair probably displaces 3.5 tons or more!

Paul Howard. S27OA Technical Officer.

Peter OD
United Kingdom
50 Posts

Posted - 17/06/2011 : 00:01:34
Shouldn't max speed be close to 1.34 x sq.rt. of waterline length unless the boat is planing, which I would have trouble believing! That would give max. 6.5 knots assuming heel increasing waterline considerably.

Happy sailing.

Peter O'D (Sanda Isle)

Peter OD
United Kingdom
50 Posts

Posted - 17/06/2011 : 00:07:04
Paul's 6 knots gives a waterline length of fractionally over 20ft which would be just about correct if Corsair were not far from upright.

P O'D

Iain C
United Kingdom
181 Posts

Posted - 17/06/2011 : 07:57:45
I would say to Bob that his log might be slightly over-reading for a beat, however that's about hull speed. Although new sails will aid pointing, and he might be able to reef later due to flatness and lack of stretch in the cloth, assuming that the cut is identical to the existing sails.

To me the biggest increase in speed to be gained is a super clean hull, Summer Girl was much, much faster when we relaunched this year, under sail and power. I really wanted to scrub off again prior to the Round the Island but I won't get a chance...unless I want to stay up all night on the Friday!

Our own speed record is 10.8 knots....however that was over the ground getting spat out of Hurst Narrows on a spring tide so does not count! But we did see 6.8 through the water a couple of weeks ago...it was a few miutes after this video was shot as we turned from a run onto a broad reach past Gilkicker on our way back into Portsmouth. We'd been on a dead run with 30kts apparent on the Tacktick, so true wind in the high 30s, no main, reefed genoa. After we turned for the approach it got really breezy and the sea was piling up a bit and we actually started to surf which is when we hit the record. Notice now empty the Solent was on a summer Sunday!

http://www.youtube.com/user/iaindchrist ... CeBTlQKCms

bob shaw
United Kingdom
7 Posts

Posted - 18/06/2011 : 23:21:14
Hi Folks the figure of 6.3 was arrived at when the GPS and the log matched so I feel sure it is a 'safe' figure but in so saying I prefer everyone else's numbers. Part of the joy of sailing is the tall tales which get taller as the evening gets longer in the bar.
Thats what makes associations/clubs so much fun.
Edited by - bob shaw on 19/06/2011 07:20:28

2E0YFO
United Kingdom
21 Posts

Posted - 23/06/2011 : 18:07:51
I don't think that I have anything other than witness' to back up my speeds, but I will in the next few days sort a gps logging device, possibly an RF bassed unit to remotely record speed/position/track etc... if I get a good speed, the data is open for all to see! will put details up later!

I agree a clean hull and good weight balance makes a big difference!


Malc.

boat:- hole in water you pour money into!

Latrigg. '89.