R21 -EC, Collapsible Mast - Support

[Stevan47]

Dear whomever: I have recentlyy bought an ex-demonstrator R21-ECfrom the local Ranger Tugs rep here in Western Australia. Great vessel - no real big issues. Still getting used to her and looking forward to many years of seagoing pleasure.

When collapsing the mast for towing/storage, I noticed that the fitted stainless steel support staunchion (f'rd of the wheelhouse, port side) which is attached to the collapsed mast with retractable pin arrangement, is not installed for optimum, efficient leverage, resulting in uneven/inefficient support of the mast. The staunchion is too far aft (close to the wheelhouse/behind the cabin hatch) and not central or directly under the actual mast. The bulk of mast weight therefore remains 'frd of the staunchion and results in excessive force being exerted, via leverage, on the mast mounting plate, then transferred to the fibreglass canopy on top of the wheelhouse. This can, and does, cause fracturing of the fibreglass, ergo expensive repairs.

I have manfactured a 'jury rig' central mast support staunchion, from marine ply, which is installed prior to towing with the mast collapsed. This takes the bulk of the strain from the wheelhouse canopy and shares the load with the existing stainless support staunchion.

I wonder has anyone thought of manufacturing a similar stainless staunchion, with a large distributing 'footprint' plate, to be installed with bolts and nuts to the focsle deck, just 'aft of the deck cleat and anchor point? This would centrally support the the mast in its collapsed state without stressing the wheelhouse canopy. Your thoughts, please?

 

[SGIDAVE]

Hello Stevan47,

I would like to see pics of your new support arrangement. I, too, have observed the support strut seems too close to the base of the mast to provide optimum support to the whole affair. But then, it is welded stainless steel and, it seems very strong regardless of the point of support. I think the strut is mainly to stabilize the mast in the forward-tilted position and rather than protect it's length from bending stresses. I trailer my boat with every use and have found that snugging up the support cables (in combination with the strut) really makes the forward-folded position VERY stable.

Good to hear from you in the Southern Hemisphere and WELCOME to the forum!

Best to you,

/david

 

[Stevan47]

Hi Dave: thanks for the response. Please see my photos which I will send via separate email. Would appreciate your advice. I see your point about the support infrastructure, but what I was actually concerned about was the length of overhang, f'rd of the vertical staunchion, which then places undue stress on the fibreglass roof canopy section, resulting in stress fractures around the screw holes. See where I am coming from? See what you think anyway - let me know wha you think. Kind regards, Stevan.

 

[Dave and Genny]

We would like to see the pics too! gensterenberg@gmail.com

 

[jzois]

Greetings, might as we'll send photos to me as we'll. I'm mounting a radar soon so alternative support may be wise. Jzois@amctheatres.com

Thank you,

John

 

[SGIDAVE]

Greetings, might as we'll send photos to me as we'll. I'm mounting a radar soon so alternative support may be wise. Jzois@amctheatres.com

Thank you,

John

We would like to see the pics too! gensterenberg@gmail.com

With Steve's permission I am posting his pics here:

Again, to clarify, these are pics of Steve's mast support prototype.

/david

 

[Dave and Genny]

Thanks for the pics. Our 2006 21-EC mast collapses to the side. Anyone have ideas for supporting it during transport? We do day trips and always remove it for trailering.

 

[SGIDAVE]

Thanks for the pics. Our 2006 21-EC mast collapses to the side. Anyone have ideas for supporting it during transport? We do day trips and always remove it for trailering.

I was surprised how EASY it is to remove for travel. That is what I tend to do for longer trips.

/david

 

[Stevan47]

Hi everybody: Glad the photos, which Dave posted, are of use to you all. Feel free to distribute them further if necessary. Hope they help. Regards to all. Steve

 

[daviduphoff]

Thanks for the pics. Our 2006 21-EC mast collapses to the side. Anyone have ideas for supporting it during transport? We do day trips and always remove it for trailering.

I was surprised how EASY it is to remove for travel. That is what I tend to do for longer trips.

/david

Ours too goes to the side. I can have the mast off our 21 in about 2 minutes. It fits perfectly on the mattress. Mind you we do not have radar on our mast. I once asked someone at Ranger about the support that came from the factory for it but never found an answer. We do have two brackets for the support, one on the mast and one on the cabin. Does anyone know what goes between them? I think it is safer to just remove it if you ask me.

 

[Stevan47]

Hi all: I have finally finished the prototype, travelling collapsible mast support strut for my R21. I will attempt to attach the photos this weekend so everyone can see it and copy as required. I will also add the dimensions. I manufactured it from HDPE cut-offs and bits and pieces. For those who do not know, HDPE is High Density Polyethylene, which is commonly used in the food manufacturing industry and also to manufacture water containers on larger vessels and on farms. Also it is used for chopping/slicing boards found in most household and commercial restraurant kitchens. Not cheap to buy but very strong, easy to work with and drill/form, using ordinary carpenters tools and drill bits. The beauty of this material is that it is not subject to weather conditions and lasts forever. I used stainless steel screws and strap hinge to complete the task. It comes in various colours but I used white, which looks good and matches the boat superstructure. I am sure it could be modified to suit larger vessels where the mast needs to be collapsed for towing/storage and where the original mast support strut is off-centre. Stand by. Regards to all, Stevan

 

[Stevan47]

Hi fellow Tug Nuts: Well, as promised, I have finally managed to attach the photos of my Mast Support Strut, for use when towing/travelling by road with the mast collapsed in the f'rd position. I have tried, in vain, to attach them to this post, but was unsuccessful, so I have inserted them into my Photo Gallery, where you will see some further shots of RHAPSODY under tow with the 'boat tractor'. Maybe someone can advise me how to attach photos to these posts - I must be missing something. Anyway, they are now in the Photo Gallery for all to inspect. I will detail the specifications below, for anyone who wishes to manufacture one for themselves.

The whole device is in three pieces (vertical strut, base pad piece and carry handle) manufactured from High Density Polyethylene (HDPE) and assembled using stainless steel components (screws and hinge). Dimensions:

Vertical, load bearing Strut: Length - 66.6cm (666mm); Width - 10cm (100mm); Thickness - 2cm (20mm).

Base Pad Piece (shaped for curvature of cabin roof and lined with white neoprene insertion rubber for non-slip contact with deck. Adhesive: SikaFlex 291 Marine): same stock material as above, but with a length of 25cm (250mm) and width of 8cm (80mm).

Longitudinal spine and handle (attached to main strut): same stock material, actual dimensions optional to fit, but in this model I have made it 57cm (570mm) in length and 4.5cm (45mm) in width.

I used 300 - 316 grade stainless steel countersunk screws, 10g x 1.5", throughout and used a 100mm, 316 grade stainless steel strap hinge to provide a swing joint connection.

The advantage of this support strut is that it supports the mast centrally, rather than from the side, as with the factory fitted stainless steel tubular support, thereby using the centre of gravity and being slighly farther f'rd, thus taking excessive strain off the cabin roof mounting screws and fibreglass canopy.

Have a look and let me know what you all think.

Cheers and Merry Christmas to all.

 

[walldog]

 

[walldog]

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[Stevan47]

Hi WallDog: many thanks for your IT expertise. Bless you. May you and yours have a great Christmas break. Kind regards, Stevan (RHAPSODY)

 

[Stevan47]

Courtesy of WallDog, here my attempt to attach the photos of my prototype Mast Support Strut, for use when travelling/towing with the mast in the collapsed mode. Regards to all

 

[SGIDAVE]

Very Nice Stevan,

Please correct or confirm my assumptions regarding your design:

It appears the baseplate is a "friction" fit and merely rests under load on the gelcoat. It is not fastened with screws, etc.

What connects the vertical support/mast with eachother? Is this too a friction fit? Or is there some sort of lashing? My concern is with bouncing down the roadway the assembly could dislodge with firm connection.

Merry Christmas,

david

 

[Stevan47]

Hi David: My apologies for taking so long to get back to you. Christmas was a chaotic event, as usual, and then I came back to work on Friday 2 Jan and have been real busy ever since. While at work this morning I went on line and saw your comments. Here we go:

First, yes, the base pad, with insertion rubber attached, is merely a friction contact with the cabin roof, held there by vertical force and also laterally retained, to some degree, by the action of the port and stbd s/s stays. The close tolerance of the base pad also prevents any lateral movement. No screws.

Second, as you will see (although maybe I did not show this well enough in the photograph), the top of the vertical support strut has a U-shaped/square section/slot cut out of it, with close tolerance, to accept the s/s mast when lowered. From recollection, the diameter of the mast strut is around 30mm and I was careful to only cut out enough for a close fit and also to completely envelop the tubular section. When placed into the slot, the s/s plate attached to the mast (used for mounting either Radar, SatNav or Windspeed Indicator, etc) also places downward, diagonal pressure on the whole assembly making it less prone to dislodgement.

You are right, though, in some respects, wrt possible dislodgement of the mast from bouncing under tow, if travelling over uneven surfaces. For this reason, I purchased some 'bungee cord' (elasticised rope-like material) and attached two white plastic halyard clips (called, 'Englefield Clips' in the Australian and British Navies and 'Sister Clips' amongst the civilian yachting fraternity: not sure what they are called in the US Navy though). Once lowered and in place, with the s/s stays secured, I then pass the bungee cord and clips through the top handle opening of the vertical strut and loop it over the back of the mast, then join the two clips together. If it is tight enough, this retains the mast sufficiently, with a little flexibility. Of course, if you wnat it to be rigid, you could use some good quality marine nylon cord in the same way. I have not towed the boat off-road or over any really bad surfaces, so I cannot say if this would be sufficient, but to date I have had no issues with the mast popping up out of the vertical support slot.

Hope all this helps. Let me know how you go and if you have any recommendatiuons for improved design/s.

Kind regards, Stevan

 

[fran uteg]

Hello Stevan47 I had the same concerns about the weight of the mast after I added the Furuno radar last year. The antenna was about eight pounds but with the arm that far forward I was concerned about the mast hinge. I built a support out of schedule 40 PVC and it has worked very well ...... I have the pictures in my photo album if you would like to see the finished product ....... total cost was less than $20.00 ........ hope this will be of some help 😉

 

[Stevan47]

Hi Fran: Will have a look at yours now, if I may. In the meantime, hope you approve of my design. A bit rough, but it certainly does the job. Will give you my appraisal of your rig when I have a look. KInd regards, Stevan