Mast foot position and rake question.

[Chris Perry]

Afternoon everyone,

Just a general question about mast position and rake, I have read the related topics here on the forum and Nicks setup guide and just wanted to doube check before I put the mast foot back in place ( its not easy to adjust ) so I can get a good starting position and tweak things from there.

2096 is a Rusworth composite from 2000, in case it makes a difference and the mast is a repaired selden ( its being replaced soon).

The general feel that I get is that the front of the mast should be around 700 mm from the intersection of the bow and deck ( no overhang of the deck is measured) and that rake measured from the black (white) band to the top of the transom shoud be in the region of 6000 – 6010 mm ( generally back in a breeze and forward as you want/need more power).

So what I wanted to check was the following,

do you measure the deck first and then adjust the foot to get the rake ( so the deck level number stays at say 700mm) which seem most logical

If you wanted to reduce weather helm and you have 700mm at deck and 6050 top band to transom, do you move the whole rig forward ie foot and deck the same amount? ( as this would increase the distance from the top of mast to transom so to get back to 6050 you would need more rake which moves the COE backwards again Doh!!)

I know its more complex than simple numbers, but want to at least start out in the right ball park.

Your thoughts greatly appreaciated

Chris

Not long to the glossop open, the first Ok open at glossop since the 1970s so be part of the comeback……….

[burt]

i had this problem with 1774 and my mast at deck level was very far back and the mast still upright so moved the whole thing forward and seemed to have worked but still findling with mast position :oops: :?

[okgorgeous]

I would suggest that you use the numbers given on this site as a guide to where to stick your mast initially, every boat/mast/sail combination is different, you then need to sail the boat to fine tune it to the right position for that boat, which is a little bit of trial and error unfortunately.
Cheers Neil

[davecooper]

Also, which bit of your Selden got repaired? As produced, they had quite a bit of low bend, so you could set the mast a bit more upright and still crank the boom down to the deck upwind.
Dave

[Chris Perry]

Intersting point you make Dave
When I sailed at the back end of last year, I set things up as per the numbers in my post and whilst the boat felt fine in terms of balance, getting the boom down to the deck was far tougher than I would have thought normal. hence I wanted to check things….

The mast looks to have broken around deck level, and has a new peice of carbon tube for the mast foot section and an overlapping wrap of carbon bonding the old top section and the new bit together.
this starts about 200mm above the gooseneck and extends down 200mm below the deck ring so probably stiffens up that whole section.

So that could be part of the reason why I had to apply huge amunts of mainsheet tension to get it down to the deck even with 6100mm of rake. ( north DM2 sail)

It kind of makes sense….

So maybe a touch more rake is required to stop huge amounts of leech tension when the breeze picks up??

this should hopefully only be a short term thing as I hope got my new mast delivered some time in april……

Thanks again for you input.

regards

Chris

[davecooper]

Wooo! Sounds like the bottom is going to be pretty stiff now! Yeah, they either went off at deck level or fell to bits at the joint. It was a real shame they didn’t get their product a bit better sorted before they started selling it: they were first on the scene and could have been a real asset.
Dave

[andyt15064]

Is this boat going to be ready by Saturday at Glossop?

[Chris Perry]

Hi Andy

The boat is ready for the weekend, just need to remember how to sail now……

See you on saturday

If you have a copy of Completeley OK if you can bring it along I will hand over the cash.

Thanks

Chris

[andyt15064]

I’ll bring the book. I’ve still got a couple of copies left at £20 if anyone else is interested.

Andy

[leech]

I’ve got a similar issue Burt had with his 1774 with my boat I’ve just bought – with my mast at 70cm from bow at deck level I get to about 6300mm top mast to transom !

We worked out that my mast foot is about 5-6cm too far aft

I can’t move the mast foot easily (removed the bolts but it must also be glued in place).

Its not going to be perfect but does anyone have an opinion on whats the best compromise? From pure look and feel (no experience in this class yet) we set it up with a mast rake about 6100 and 77cm front of mast to bow. The boom does not get to the deck but any more rake and it really doesn’t look right + the kicker fittings are really scraping on the deck).

Cheers
Lee
1885

[davecooper]

From memory, I don’t think Seamark Nunn’s had any adjustment at the bottom mast step, so without surgery you’re stuck with your current mast position. Make sure you put the bolts back! They are vital.
I wouldn’t worry too much. When Dave Rollins was sailing 1944 (also a Seamark Nunn) couple of years back he went pretty fast and I bet his mast position was just the same.
Dave

[mr-mac]

My 1978 Seamark Nunn has an adjustable foot.

As you probs know the seamark nunn has a rectangle bit of wood with two bolts one front and one at back. On mine front bolt is set into a recess and back one isn’t. However there are 5 front holes and 5 rear ones so it can be moved a total of about 2″ from furthest forward to furthest back. Maybe this was something one of the previous owners did to the boat but it looks fairly original.

Be a few weeks till I can get a look at mine but I can take some photos and also work out if there is some way I can find out what optimum position is for mast foot on these hulls to help other owners.

John

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