Hard Bimini Construction

[LarryandSusanMacDonald]

My wife and I own a 1977 Morgan Out Island. We have extensively upgraded almost everything on the boat. My wife has constructed over the years three biminis complete with enclosures - she is a very accomplished canvas worker - a professional. The current bimini has been with us for five years and is starting to show its age - it's also leaking on us - an unforgivable sin for a bimini. We've gone through all the re-waterproofing and etc. and Suzi (my wife - famed in song as Saltwater Suzi) has declared it's time for her to construct a new one.

Here's the rub: With a Morgan Out Island Ketch - the mainsail is located almost entirely over the bimini. When it comes time for dropping the mainsail folding it and covering becomes a real chore - can't reach the %$#@%^$#@ thing!

So - we are considering the construction of a hard bimini. Something I can crawl on or stand on (no mean task considering my advancing years). I have the means and the talent - but would like anyone who has had experience, knowledgeable opinions, etc. to offer advice:

1. Will my existing stainless steel 1" frame support the weight? It does not use straps to tie it to the deck - I replaced them long ago with stainless.

2. What materials would be best? I've considered wood (species to be determined; probably teak - I can get it wholesale) coated with fiberglass (either laid or sheet goods) on top and varnished beneath.

3. Would also like a window to see the sail from the helm - plexi or lexan - any preferences?

4. Would like to be able to drain the rain (after sufficient time for cleaning of bird poop) into the water tanks. Any suggestions on methods would be appreciated.

5. Any other caveats or thoughts on the matter would be appreciated.

I expect to start on the project in a month or two and will keep everyone entertained (or amused) with my progress via pix and descriptions if any one is interested.

Thanks much in advance for your input, advice and jocularity.

Cap'n Larry

[Faster]

This recent thread by SimonV http://www.sailnet.com/forums/showthread.php?t=40684

has some pictures of a nicely done hard dodger top, in fiberglass which I think makes more sense that teak (though you could probably cold mold something in more appropriate wood).

Different scale than a bimini so you may need more reinforcement to actually walk on it... but some ideas there for you.

[Cruisingdad]

Just a comment or two, so please excuse me if I get a tad offtopic on this, but where do you sail? Would you have concerns about being able to get that down in prep for a hurricane? That would also be quite heavy.

I am not trying to dissuade you from it. These are simply the reasons I have not done something similar. That is why I am asking.

- CD

[sailingdog]

Originally Posted by LarryandSusanMacDonald

1. Will my existing stainless steel 1" frame support the weight? It does not use straps to tie it to the deck - I replaced them long ago with stainless.

It depends on the design of the frame really, and what you make the hard bimini out of. If you make it out of a cored laminate, it should probably be able to take the weight... however, it probably wouldn't take the weight of the bimini well enough for you to stand or climb over it—but much depends on the actual design of the frame.

2. What materials would be best? I've considered wood (species to be determined; probably teak - I can get it wholesale) coated with fiberglass (either laid or sheet goods) on top and varnished beneath.

I wouldn't make it out of teak. Teak is rather dark and the bimini will heat up quite a bit. Most of the better hard biminis I've seen were made of a cored laminate of some sort, usually with a foam, marine plywood or balsa core.

3. Would also like a window to see the sail from the helm - plexi or lexan - any preferences?

The window should probably be made of plexiglass, since it needs to be UV-resistant, and doesn't really need to take that much in the way of physical strength. If you're planning on standing on the bimini, then you might want to go with Lexan instead... but Plexiglas has better UV and scratch resistance overall.

4. Would like to be able to drain the rain (after sufficient time for cleaning of bird poop) into the water tanks. Any suggestions on methods would be appreciated.

Should be pretty easy to do, especially if you put a slightly raised edge and gutter around the edges of the bimini, and have a fitting or drain for a hose at the lowest point on it.

5. Any other caveats or thoughts on the matter would be appreciated.

You probably want to keep the bimini's top surface white or a very light color, and paint/gelcoat the underside a bit darker a color to help reduce glare and heat underneath the bimini. I'd also attach aluminum rails for a bolt rope along the edges, so that you can add front, side and rear curtains to the bimini and use it as part of a cockpit enclosure system.

If you do put a window in the bimini, make sure you have some way of covering or closing the window... since there are times when you'll want to have it as dark as possible under the bimini... like sitting in a windless anchorage when it is 95˚ with 99% humidity.

[artbyjody]

Originally Posted by LarryandSusanMacDonald

1. Will my existing stainless steel 1" frame support the weight? It does not use straps to tie it to the deck - I replaced them long ago with stainless.

You will most likely need to add more frame members if intending to stand on it. Most Bimini designs are just design to support some water and the weight of the canvas...The issue will be the motion on top from the weight so making sure you can distribute that weight is important...But since you will be building it off-site you can test while building - I would up the size to 1.5" diameter if possible though which may allow you to use the current number of frames...

2. What materials would be best? I've considered wood (species to be determined; probably teak - I can get it wholesale) coated with fiberglass (either laid or sheet goods) on top and varnished beneath.

Do not even consider using teak and wrapping it with fiberglass....Teak has a significant amount of oils and you will never get a proper bond.....use the other suggestion instead...less 3-6 months in the heat you will be disappointed with the outcome...

4. Would like to be able to drain the rain (after sufficient time for cleaning of bird poop) into the water tanks. Any suggestions on methods would be appreciated.

In your design - drop the collection hole by 2 inches and have the tip of the pie extend 1" above - this will help in trapping solids (heavier) and the water that comes above should be fairly debri free (but have a strainer on it....Also below the top of the bimini incorporate a bypass valve in the cockpit so that you can optionally kick the water elsewhere instead of into the tank ...

5. Any other caveats or thoughts on the matter would be appreciated.

Some resources design ideas:

http://www.cruisersforum.com/forums/...ial-12774.html

http://www.tartarooga.com/

http://csysailboats.blogspot.com/200...d-dodgers.html

http://www.davestrimmers.com/photos/yacht.htm

Have fun with your project....

[SimonV]

This is a better photo of my dodger not of me. As you can see its a doger not a bimini and is therfore alot smaller. It is solid GRP 1/4" thick with
2off 2"x1" stringers over the span and it needs the centre supports to take any weight, and would intrude into the cockpit space is a bimini.

[LarryandSusanMacDonald]

Thank you everyone for your input - a lot of good ideas to incorporate into my design. You folks are obviously very experienced and knowledgeable - I'll continue reading other replies and work on the design - there were several things I hadn't considered - one important one was the shake - I thought the frame could hold my weight but hadn't thought about the wobble factor.

To answer Sailingdad - we sail the Chesapeake, the ICW and the Bahamas - so far. We don't do too much offshore work - the occasional overnighter - but never to the point which takes us outside our weather window. In the eleven years we've owned the boat - we only took the bimini down once - that was when Isabel hit the Maryland area. We were quite a ways up the West River south of Annapolis and only experienced a top gust of 52 knots. We've seen more than that (~60) several times with the bimini up and it's held quite well - Suzi makes a good bimini!

When I get a design down on paper I'll post it for a critique. I really do appreciate this forum. It's a great resource - I wish I had known about it for some of my other projects - maybe I would have done better.

BTW - there are pix of our boat on our website - but I'm not sure I'm allowed to post the URL because it's a business - we do Captained charters with our boat. Obviously I wouldn't be trying to sell to the members of this forum - but still I'm not sure. Let me know if this is a no-no - or a go-go.

Thanks,
Larry

[brak]

BTW I am planning to install a hardtop bimini/roof/whatever it is on my boat. Many of her sisterships have hard top originally from the factory, though mine does not.
I've seen 3 or 4 of them configured that way and hard top was extremely sturdy - it held boom gallows, and was strong enough to stand on. It was basically a fiberglass surface held by 6 vertical tubes (I think they used aluminum, but I probably would have to go with stainless). These boats have been in everything in 30+ years they are out there and those hard tops look pretty good still, so I guess hurricane force winds aren't necessarily a problem if the construction is done properly.

[sailingdog]

Solid GRP 1/4" thick isn't very strong all things considered. Adding a 3/8" core or 1/2" core and having 1/4" GRP total over the core would probably be strong enough that you could stand on it and wouldn't need stiffener braces or supports for it.

LarryandSusanMcDonald--

Not sure who sailingdad is, but it would probably help if you said what kind of boat the bimini would be setup on. Yes, you say it is a Morgan OutIsland, but didn't they make several sizes of that boat??? I know of the 28, 33, 41 among others...

Originally Posted by SimonV

This is a better photo of my dodger not of me. As you can see its a doger not a bimini and is therfore alot smaller. It is solid GRP 1/4" thick with
2off 2"x1" stringers over the span and it needs the centre supports to take any weight, and would intrude into the cockpit space is a bimini.

[LarryandSusanMacDonald]

Not sure who sailingdad is, but it would probably help if you said what kind of boat the bimini would be setup on. Yes, you say it is a Morgan OutIsland, but didn't they make several sizes of that boat??? I know of the 28, 33, 41 among others...

Sorry, You're right - I forgot to mention - it's a 41. It's a ketch - I don't think the 28 or 33 came with a ketch rig.