Sunday, November 21, 2010
Update form a sail at lane cove,
The boat performed fairly well on the weekend, with the hull keeping up with the faster boats upwind and showed good downwind speed if not equal with the faster cherubs. Breeze was around 10 knots with gusts of 15. The sails were from my old boat and did not fit particularly well. Especially the spinnaker due to the further aft mast position and rake, So i needed to place strops on the tack and head to get some sort of "slack" in the luff, which produced a difficult to handle spinnaker.
With this in mind the rig has basically be placed in the boat using generic values of rake and an unknown rig tension, so I'm hoping that with some tuning and re-cutting/ new sails it will prove to be a very fast boat in medium to heavy airs.
Preliminary cost of the project is as follows:
Jig materials - $550
Hull materials - $3950 (Resin, carbon, foam, consumables etc)
Power tools/ consumables - $400
Fit out - $3550 (CST rig, stays, fittings etc)
Total Cost - $8500
Although this cost is likely to be around $9000 after a few more ropes/fittings, also sails need to be considered.
I will give a more detailed cost breakdown further down the track.
Monday, November 15, 2010
Well she has finally managed to get out onto the water. With a large amount of work being put in over the last couple of days she finally got a sail in.
The helm felt good but i will pay more attention to it on the next sail and try to work out if the rudder balance of mast rake/centre board position needs changing.
The boat responded well upwind when there was a decent gust, but did bog down a fair bit in the lulls. Though i think with a bit of careful fore aft trimming we will be able to solve this. The hull seems to move quit nicely through the chop while down wind it didn't seem to have some massive urge to nose dive, although we were only hiking (maybe 15-20knot gust) but it did feel quick.
The cockpit layout and rig position so forces the crew to sit further aft in the boat during tacking/gybing etc, which could lead to a problem of the transom sinking a little during tacks etc, which would mean it will be slow out of tacks.
In conclusion I'm very pleased with how the boat turned out and now my crew and I will need to focus pretty heavily on the fore-aft trim and setting up the rig position/rake to make to boat work well.
I'll let you know how she goes against some other boats hopefully next week.
Saturday, November 6, 2010
Started to fit out the boat over the last couple of days with the help of the old man. Once our fittings arrived from ronstan we double check the dimensions of each fitting and its location and made a bolts list for each fitting. This resulted in several different lengths of M4 or M5 (metric) bolts being used over the whole boat in order to 1. keep weight to a minimum, 2. prevent bolts protruding into the spinnakers chute/bow pole area etc.
The bolts used were 304 grade stainless as our local store did not supply 316 grade, without ordering them in boxes of 100. So this just means that good care of the boat is needed to ensure that salt water is washed off when ever possible to minimise corrosion... on the plus side 304 is stronger than 316 grade and slightly cheaper. All up our bolt order for the bolt cost approx $100, which included several shackles and a 50 x 6mm tow ring.
All fittings on the floor and side tanks are attached to be boat by taping threads into pre-located fibreglass or carbon fibre "blocks" laminated into the floor.
The mast step is made from 2mm thick 6061-T6 aluminium, which i tig welded in the workshop at uni. The side stay and lowers mounting bracket is made from 2mm 304 stainless steel, which i also made in the workshop.
The overall rig length is 6.49m with a goose neck height of 640mm above the sheer (1000mm off the floor). I will upload a "plan/drawing" of the finalised rig once it is completed.
We roughly placed the rig into the boat this afternoon to try and estimate the stay lengths required. To do this we set the rake on the mast so that the tip was vertically above the back of the centreboard case (or equivalent distance in our case) as is a generally rule of thumb for cherub rigging. From here lengths were taken as were additional measurements of all rig fitting locations so that i can create a spreadsheet to calculation stay lengths and the effects of rake change/mast step position on length etc.
After the initial rigging today it looks like I'm going to have some "fun" trying the make the sail plan work for the boat. The jib requires a very long foot due to the mast position (6ft from the bow, as opposed to 5'6-8" or so for normal boats). I anticipated this and placed a large forestay mount on the boat allowing it to come back about 120mm, so I'll let you know what i can come up with.