Alternative to A-frame

Iron Dials · 23 November 2016, 12:58

HI Folks,
So I've got a question.
I'm considering removing my A-Frame.
It's a basic single tube affair, and while it supports the VHF aerial and the nav lights it gets in the way of mounting an aux engine directly on the transom.

SO.....

I was considering removing it and replacing it with an upright stainless or carbon fibre structure on one side. Probably 3 "poles" attached to a single mounting plate using existing mounting holes for A-frame. The multiple poles to give it some rigidity, possibly different weights/diameters to reduce resonances (if that's the correct term)

The plan being to mount the lights and aerial onto this while freeing the other side of the transom.

Has anyone tried this?
Are there any pitfalls?
Any design ideas already floating about?
The whipping due to motion/weight is my concern.

Maybe it's a non-runner but I reckon it might be at least as cheap as properly fitting bracket for aux, assuming I get it fabricated locally.

Ideas on a postcard......

Thanks

willk · 23 November 2016, 14:33

M. Thornton has one on his Scorpion. It looked pretty rigid.

Iron Dials · 23 November 2016, 15:59

I was looking at a much smaller footprint.

Spent last half hour looking at carbon fibre projects on Instructables, dangerously and naively optimistic.

jwalker · 23 November 2016, 17:09

Quote:

Originally Posted by Iron Dials

Ideas on a postcard......

Put a frame over your console. If you're creative there's lots of pluses to that.

Bluerib · 23 November 2016, 17:13

I have a single light pole made from 50mm stainless steel. It drops into a bracket mounted on the outside of the transom and is secured there with a bolt. Wiring for the Radio Aerial and Nav lights is just long enough to allow the pole to be carried inside the boat in transit, or while boat cover is on. It is very rigid - never had any problems with it and it leaves the other side of the transom clear for a boarding ladder. It was supplied by Ribcraft as part of the initial build, but I'm sure any s/s fabricator could put one together.

Xk59D · 23 November 2016, 17:43

you see plenty of single poles on the transom that would look good and should be fairly easy to make.

there is also something like this which may give some ideas- NAVISAFE | Navisafe Dinghy pack – Inflatable

Force 4 12m Combination Nav Light (Blk) (100038A)

Tim M · 23 November 2016, 19:13

Quote:

Originally Posted by Xk59D

you see plenty of single poles on the transom that would look good and should be fairly easy to make.

there is also something like this which may give some ideas- NAVISAFE | Navisafe Dinghy pack – Inflatable

Force 4 12m Combination Nav Light (Blk) (100038A)

A friend of mine has one of those Navisafe poles fitted to a Ribtec 585. Works well for the occasional night out.

Iron Dials · 23 November 2016, 19:20

Thanks for all the suggestions so far.
I was planning to re-fit all the existing lights, aerial etc permanently onto the new "structure" so you've given me lots of starting points to work from.

JWalker, your suggestion is very appealing. T-Top shouts out at me.
I've always had a concern re windage if I build a frame around the console, but the prospect of shelter, well that's just very, very tempting.

spartacus · 23 November 2016, 20:26

Anything is possible. I had a bespoke lightpole made that could house a single LED all round stern light, Metz antenna and a red ensign!

Because the boat is garaged I didn't have the height for an A frame, plus I wanted to fit an auxilliary engine. Result, 3-part stainless steel 316 with fastening latches, bolted to the transom knee. Can be dismantled for storage.

I fitted the main navigation lights up front on the side of the console.

Red Fox · 28 November 2016, 19:30

I fitted three of these through the transom in vertical line and a 1"x 1.5m stainless pole with a metz connected with a salty johns adapter. The pole fits tightly but is removeable so that it all goes in the garage. Seems to work a treat.

Red Fox · 28 November 2016, 19:39

metz adapter

9D280 · 29 November 2016, 23:09

I have a similar problem, and when life lets me, my plan is (currently, this thread is chucking curveballs at me!) top replace my "goalpost" frame with one that curves out over the toobs., thus freeing space for the Aux.

Iron Dials · 30 November 2016, 08:50

I've seen some pretty narrow towers on Brig ribs which might be worth consideration although the suggestion of a single rod (I'm thinking carbon fibre) is probably where I'll go, just need to be sure a single rod won't whip too much

Thanks for all the ideas.

gtflash · 30 November 2016, 19:05

My alternative to a an frame. Originally born out of a thread like this. Made originally by a fellow ribneter out of 50mm dia carbon pole. It's now been reinforced with carbon at both top and bottom joins. 2k car paint and then laquer. If I was to do it again, I'd have a stainless footplate and head on the carbon pole. Spent far too long sanding, painting the join between carbon pole and carbon foot and head plates. I haven't used he boat with it yet, but regularly grab it to pull myself uP