A new design boom cover - am I missing something ?

[Bill O]

MikeM,
Wow very nice and a Frers design also.

Didn't know you were another Great Lakes guy. I grew up in MI, but on the other side closer to Port Huron.
If you do find any boom pics would still love to see your ideas for the "rack". Or if you could generally describe your boom build that would great.

Another rack design we saw in Grenada a couple years ago made of aluminum.

[Aaarrgh]

I'm a painting contractor (38 years), and have used this apparatus for all these years. I've been pondering how to use these (two or more sets), as opposed to installing a lazy jack rig (at a much lesser cost. They can be cut to the exact size suitable to stack the bulk size of your sail. If I act on this idea in the next couple of weeks, I'll post pics.

https://www.amazon.com/Louisville-La...SIN=B0000CBILQ

Aarrrgh!

[Dave_S]

This is what I have come up with. It should minimise windage when the sail is down.

The back end should hide the sail in the silhouette of the boom but the forward end will sit well up above and slightly below so I can't remove all the windage.

I thought about the antler rack type of platform but it will create turbulence where the tray type should improve air flow and reduce the air spilling under the sail. I don't know by how much but it can be by a surprisingly significant amount, my expectations are lower but I expect I will notice the difference.

The biggest step in performance should come from having no sail cover to shroud 4sqm of sail.

I haven't drawn up the braces, fixings, grab, strap, drain, or press stud holes until I have a final measure. I'm worried about the stack of sail cars up the mast 1.2m so I have decided to do the sail cover in two parts, the first is easy along the mast. The second one to wrap the mast I'll measure up once it is in place.


Any feed back would be appreciated.




.

[Lambretta]

Hi Dave
What you are referring to is called hay rack (here in South Africa!) and I have a good mate in the mast and boom game and that is what he calls it. I am busy with a new build of a 50ft semi custom cat and I will definitely being going with a hay rack on my boom. I would caution against doing this in solid form as it could trap rain water and this can cause mildew etc to form in your sail. Another way to do this is to look at the attached photo ..... this design is light and very strong and has the added benefit of being grab rail will working at the boom. Then between the two outer edges of the hay rack you need to fit a strong mesh for the sail to rest on (and you can walk on it if need be) these can be made with a track - for the stack pack bag and the mesh support. The mesh allows for breathability and to stops birds trying to make nests in your stack pack when you are not on the boat! The only down side I can see for this design is that the boom will hit the shrouds slightly earlier on run. If this is an issue for you then you can build the hay rack in two sections with gap for the shrouds ..... A friend did this on his mono for this reason.
Other positives to this hay rack design are it makes raising the main a lot easier as the lazy jacks are a lot wider and your stack will be lower (as you mentioned) and the management of the whole stack pack becomes easier.

[Lambretta]

Hopefully now with the photo[ATTACH][/ATTACH]

[alansmith]

Dave and Lambretta, great thinking, illustration, and design. Much appreciated.

[Franziska]

Good ideas.

One more thought.

How about building it in a way that it actually CAN collect rainwater and funnel it to the freshwater tanks.
Would need a way to drain away from the sail though...

[Dave_S]

Originally Posted by Lambretta

Hi Dave
What you are referring to is called hay rack (here in South Africa!) and I have a good mate in the mast and boom game and that is what he calls it. I am busy with a new build of a 50ft semi custom cat and I will definitely being going with a hay rack on my boom. I would caution against doing this in solid form as it could trap rain water and this can cause mildew etc to form in your sail. Another way to do this is to look at the attached photo ..... this design is light and very strong and has the added benefit of being grab rail will working at the boom. Then between the two outer edges of the hay rack you need to fit a strong mesh for the sail to rest on (and you can walk on it if need be) these can be made with a track - for the stack pack bag and the mesh support. The mesh allows for breathability and to stops birds trying to make nests in your stack pack when you are not on the boat! The only down side I can see for this design is that the boom will hit the shrouds slightly earlier on run. If this is an issue for you then you can build the hay rack in two sections with gap for the shrouds ..... A friend did this on his mono for this reason.
Other positives to this hay rack design are it makes raising the main a lot easier as the lazy jacks are a lot wider and your stack will be lower (as you mentioned) and the management of the whole stack pack becomes easier.

Good point,

I like the solid form. I'll put some thought into it. Thinking now maybe a removable, or if not possible, a permanent fast drying lining that suspends the sail above the tray to allow it to breathe.

[Lambretta]

Originally Posted by Dave_S

Good point,

I like the solid form. I'll put some thought into it. Thinking now maybe a removable, or if not possible, a permanent fast drying lining that suspends the sail above the tray to allow it to breathe.

I agree the solid form has a far better asthetic
You could fit or mould a track into the hay rack to suspend the mesh above the boom to create ventilation and/or maybe even put some small breather holes along the hay rack (at its lowest section) to allow it to drain quicker. Dont forget ot close the end of too otherwise you will have a bird nesting there in a flash

The only downsides of the solid form (IMHO) are that you lose the grab hold functionality (not a big deal) and price (which might be )

If you fit a track to the top of each side of your design you can then fit an easy to remove top section stack pack that can zip the whole thing closed and protect your sail but can easily be removed for longer passages to improve sail performance .

[Sos]

Originally Posted by Dave_S

This is what I have come up with. It should minimise windage when the sail is down.

The back end should hide the sail in the silhouette of the boom but the forward end will sit well up above and slightly below so I can't remove all the windage.

I thought about the antler rack type of platform but it will create turbulence where the tray type should improve air flow and reduce the air spilling under the sail. I don't know by how much but it can be by a surprisingly significant amount, my expectations are lower but I expect I will notice the difference.

The biggest step in performance should come from having no sail cover to shroud 4sqm of sail.

I haven't drawn up the braces, fixings, grab, strap, drain, or press stud holes until I have a final measure. I'm worried about the stack of sail cars up the mast 1.2m so I have decided to do the sail cover in two parts, the first is easy along the mast. The second one to wrap the mast I'll measure up once it is in place.


Any feed back would be appreciated.




.

This looks like a great idea. Easy to laser cut slots for drainage before folding the trays.
Would you still need lazyjacks? I would love to get rid of them and am liking this idea.
Please keep us informed of your progress

[Gulliver 2]

Originally Posted by captmikem

I will have a look, will have to scan it because it was pre digital cameras.. 1990... doesn't seem that long ago... Here is the only digital photo I have...

Wowww nice boat!!

[Dave_S]

Originally Posted by Lambretta

I agree the solid form has a far better asthetic
You could fit or mould a track into the hay rack to suspend the mesh above the boom to create ventilation and/or maybe even put some small breather holes along the hay rack (at its lowest section) to allow it to drain quicker. Dont forget ot close the end of too otherwise you will have a bird nesting there in a flash

The only downsides of the solid form (IMHO) are that you lose the grab hold functionality (not a big deal) and price (which might be )

If you fit a track to the top of each side of your design you can then fit an easy to remove top section stack pack that can zip the whole thing closed and protect your sail but can easily be removed for longer passages to improve sail performance .

I think I've decided.

I am going to change the profile of the haystack so that the folds at the outer edges of the sail are supported when collapsed holding the sail above the platform then cut drain holes and grab handles into it.

[Dave_S]

Originally Posted by Sos

This looks like a great idea. Easy to laser cut slots for drainage before folding the trays.
Would you still need lazyjacks? I would love to get rid of them and am liking this idea.
Please keep us informed of your progress

I am going to cut holes for attaching the lazy jacks because I think I will still need them but if it looks like they are unnecessary I can remove them.

It would be nice to loose them.

I'll post up my progress.

[Dave_S]

Thanks to everyone for your input, much appreciated.

[mikereed100]

Originally Posted by Dave_S

A wider lower profile boom bag. Can anyone think of a reason why not ?

My boat gets pushed around more than most in the wind at the marina and I'm up for a new boom bag. I thought I can fix two problems with one solution and save some money while I'm at it.

If I make a hard lightweight platform on top of the boom to form a wider bed for the sail to lie on when not in use I can halve or more the surface area to the wind of the bag.

Other side effects/benefits :-

• the lazy Jacks will be wider apart
• the cover can just be press studded to the bed and wrapped around the sail. Then the cover completely removed when sailing to improve air flow
• The cover can be just a 2D piece of fabric with press studs fitted - cheap
• the sail bed would be formed to act as a winglet to the main and reduce pressure losses from under the sail (no reefs only)

I can only see benefits but there must be some reason all booms aren't made this way ?

I have threatened to do something like this many times on our boat, then my wife says "what are you thinking" and we go sailing and I forget about it for another year. I like the idea of a solid, more widely placed attachments for the lazy jacks, but if you are going to all the trouble and expense mainly for decreased windage in the marina you may find the cost:benefit ratio fairly high. You can use your CAD program to calculate the windage decrease gained by lowering the profile of the main a bit. I think you will find that, after you add the windage of the hulls, cabin, mast and rigging, the percentage decrease in windage will be quite small.
On the other hand, you sound pretty jazzed about the project, so never mind me and have fun. Look forward to seeing the results.