by Big_Dog » Tue May 01, 2012 7:40 am
Chris,
Congratulation. I see that you have a SB18 to play with in the Houston area. PHRFGB gave Lady C an initial rating was 245, but it has been revised down to 150. No pressure, but you could be the first i550 to race an SB18 design.
As for the mast: I’m planning to position the jib and forestay per the i550 rig dimension. That puts the mast head about 1 1/4“ higher than the i550 sail plan. I talked with a North Sail expert that recommended keel stepping the mast. I will need to cut off 6” – 10” from the bottom end. This also requires cutting out the compression post and building the step at berth height. I see a sawzall day coming.
I also talked to the local West Marine associate, which owned and raced an early Viper. He said that to get pre bend the rig loads are high than other boats he raced. Kevin is correct about the inner sleeve (Butt to spreaders). You could remove it and the Selden 3525 mast is 10% lighter than the Dwyer DM-4. Also you keep the tapered top section. If needed, I’ll could pull the sleeve later, or save for a CF. Also by cutting from the bottom end you are removing more of the heavier sleeved section. I’m thinking that I need to run wires from the mast step to the chain plates to help distribute the extra load. The spinnaker does exit needs to move up 30” (inside or out) and add stays (diamond?) to support the tip.
The Viper mast meets my requirement for a cheap first mast to get off the dock. About half the price of aluminum stick and 10-15% of CF rig. The tradeoff is the weight. 26 feet of mast is 3 lbs less than a DM-4 before adding 8 – 9 lbs of sleeve. Net is 5-6 lbs more. All boats in the SE are using Aluminum rigs.
Jon
Jon
#36 – Still In the Dawg House
Columbia, SC - Lake Murray