[C320-list] Dodger and Bimini Rub

[Scott Thompson]

None of the choices are very good.

1.  Raising the lower blocks can't change the angle much unless you 
raise the blocks a lot, and the shackles that you use to raise the block 
would have to be very strong.  You also risk having a lot of metal 
banging around during jibes.

2.  Rebuilding the dodger is expensive but does not involve any 
re-engineering of the highly loaded boom system.  You might end up with 
not enough room to swing a winch handle on the halyard winches, which is 
the situation on my boat.  And to the extent that you change the angle 
to the aft block it will be by reducing the turn angle at that block, 
which will in turn require more mainsheet load for a given amount of 
downward force on the boom.

3.  Moving the aft block on the boom has potential negative effects on 
structural integrity:  It reduces mechanical advantage a little 
requiring slightly more mainsheet tension.  More importantly, it 
involves having additional holes in a very highly loaded part of the 
boom, possibly leading to stress fractures and failure.  And by moving 
the boom blocks closer together it will further concentrate the stress 
on the boom, which already is pretty concentrated given our mid-boom 
sheeting arrangement.  I would consult a rigger before doing this.  I 
assume you will want stainless rivets, and will need to take proper 
precautions against galvanic corrosion where these are mounted in the 
aluminum boom.

4.  A new traveller in the same location can't change things much.  I 
wouldn't go down this route unless you are certain that the traveller 
will be enough further forward of the existing one to solve the problem.

5.  Are you absolutely certain that the problem is not due to the way 
you are sailing the boat?  You might want to post a picture showing the 
setup of mainsheet and traveller in a situation where you are having the 
problem.  Have you considered adjusting the traveller / mainsheet / vang 
combination in order to see if you can make the problem go away?  You 
might move the traveller a bit more to weather or a bit less to weather 
and/or adjust mainsheet and vang tension, for example, to change the 
angle of the sheet as it rises to the boom.  If the sheet is essentially 
straight up and down when the problem occurs I would try easing the 
sheet and moving the traveller further to weather, for example.

There are a lot of 320's on the Chesapeake.  I suggest you take careful 
measurements of your boat and then find other owners to compare notes. 
Make sure it's the boat and not the way you are sailing it before you 
change anything.  Apologies in advance if you've done this already.

Scott


Stephen Cox wrote:
> There is a fourth option, install the new Garhauer Traveller that comes with
> the MK II.  I have a MK II with factory dodger and there is no rubbing of
> the main sheet blocks.
> 
> Stephen Cox
> Tegwen #1141
> 
>> -----Original Message-----
>>
>> Hey Everyone,
>>
>> I have queried the group in the past about the factory canvas 
>> on the later model 320s (2000s w / factory canvas).  To 
>> refresh, the main sheet is angled such that is rubs the top 
>> front of the dodger.  The boom also rubs the top of the 
>> bimini however that is less of the problem.  
>>
>> I had proposed two solutions, and now have three.
>>
>>   1.. Move the main sheet blocks up higher (off the traveler) 
>> to cut down the angle.
>>   2.. Have the dodger lowered (front tube only) and have the 
>> canvas re-cut.
>>   3.. Move the bale forward on the boom. (1 inch would 
>> probably do it...) I went to visit APS (Annapolis Performance 
>> Sailing) and they highly recommended against 1 and suggested 3.
>>
>> Has anyone moved their bale forward on their 320 and if so:
>>
>>   a.. Was it difficult to do if they did it themselves? 
>> (involves drilling rivets, drilling new holes and re-riveting.)
>>   b.. Is there any engineering concerns?
>> I know that some Hunters are rigged the same way and have the 
>> bale even more forward than the Cat 320.
>>
>> Any thoughts on this?  Thanks in advance!
>>
>> -Brad, Mary, Monica, and Jarod
>> "Independence"
>> 2004 Catalina 320 Hull 1006
>> Middle River, MD   
> 

-- 
Scott Thompson
Surprise, #653