I just got a used 505. I think it is from the early 70's (sail number 3452). The rigging of the boat is basic, but
works nicely (main/jib
cunningham, boom vang, traveler, main outhaul, adjustable jib leads
(fore and aft) and adjustable forestas/shrouds (turnbuckles)).
The hull is still relatively stiff and the sails
are in pretty good conditions (I also have the original sails, but won't
use them as these one are worn out). I went towards the 505 class as we
are getting a bit heavy for the 420 class which are used in
university/college competitions across Canada. I understand that this
boat will never be very competitive, but I'd like to get as much as I
can without investing too much. My objective is to become familiar with the 505 by racing it locally.
trying to set up the boat to standard tuning sheet numbers, I realize
the mast gate is short and I cannot put the mast at the most
aft position as suggested in most tuning sheets. I understand that it
is critical to have the mast supported laterally at the gate/partner.
However, the boat is a classic and it is probably not worth
modifying the mast gate (it would require structural work). I was
thinking I could simply move the mast forward in the step and start from
there, but I'm not completely sure of the consequences of doing so.
As I don't know of any other 505 in my area (Montreal,
Canada), it's hard for me to get inputs from locals. This is why I seek for advices here.
analysed the problem with the little experience I have. Here are
different solutions I am considering right now (other solutions are the
1) Moving the mast forward in the step without
changing the recommended rake/tension settings. I think this will mainly
change the mast prebend and I will get more jib luff sag, which may not
be convenient in very low wind speed. I'm not sure if pulling harder on
the jib cunningham can fully compensate for this (any hints
someone?!?). The reduced mast prebend may also slightly reduce the
ability to depower the boat in high winds because of the fuller main
shape and increased jib luff sag. I'm not sure if I will see much
difference because I don't go out when there is no wind and also, we can
rake back a bit more or use more cunningham/outhole if possible to
compensate the effects in high winds.
2) Maintain a fair amount
of prebend while moving the mast forward in the step. To do so, I would
have to increase significantly the shrouds and forestay tension (I hope
she won't collapse). Doing so, I will probably loose quite a bit of
power as I will have a flatter main and less jib luff sag. On the other
hand, it might increase the pointing ability, but I'm not sure if it is
3) Another solution would be to move all the rig
forward trying to keep the prebend with relatively low forestay tension.
However, moving the mast away from the chainplate would probably reduce
the effect of the spreaders on the mast. Thus, I will probably fail
prebending the mast with relatively low forestay tension. I think I
would also loose some of the lateral/athwartship mast support from the
spreaders which is probably not desirable (unless I modify the spreader
My comprehension of the problem is not perfect, so I invite you to
correct me or clarify certain point that I might have missed. Any hint
would be the most welcome. Also, there are a few things that you may want to clarify:
- How does the mast position affect the slot between the main and jib and how does this affect the boat ?
What is the impact of the forestay angle (changed through mast
position) on the
shape of the jib (similar to the fact that the forestay is attached in
different location depending if it is a bag or a launcher boat) ??? Is
it sufficient to play the jib car position to compensate for that ?
understand that in all cases, I will have to experiment with the boat
and fine tune the centerboard position at the same time to adjust the
helm. I'm looking for a good starting point here. A few facts you may
want to consider while giving me some hints: winds are relatively
turbulent in my area as the lakes and rivers are relatively small, so the urban
shores have huge effects. The crew weight is on the light side (330-360 pounds) and we almost never sail in winds above 18
Thank in advance !