MAST ANGLE

[albion]

I was up at the marina yesterday, looked at lots of sailboat, I realise the MAC M is the only one in the marina with only a forstay. My M was the only one that the mast seems to go straight up and looks like its got a forward tilt compared to the X next to my M and as opposed to all the others that had a distict rearwards tilt. I am next to Scott Forbes (ivanawfulitch) who has the X model and , like I said has the rearstay. I asked this before , how do I get the mast on the M to have a rearward tilt.

[Catigale]

Its in the tensioning of the (side) shrouds...these are the rigging elements that determine the mast shape..the uppers tighten the mast to give it rake, the lowers have to be loose enough to let the mast bend forward in short.

[kziadie]

The upper shrouds are where all rearward tension comes from, due to the swept back angle of the spreaders. I dont think you will ever see nearly as much rake as the X... the design of the M just doesnt make it practical.

Kelly

[Frank C]

Actually, the length of the forestay dictates your mast rake.
The shrouds simply lock the forestay and mast to that predestined position.

If you're ever able alter the rake appearance by tightening shrouds,
that will be a result of bending the hull, not moving the mast!

[Moe]

The forestay length turnbuckle adjustment determines mast rake. Mast rake is also influenced by how the boat sits on its lines. That can change with different load distribution on the boat.

The upper shrouds' tension determines mast bend, more so on the X than on the M from what I read here. The backstay on an X can increase mast bend near the top.

[albion]

It looks to me as if we have a difference of opinion here.

[Moe]

beene has made the comment here his M (with his huge 389 pound 75 HP Mercury) sits level on its lines, while all the other Ms he's observed sit bow down in he water. If that's the case, I suspect the reason the OP sees his rake aft as being less than other boats in the marina (or even negative aft rake) is because it floats bow down without a crew in the cockpit.

[Lease]

If you're stuck in the marina, stick a level on the centreboard case and check your fore-aft angle. You can get it level with some load distribution and re-check the mast rake with a weight on the end of the halyard as explained in other threads on this topic.

Frank is right about the foresty determining rake. The mast will only go back as far as the forestay will allow it. It is only when you have this set, that you can start with tension. More down on the uppers will induce foward bend in the middle of the mast (so long as there is sufficient play in the lowers).

I've got mine with about 4" of (overall) rake, and 4" of bend, for a total of eight inches rearward at the top of the mast compared to the bottom of the mast. All stays are tight (can't say how much as I object to paying $150 for a piece of bent aluminium - loos guage) to a low pitch thrum.

[baldbaby2000]

If you're just talking rake then adjust the forestay. If you're looking for mast bend I'm not sure you'll get much on the M when it's just sitting. Mine is pretty straight even with a tight rig. I would guess that when under sail there is mast bend though.

Daniel

[albion]

I am trying to send some photos to show mast rake and how the water line looks so you can see if my boat looks OK. I forgot how to post pictures. I am using PHOTOBUCKET. Can you guys explain the procedure to put pictures on here for me once again.Thankyou.

[kmclemore]

I am trying to send some photos to show mast rake and how the water line looks so you can see if my boat looks OK. I forgot how to post pictures. I am using PHOTOBUCKET. Can you guys explain the procedure to put pictures on here for me once again.Thankyou.

ANSWER.

[Don T]

Hello,
I thought the M had no mast bend because of the tension and subsequent binding of the rotating mast it would cause.

[albion]

Heres a picture of my boat, it seems the plimsol line is Ok and level but the mast rake looks like its angled forward.

[Currie]

Hello,
I thought the M had no mast bend because of the tension and subsequent binding of the rotating mast it would cause.

The factory recommends 1" of bow (measured at mast's center) - not enough to stop rotation. Too much would definitely bind.

~Bob

[albion]

As you can see in the picture, the boat is not bow down.