Bimini damage caused by boom

[Gypsea Wind]

My 26M is only a year old. My family and I put quite a few days on Gypsy Wind last summer/fall. I am fair skinned and like to have the bimini up for shade. I use a topping lift when the bimini is deployed to keep about an inch of clearance between the boom and the leading bow on the bimini. Depending on wind strength and the tension on the boom sheet, the boom still rubs and contacts the bimini. I have already rubbed the sunbrella off of the port side of the leading bow and have noticed some chaffing on the dodger. Allowing any more slack in the boom sheet will make for very sloppy sail shape. I have considered shortening the bimini supports another inch, but that would not solve the chaffing on the dodger.

I have been scouring the internet for some sort of nylon (or other durable material) strip that I can place over the bimini and dodger bows (on top of the sunbrella)that can take the occasional rub and chaffing without damaging the boom. Maybe something that sews or snaps onto the bows. Certainly I am not the only one that this is happening to. Has anybody come up with something that will work in this case?

Thanks, Bryan

[yukonbob]

Our dodger is in getting leather patch put on as we speak.

[seahouse]

Take comfort - the problem is neither peculiar to you, bnix, nor to Macs.

What might be a bit peculiar (in regard to sailboats in general, I can't speak specifically for your Mac configuration; mine is a Dowsar, but maybe others can) is that you cannot strike a balance between the vang or kicker, the topping lift, the mainsheets, and the bimini/dodger height to prevent the contact, especially when the mainsail is out.

When the mainsail is not up (docking / mooring), the problem is easily solved by a shortened topping lift, so the problem should be a non-starter at that time. The vang and mainsheets still do need to provide some tension against it to prevent unwanted swinging.

However, when the mainsail is up, you are limited by the priority of the mainsail trim, which unavoidably gives you the interference and wear problem (?)

So leather (a la yukonbob), or leatherette, sewn for the first few inches around the border of the offending area, is what I've seen used for that, plus it is located where you would normally grab with your hand for security, so it also prevents dirty fingerprints from accumulating on the (white?) canvas.

Ballistic nylon is more abrasion resistant than leather by several times (at least as tested on motorcycle attire skidding down the road...European ballistic suits replaced my leathers 10+ years ago) but I have not seen it used in this application, presumably because it also provides more friction, preventing the boom from sliding across it so freely. And depending on what your basement or garage looks like*, you might find a piece of rubber hose or tubing that's the right size and colour to be slit and snapped over the bimini or dodger edge and canvas to protect it along that area .

In any case, whatever material is used, I don't think that it should be viewed as something that you want to rely on full time to prevent wear, but instead as a “band-aid solution”; something that just occasionally fends off wear.

If the bimini height measures (use a tape measure on both sides) symmetrically, then the stay tension and mast alignment might not be, giving you the uneven wear you observed. Swing the boom all the way starboard, measure the height to the deck. It should measure the same at the same points when swung to port.

You might also find that you can adjust the dodger height (a wee bit might be enough) by playing with the frame members and canvas tension. They can sometimes be adjusted by loosening straps, set screws and sliding pivoting brackets along. Hard to tell without seeing them, but the dealer might help too. Bear in mind that I'm typing in my home office and trying to remember what something that I haven't seen in several months looks like.( = disclaimer)!

I would think that the compatibility of the particular mainsail and its position on the mast (and maybe excessive rake?) versus the configuration of the bimini and dodger frames is the real issue that needs to be addressed for a long-term solution to the problem. The catch 22 at the time of their design is to make them as close as possible to the boom to maximize space, and yet not so close that they contact. Sounds like some “course” fine tuning of some details should get you there.

Good luck – Brian.

*Mine looks just fine. Yeah. We'll go with that.

[seahouse]

Actually - just came to mind - bathroom shower rod covers, an already split tube, cheap, different colours, cut it to length, often available at the hardware store, though likely not UV protected*, would snap on and might provide a few years' service as edging.
* note that black plastic, which often contains carbon black as a filler, which is UV opaque (think car tire) , might last longer than other colours in the sun when that was not its intended use.

[yukonbob]

Yes the leather is sacrificial. Hope to get 5-7 years out of it and by then I might just need a new cover or a bigger boat

[RobertB]

On the other hand, you can always adjust the boom to eliminate the interfenence

[seahouse]

On the other hand, you can always adjust the boom to eliminate the interfenence

Not without negatively affecting sail shape / sail trim, as bnix points out.

[Highlander]

If u have the Dowsar full enclosure the bimini does not interfere with the boom as seen in these old 2008-9 vids of my boat
http://s235.photobucket.com/user/maccut ... 3.mp4.html

http://s235.photobucket.com/user/maccut ... 1.mp4.html

J

[RobertB]

On the other hand, you can always adjust the boom to eliminate the interfenence

Sorry, I meant adjust the bimini - been a long week

[gabid]

On the other hand, you can always adjust the boom to eliminate the interfenence

Not without negatively affecting sail shape / sail trim, as bnix points out.

I recline the bimini aft based on the boom position. It's not perfect but usually works well when just trying to hide from sun.

[March]

Band aid solution? Duct tape. When the boom rubs through it, it can be replaced in a jiffy.
That'll work on the portion around the tube, but I wouldn't use it on top of the enclosure, or you'll lose waterproof qualities around its edge

[DaveB]

Cut off the legs of the bimini support to lower it, worked for me.
I cut it down three times and still to short.
All kidding aside, ck your mast rake, should be 1-2 degrees raked aft. More than that will cause your boom to hit your bimini.
Rake your mast aft just enough to let the boat head up to windward in a heavy gust.
You don't want a lee helm in a heavy gust as this will fall the boat off, creating more wind on the sails. lee helm is from mast being to straight. Why the Mac. has a 1-2 degree rake aft.
You also can cut 4 inches off the mainsail leech, but better to cut down bimini poles.
Ck your headroom first before you cut down the bimini poles, if you think it will be to short than you will need to cut the leech of your mainsail.
Dave

My 26M is only a year old. My family and I put quite a few days on Gypsy Wind last summer/fall. I am fair skinned and like to have the bimini up for shade. I use a topping lift when the bimini is deployed to keep about an inch of clearance between the boom and the leading bow on the bimini. Depending on wind strength and the tension on the boom sheet, the boom still rubs and contacts the bimini. I have already rubbed the sunbrella off of the port side of the leading bow and have noticed some chaffing on the dodger. Allowing any more slack in the boom sheet will make for very sloppy sail shape. I have considered shortening the bimini supports another inch, but that would not solve the chaffing on the dodger.

I have been scouring the internet for some sort of nylon (or other durable material) strip that I can place over the bimini and dodger bows (on top of the sunbrella)that can take the occasional rub and chaffing without damaging the boom. Maybe something that sews or snaps onto the bows. Certainly I am not the only one that this is happening to. Has anybody come up with something that will work in this case?

Thanks, Bryan

[Gypsea Wind]

Thanks for the input everybody.

Duct tape!?! Now why didn't I think of that! I will add that to my list of uses for duct tape - chaffing guard.

I like the idea of leather (Yukonbob) and the shower rod cover (Seahouse)I will check out on my next trip to Wallyworld.

I will check out the mast rake and see if the bimini and dodger frames can be adjusted a bit. I am also looking at a few different styles of "rub rails" that I may be able to mount directly over the rails that are affected.

The boom does not usually sit in contact with these areas. Occasionally a gust or a change in direction will move the boom across the bimini and dodger and the momentary slide across is what is causing the damage. I had a extra piece of sunbrella that I had sewn on as a patch in the damaged areas, but that will be torn up again on the next trip if I don't come up with a more durable solution.

I will let you know what I end up doing.

Thanks, Bryan

[DaveB]

My father was a Duck Tape/ Visegrip type of man. Temps are only a solution that last for a short time.
Fix the problem and lower your bimini by cutting off the tubeing were it attaches to 3-4 inches.
This will drop the Bimini about 2 inches as the rake support bracket is at a 45 degree angle.
If the lower fitting has a screw, take it out cut 4 inches off tubing than reattach.
If it has a rivet than drill the center hole to release it and put in a tru bolt.
Over time your main sail streaches, this causes your leech to become longer and the boom to go lower.(hitting the Bimini)
Make sence yet? Lower your bimini or recut your sail or order a new one with less leech.

Dave

Thanks for the input everybody.

Duct tape!?! Now why didn't I think of that! I will add that to my list of uses for duct tape - chaffing guard.

I like the idea of leather (Yukonbob) and the shower rod cover (Seahouse)I will check out on my next trip to Wallyworld.

I will check out the mast rake and see if the bimini and dodger frames can be adjusted a bit. I am also looking at a few different styles of "rub rails" that I may be able to mount directly over the rails that are affected.

The boom does not usually sit in contact with these areas. Occasionally a gust or a change in direction will move the boom across the bimini and dodger and the momentary slide across is what is causing the damage. I had a extra piece of sunbrella that I had sewn on as a patch in the damaged areas, but that will be torn up again on the next trip if I don't come up with a more durable solution.

I will let you know what I end up doing.

Thanks, Bryan

[stuendan]

As mentioned in an earlier discussion on this very subject, the Mac26M manual actually includes a diagram including measurements to check or set the mast rake. A good starting point before you get into the more serious and permanent solution of cutting Bimini struts.