Hi, I've refurbished a UK Class 5 landyacht K101. And recently sailed the yacht in the first bit of strong wind I've been able to get out in. 25mph. I had set up the axles and camber with the method I posted up on this site a couple of months ago. The first run in the morning was all good. The wind was on shore, so the course was a simple reach to the gybe turning mark and then the bottom mark was a tack. No problems.

Here's where it gets interesting. I re-tracked the yacht on a fellow club members specifically made tracking device on his road trailer. We also changed the camber. More upright than before. The yacht was also set up with just a little toe out, less than I had been running.

We raced the same course. The yacht was instantly more scitish, faster but was noticeably more difficult to get around the gybe mark. The up wind mark was a different matter. On turning into the up wind the front wheel lost traction instantly, with total loss of control. I tried various methods to improve the tacking of the yacht. Changing line into the corner, sitting up to shift my weight forward etc. But to no avail, I kept loosing front wheel traction and control. Ending up with the yacht fliping backwards.

I was keeping the sail sheeted in as much as I could, but I have to easy it slightly from just above my eye line to skim the top of my helmet.

Is this issue purely down to not sheeting in enough? The sail was luffing a bit going into the turn, due to possibly extra apparent wind due the extra speed relative to the mornings session. Or is something else going on?

We talked about it at the club and there was some suggestion that extra weight, in the form of some lead is sometimes applied over the front wheel and ballast is also out in the body of the yacht. Also suggested was a slightly longer mast to allow me to keep sheeted completely through the tack.

I'm 5'3' and 10 stone, so the foot controls are as far forward as I can get them and I guess my upper bodies mass is slightly further forward than most?

Any ideas, suggestions? One last thing the wind may have got up a little bit more in the afternoon, topping out at 29mph

Thanxs for the reply aus230.

I'm running push rod steering and Maxxis hookworm tyres.

Here is a video of the morning session:

Unfortunately my camera ran out of card space before the afternoon, as it would have been interesting to see my boom angle.

I will have a play with mast rake.

Does anyone know how to calculate the center of lateral resistance on a land yacht? I can do the sails center of effort but I'm struggling with trying to work out a way of working it out for the yacht.

Hi I changed from a hookworm to a miracle the difference was quite notable I think Hiko found the same.
Cheers
aus230

landyacht said...

as soon as you toed it out you made the frontwheel fight the rear wheels to change direction
just put it back, even try setting it parallel
also consider that your sail may be a bit full in that kind of wind so maybe a set of stiffer battens to flatten the sail so you have less low end grunt when coming into your turn, particularly in the head of the sail. definitely dont let the sail flap at all upwind

OK will try that. That's what I thought originally. Them that know over here in the UK say that 1/4" toe out is what to run. I wasn't sure about it but...

Yes my outhaul channel needs lengthening, I noticed that one too! You can see me trying to pull it in the video!

I think the previous owner took a little bit off the mast tip for some reason, I'm going to add it back so I can sheet in more and still have the boom out of my face. With being short I'm further into the cock pit so my face is where the boom end is.

Had a very quick look at the thread linked, I had seen it before but thought it mostly dealt with CofE of the sail. I know that bit. Quickly looking at the end of the tread it looks like that is the conversation I need... CLR of the yacht.

Thanks... sorry if going over old ground.

Ok this is what I get. There is a little distortion of angles due to where I took the pic from but... It looks to me like I need to shift the balance point forward with some weight over the front wheel. Or increase the mast rake quite a bit. Or both.





On a slightly different point. Class 5 rules say 5.50m from mast tip to ground. Does this include the tang to tie off the sail on? Can't see any reference to this on FISLY.

Sure thing, good advice.

Any feelings on shifting the balance point to aline / balance with the balance point of the yacht with the things I suggested?

On the mast height, I mentioned it as one suggestion was to add a little mast length to enable me to keep the boom above eye line and max sheet tension through the tack. There by stopping the sail from luffing and upsetting the balance as I turn into wind to tack. And having measured it I don't have a lot of room to play with, so I may have to alter the sails foot if I have to include the tang.

Difficult to remember if the yacht had a bias toward heading up or bearing off. I don't think it did. But the beach was quite ribbed and so it was pretty shakey ride, and I had to keep my feet on the pedals for control. What I do know is that turning into the Gybe mark was fine, all be it quite a wide turn. And turning into the upwind mark was none existent. No front wheel grip and back flips.

Was the yacht designed for 19 inch wheels and now has 26 inch wheels?
Might explain the excess height of mast and lowness of boom
What is the ground clearance of the seat? perhaps a clue here
What is the weight on the front wheel fully rigged, sheeted in and pilot aboard ?
Class 5s tend to be light in the front and if you cant sheet in hard on upwind
tacks turning can be a problem and can flip you back
Maxxis miracle tyre on the front helped my yacht turn much better but more weight forward would also help IMHO
Some thing to try is temporarily put some weight on the front spar tube say a couple of kilos right forward and try it out If this helps then maybe you could move the seat forward as has been suggested
You could gain a little boom height maybe by redesigning the tang at the mast head
so that it angles upward toward the sail
My understanding is the tang is part of the mast height

I know this might not be of any relevance but my old style Class5 "Wildfire" the weight on the front wheel was a firm to strong 2 finger lift with someone in the yacht lifted at the steering head stem.


Just weighed some full milk cartons in a shopping bag, about 4x 1L seems about right from what I recall so it would have be been 4-5kg on my uncalibrated "finger scales"
Just had a look at the FISLY Promo5 specs the minimum there is 11kg

FISLY class5 mast rules M5. The length of the mast shall be such that the distance from the top of the mast to its foot plus the distance from the mast foot to the ground shall not exceed 5.50 M.
pretty straight forward
otherwise the boys are right dont sheet out , dont let it flap.
I believe the quote from CARS is if ya wanna go right boy your gonna have to steer left!
try thowing the back into a slide with the sheeting in hard and held , this gets the sail aerobraking and tacks the sail even if the yacht doesnt want to.
you may break it , but were not playing a computer game here,and you get the odd bruise .
heres a thought, try a seatbelt . then you dont have to concern yourself with staying in the yacht, and can concentrate on the turning

That "tang" we call a "mast crane". Any part of it that extends higher than the actual mast would be included in the mast measurement. Also if the crane was tilted up more than 90 degrees to the mast the total length of it would be added to the mast measurement.

Depending where you are in the country get yourself over to either the Anglia Regatta -Oct 22nd & 23rd or try for the Brean Regatta - Nov 12th & 13th. Either one will have plenty of Class 5s and the pilots would no doubt help you out no end with ideas for set up.

Cheers Col

Bouncing front wheels in the turns seems to be part of having a class5
On the beaches where we sail anyway
I tried suspension on the front forks but the best improvement was the maxxis miracle tyre on the front They are grippy little devils, still bounce but are effective
when they are down Have gone back to rigid forks now
Having the seat designed so that it can be moved forward and back to change the weight distribution would be a good thing to have I think
I dont seem to get out enough in the class 5 to be able to fine tune it
I dont know anyone here who has toe in or out we set them parallel
Thanks for the feed back we all learn from it

A couple of things that I have done to correct that problem ( It now steers around corners ,does not head across country like it did sometimes)

Changed from cable to rod steering

Changed to a maxxis miracle Tyre

Adjusted the mast rake to match the center of effort

Made my steering adjustable so that I could balance my body weight to match the center of effort and move it forward to put more weight on the front wheel in strong winds

I have found that my rear wheels preform best when the are set parallel

Recorded everything each time I made a change so that I know the effect good or bad.
Still got a lot to learn though

Cheers
Vic

Nothing wrong with cable steering, I think its a personal preference, Mine worked fine the main reason I went to rod steering to make it was easy to adjust my my steering position forward and back (this was when I was when I was trying to find the best balance point in the yacht)
Cheers

Thanks for comments.

I was Marshalling a Brean Regatta and saw the Pflume that won and chatted to some Class 5 sailors.

Some weighing was done of the 5's. The method was bathroom scales under each wheel with the others leveled to the same height as the scales with the sail sheeted in to max. The front wheel weight was around 15kg.

I haven't weighed mine yet, so I will feed back when I do.

But in response;

I have a Maxxis on the front. And Hookworms on the back. I'm starting to think the Hookworms may have to much grip, hindering the turning? I'm thinking of trying some slicks I have.

I can't move any further forward, my crutch is right up against the main sheet block. I could possibly move the take off point forward.

Sitting up to move my weight forward when tacking stops me from sheeting in down to max. And makes the problem worse as the sail luffs like crazy.

C of E > C of Balance, is pretty spot on but I will try some more mast rake.

Tracking is set parallel.

And I have rod steering.