Folding mast Mainship 350/390 1999

[Jaysr]

Buying 1999 350/390 trawler, need to remove existing radar mast, either buy or modify existing radar mast to folding mast. Home port bridge issue. I would appreciate any help. Jay

 

[tachyon]

Hi Jay, welcome to the Mainship world! I have modified my 2003 390 mast to fold, choosing to add a hinge plate assembly between the mast baseplate and the deck. There are no mods to the mast required with this arrangement. The hinge consists of two square aluminum plates, hinged at one edge, with the lower plate attached to the deck with the original screws and the upper plate drilled and tapped to match the mast. Where the two square plates extend past the round mast baseplate, there are studs threaded into the lower plate and matching holes in the upper plate. I use two knobs to clamp them together. The hardest part of the project was releasing the bond between the baseplate and the deck (a few hrs with a paint scraper finally did it). Sorry no pictures (boat is still shrink-wrapped), but I'd be happy to post some soon. The guys who do my shrink-wrap love the arrangement!

 

[tachyon]

....found some pictures

Jay, heres some photos taken during the install. Not great but you can see the concept.

 

[johnsct]

I own a 97 350 and my mast has a hinge installed about 2' up from the deck. This allows the mast to lay down on the deck within the rear railing, ie no overhang, and you don't have to detach the base from the deck. I'm not sure if it came that way from the factory or not, I suspect not. One thing I insure when the mast is folded that I have canvas covering the hinged part to insure no rain etc gets into the area and ultimately the deck.

 

[tachyon]

Hi John......I considered that approach when doing mine but thought there may be clearance issues between the mast "wings" and the railings around the stair openings. I'm not really a fan of the single-point mounting of this mast, especially after installing the radar, so we travel with a kit of lines that clip to the "wings" and tie to the railings when we're facing rough water. I read somewhere that Mainship put a 35lb limit for gear placed up there, but, to my knowledge, did not offer a hinged mast option.

 

[BandB]

Hinging masts is a common requirement on many boats, not just Mainship. There are several places in South Florida to get it done if you choose not to do it yourself. Pipewelders is who we got to do ours. They also hinge a lot of arches.

They are the builder of many arches and tops on new boats. They've built for Hatteras and Sea Ray and others.

 

[Jaysr]

Jay, heres some photos taken during the install. Not great but you can see the concept.

Thanks for help it is appreciated. Do you or anyone else know who made the oval extrusion for mast? All i can find are true sailboat mast extrusions. I am going to raise the piviot point up. If I had a small piece of the extrusion I could pre make a timplet for hinge plates.

 

[Jaysr]

I have also found a small area on the starboard walkway stern location step up which has a very small crack line in jell coat. Any ideas about best way to fill. I do not want to get moisture on wood and want to make crack disappear ? Also during purchase survey I found 6 areas about the size of a quarter bubbled out on the stern platform, aft of the actual hull. Surveyor did not seem concerned should I be?

 

[tachyon]

Jay, would it help if you had the dimensions of the mast cross-section? I'm not sure how far away from your boat you are, but I'll be at mine on Monday and could measure it for you. I'm assuming you'll mount the hinge plates orthogonal to the mast axis?
I have no idea where Mainship got that tubing.

 

[Jaysr]

Jay, would it help if you had the dimensions of the mast cross-section? I'm not sure how far away from your boat you are, but I'll be at mine on Monday and could measure it for you. I'm assuming you'll mount the hinge plates orthogonal to the mast axis?
I have no idea where Mainship got that tubing.

Yes, that's the plan, hinge aft. I have measured but actually having a profile would simplify. I plan on making the 2 plates to fit mast profile, install gasket, hinge pin,. forward lock bolts, then cut mast. Having an actual piece to template plates would really help.Thanks Nick your reply was truly appreciated JAY My profile is appx 3" x 6" oval

 

[WMinder]

Hello Jay. Purchased a 2001 390 and am planning to do the loop and the Erie Canal so have a need to hinge the mask. Can you share with me how your mast project came out? Did you end up hinging up from the deck or did you hinge at the deck? Have your been happy with the result? Has water intrusion been any issue? Appreciate any help/feedback you could provide. Thanks. Bill Minder

 

[captkev]

I added a hinge on my '99 MS350. I also added 12" height to the mast getting a clear view forward over the bimini. When folded the radar drops inside the stern rail and rest on a piece of PVC pipe. I designed the hinge and can probably find the drawings if you are interested. I will look for pictures of the project, have them somewhere. The bolts are 1/2in, the aft is "snug" with nylon lock nut, forward is finger tight for easy removal.

 

[WMinder]

Thank You for the reply. If you come across your drawings would certainly appreciate you forwarding as I little to no engineering skills. If you text me I will forward my email. Bill MInder. 239-571-9646

 

[jclays]

I have a 1997/350 The mast is hinged a little above the mid way point. The mast was cut and a heavy hinge was welded to the two pieces with removable pin that keeps the hinge locked when the mast is in the upright position.

 

[BBS]

Tachyon,


I'm very interested in the hinging method you used on your 390. Do you have any drawings/dimensions/measurements for the hinge plates that the mast base attaches to, including the o-ring groove that you could share?


Brian

 

[Lshulan]

Is there enough slack in the wires that permit the hinged bend? Are the wires loose or in a tube or similar?

 

[Lshulan]

How thick are the aluminum plates? Were the hinge parts custom made or welded in? In a separate question I asked if there’s enough slack in the wires?