Installing boat lightpole

spartacus · 09 January 2013, 12:54

I'm just about to order a lightpole made in 1 1/4 marine grade stainless steel tubing to my own design, 6' high (from transom) which is collapsible (Protex catches). The base will have a flange or base plate which can be secured to the transom. If you look at this picture of my Ribcraft 4.8m - it will be placed on the right hand side between the transom leg and sponson tube.

What are your thoughts regards installation. The transom is 50mm thick. Can I get away with pre-drilled holes and use 4-6 40mm self-tappers countersunk, or is this really a bolt-through-transom job, sikaflex, etc.

The lightpole (which will also be a mount) for my Metz antenna will weigh roughly 2.5kg.

Thanks for any advice!

jyasaki · 09 January 2013, 15:30

6 lbs, 3/4 of which is up high and unsecured, plus the weight of the installed lights and antenna. Decent amount of penduluming mass, all transmitted to the anchor point.

I would say bolt through with a backing plate. Then again, I tend to design things so they're bulletproof.

jky

PeterM · 09 January 2013, 15:49

Quote:

Originally Posted by jyasaki

6 lbs, 3/4 of which is up high and unsecured, plus the weight of the installed lights and antenna. Decent amount of penduluming mass, all transmitted to the anchor point.

I would say bolt through with a backing plate. Then again, I tend to design things so they're bulletproof.

jky

+1 ...maybe stick some horizontal tube across the bolt holes (inside the tube) to stop the tube crushing (I've not eplained that well I don't think)

spartacus · 09 January 2013, 16:14

Quote:

Originally Posted by jyasaki

6 lbs, 3/4 of which is up high and unsecured, plus the weight of the installed lights and antenna. Decent amount of penduluming mass, all transmitted to the anchor point.

I would say bolt through with a backing plate. Then again, I tend to design things so they're bulletproof.

Thanks jyasaki. The Metz antenna is really lightweight, and the 12v LED light is too, but I take your point about the lightpole being high and unsecured and bolting it is probably the best way to avoid having to do remedial work after installation. I can use stainless steel penny washers for the outside of the transom.

Dhf · 09 January 2013, 16:15

Depends really on how big the base plate is, if it extends the full height of the iner transom I would be tempted on the self tappers, If the base plate is only 4 or 5" high, then I would also put a s/s U bolt above the plate, I would have thought that should do seeing its a lightpole not a lean too.

Downhilldai · 09 January 2013, 16:18

Bolt through the transom. Someone may grab hold of the pole to haul themselves in from the water and end up ripping the self-crappers out.

spartacus · 09 January 2013, 16:27

Quote:

Originally Posted by PeterM

+1 ...maybe stick some horizontal tube across the bolt holes (inside the tube) to stop the tube crushing (I've not eplained that well I don't think)

Cheers Peter. Hightower did this with his lightpole - which I've used as part of my specification with the manufacturer. This looks pretty robust don't you think?

Original thread here: http://www.rib.net/forum/f37/boat-li...s-45076-2.html

9D280 · 10 January 2013, 14:22

+another for the throu bolting. I built an extension pole for my A- frame to get proper 1M sepration..... I'm now on my MK3 pole.

As you appear to have an eye screwed into your transon knee, could you through bolt that on the opposite side? Means your transom has one (or 4) less hole(s).

treerat · 10 January 2013, 17:30

If you plan to take it off for storage etc why not have it with a G clamp type thing over the top of the transom?

No holes at all then

Downhilldai · 10 January 2013, 18:16

Quote:

Originally Posted by treerat

if you plan to take it off for storage etc why not have it with a g clamp type thing over the top of the transom?

No holes at all then

spartacus · 10 January 2013, 19:45

Quote:

Originally Posted by treerat

If you plan to take it off for storage etc why not have it with a G clamp type thing over the top of the transom?

No holes at all then

You're not a million miles off the mark with your suggestion.

It was an MOD light pole that gave me the original idea. It used a thumbscrew device which could be tightened. However it also had an alloy pin which locates in the transom to stop the light pole moving from side to side.

Because the light pole can collapse (Protex catches) I don't mind the lower section being bolted on permanently.

treerat · 10 January 2013, 20:05

Quote:

Originally Posted by Downhilldai

It's not that bad an idea - I've seen it done!!!

Festinghouse · 10 January 2013, 20:23

im about to make a fold down white light - im using a stainless ratchet mount (for vhf aerial) as the base of the light. sturdy and easy to fold down

spartacus · 10 January 2013, 20:46

Cheers Downhilldai. I'll bolt it on as suggested. I hadn't thought about someone grabbing it, but i can see it makes sense for it to be fitted securely.

Thanks 9D280 regards bolting through the transom knee - I hadn't actually considered that.

I thought it might interfere with the steering arm on the Twatsoo at full lock, but it doesn't. Just tried it, so far, so good. What about the actual area for mounting? The transom knee measures 11" high x 11" deep x 2" wide. What are your thoughts regards the mounting plate? If I use the transom knee (area between tube and knee) and get a plate made that fits the area with 4 mounting holes and the lower section of the light pole welded so when fitted rests against the transom?

Downhilldai · 10 January 2013, 21:05

You could use the transom eyebolt and have a separate bracket at 90 degrees, lower down, fixed through the transom knee.

spartacus · 10 January 2013, 21:38

That could work Downhilldai.

Here's another picture of the transom knee from a different angle. I'll need to check how much available thread there is on the transom eyebolt, or simply loose the penny washer that's on it which would be replaced with the flange/fixing plate from the light pole.

Downhilldai · 10 January 2013, 22:49

If you need to, get a longer eyebolt - they're not expensive and you can re-use the original somewhere else, I'm sure.

Use loctite on the domed nut, if you re-use it, as there's no nylon in them and they can work loose.
A button head bolt would look good through the knee.

simon23 · 10 January 2013, 23:06

Quote:

Originally Posted by Festinghouse

im about to make a fold down white light - im using a stainless ratchet mount (for vhf aerial) as the base of the light. sturdy and easy to fold down

I made one like that a few years ago,worked well till i let it folded down over the winter and it filled with rain water through the drain hole and light fell apart.good luck with it

9D280 · 11 January 2013, 14:50

Do you even need a plate to secure to the knee? Would a U- bolt of an appropriate diameter just clamp it solid?

Downhilldai · 11 January 2013, 15:19

Quote:

Originally Posted by 9D280

Do you even need a plate to secure to the knee? Would a U- bolt of an appropriate diameter just clamp it solid?

No, the pole would/could turn and the knee would need twice as many holes in it.

Twood also resemble a bit of egzost.