Converting a trailer for bilge keeler

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davidbfox

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I've acquired a trailer designed for a shallow fin keel but I want to use it as a yard trailer for a bilge keel Snapdragon 747. This is a heavily built 24ft yacht. I've removed unnecessary supports. Don't have exact keel spacing or measurements until the boat is removed from the water!

I need to put a deck onto the trailer for the keels to stand on. There are cross members about 1 metre apart that I can attach to with u-bolts.

Suggestions for material for deck please
- timber?
- aluminium checker plate like fire escapes (is this strong enough?)
- steel sheet (what thickness? Rusting?)
- some sort of mesh?
- some purpose made channels with guides on?

What is recommended and where can I get it please?
 
My trailer was made to take both shallow fin keel and bilge keels, bilge keel was a 19 ft light boat and the platform the bilge keels rested on was 3/4 inch ply, only used bilge keel boat for one year, but over the years have replaced the ply twice, makes a handy tray to lay tools on, but I would recommend looking at other materails other than ply.
Can send you a photo if that would help,
 
How about a couple of 5" or 6" wide steel channels? Lengths available from steel stock-holders, fabricators or scrap yard. Make them long enough to span your cross-members, and adjust spacing and angle the first time you load the boat ??

A bit like the rusty bit in the bottom right here (ignore the woodwork and the hovering boat).

422517284_a30d42a363_d.jpg


FWIW I think you need a positive 'stop' to erm... stop the keels slipping sideways or forwards.

Andy
 
I built my own road trailer for a small bilge keeler.

Typically the channels used for car transporters were used for the keels but in my case since the load is distributed across four cross members as well as the back and front of the basic 5ft square frame I used some light channels (which were to hand) made of sheet steel. I guess no more than 2mm thick, probably less.

There is some merit in using wood but I would use some decent planks eg scaffold planks or heavier rather than ply.

I would not worry about guides for the keels, If you are going to use it for launching and recovery you wont see them anyway so what you need are docking arms that are quite substantial, which come up well above the deck and which will allow you to accurately position the boat when hauling out regardless of wind and tide effects. It is best if they are removable for convenience while working on the boat ashore. One pair is just adequate but two pairs will be miles better.

Our boat yard uses old "bomb trolleys" which are long and narrow with smallish diameter wheels, one pair steerable They put several timbers across the trolley for the keels to stand on. One pair of docking arms clamp onto one of the timbers when hauling out. However they remove the boats from the trolleys once ashore which you presumably won't be doing. Mostly they only lash the timbers in place to stop them floating off except for the one with the docking arms attached which clamps in position.

There are trailer centres around which may be able to supply suitable steel channels but I am not sure that home construction of road trailers is even allowed now so they are not as common as they used to be. Steel is relatively inexpensive from a steel stockholder. See your Yellow Pages.

If you are converting a road trailer it will be best to remove all the old braking system. It would also be better not to have any suspension but that will not be so easy to remove.

Seal off any hollow sections with some old engine oil inside.

If this trolley is to be used in a commercial yard then talk to them. Our yard much prefer to use their own trolleys even though it means loading and unloading the boats every time they are moved. They also dislike all the empty trolleys getting in the way during the summer.

Determine whether your boat will stand on just its keels especially when tipped backwards a bit on a slip way. If it normally also rests on the rudder and or skeg as well you may need to lash the bow down to the front of the trolley.
 
IMHO .... scaffold planking to create a total bed.

If you intend to use the trailer to launch / recover the boat - then at front edge where keels stop - a block either side to have keels butt to. IF you really want to be fancy and clever ... make the stop from two blocks either side formed into a V for the keel to self centre and locate to. But you'll probably have to sort this after boat is out of water - unless you know another 747 you can measure up ?

Docking arms either side are great to help align boat on trailer - but often are not strong enough in a wind ... so a trick is to cross two ropes just aft of the keels and lead up to the sheet winches - the ropes are marked so you keep same lengths each side ... (suitable protection on strake of course) ... wind them up and as boat settles keep winding in so boat sits into the V of the ropes centred ... with it being up against fwd stop of course.

My Snapdragon 23 ... I used to use the boats motor to "drive" the trailer up the slip so the boat settled fully against the stop etc. ... another used to be in the Land Rover with long rope to trailer ... as trailer moved - he kept rope from going slack .. and once boat had settled - the LR held all. Lash up and then tow away ...
 
vics is absolutely right about having substantial docking arms, I am going to use removable scaffold poles and am using two lengths of angle iron per side with something like scaffold board bolted between to support each keel. what does vic use for docking arms?
 
[ QUOTE ]
what does vic use for docking arms

[/ QUOTE ] Vic's boat is always launched and recoverd on one of the boat yard trolleys except for the rare occasions that it is craned in or out off or onto its road trailer.

The docking arms on the yard trolleys are lenghts of something like 4x3 (timber) at a guess. They are mounted in holders that clamp onto the timbers on the trolley. They are adjustable to suit different boats. The yard functions on a budget that approximates to zero so nothing is at all fancy.
 
Ultimately you will need steel channel for the keels as with a ply deck you won't be able to paint antifouling on the hull between the keels.
For A/f ing the keel bottoms you might consider cutting the channel into 3 parts then bolting down so they mate in line. When the time comes you can remove each section individually to paint the bottom of the keel then refit the channel.

When you are hauling out the boat you need to remember that the trailer will not be horizontal (level fore and aft) as it will be on a sloping ramp however the boat will be level. This aspect causes all sorts of problems especially at the bow. On our club (fairly steep) ramp on a boat your size the bow will start about 2ft lower than the final location when the boat is on the trailer. This causes problems if you have a post at the front with an attachment to the bow.
One answer is to hold the boat onto the trailer (forward) with ropes from each side that attach to the hull well back a bit like springer mooring ropes. Any front post on the trailer needs to be well clear to allow the bow to rise and fall.

As said guide poles at the back of the trailer are almost essential to ensure the boat is centred on the trailer. Remember that because of the slope of the trailer the keels will not be in the channels at the back until you actually haul it out of the water when it will settle.

For the first try of the set up you will need a mask and snorkel and be prepared to get into the water to look at the boat on the trailer before hauling.

I imagine you will have to let the trialer down into the water on a rope from the vehicle because the tow bar will not be long enough.
Make sure you have a stout jockey wheel to support the front of the trailer. You might also need to be prepared to stand on the draw bar to hold the bar down if the boat is balanced to far aft.
For road towing you need about 100kgs load on the draw bar. This is still a good aim even for a yard trolley.

So good luck and be prepared to be forced to abandon the retrieval initially to enable trailer modifications. It is very satisfying to be able to do it yourself. I help a friend each year diy with a fin keel but it can be traumatic. At least for first few rerievals. olewill
 
Just another thought. If you have iron keels then either use wood or have wood supported by steel if you will be hauling out on a steep ramp. Iron keels on a steel support can slide !
 
Thanks - massive knowledge out there! I think I'll try to source proper channels, maybe after using scaffold timber first time to get the sizes. Not too keen on snorkelling but hope to have the help of a friendly tractor driver.

On lakesailor's http://www.lakelandimages.co.uk/keels/ : Could the green boat be a Snapdragon that overwinters in Ferry Nab car park? Minty Weasel?
 
I'm in the final stages of a trailer/ launch-trolley combination build.

Box section was used for the launch-trolley frame, which was welded-up and then pressure-tested by super-gluing a tyre valve over a small hole, which was welded-up after testing.

The bilge keels sit on ladder sections made from heavy angle, with 'rungs' in pairs, on top of which are fitted rubber pads made from old car tyre tread.

Many ways of skinning a cat ....

Colin
 
Why do you want it to be a sealed frame? If any damp should get in it'll do it's work unhindered.
Wouldn't it be be less liable to internal corrosion with open tubes which drain after immersion.
 
[ QUOTE ]
Why do you want it to be a sealed frame

[/ QUOTE ] Vital if the trolley is to be used in saltwater but probably not if, as is the case with this one, it is for use in fresh water. A spray through with Waxoyl would be good idea and adequate.
 
Sure - two different approaches can be adopted with dunkable trailers: one is to use freely draining open section steel - the other is to use box section and ensure that water never gets inside in the first place ...

One significant advantage of a trailer-trolley combination is not getting the trailer road-wheel bearings or brakes wet (and thus corroded from salt water), but unfortunately there is an additional weight penalty of a couple of hundred pounds. My rationale for using box section for the trolley frame is that relatively thin wall (3mm) box section imparts far greater strength and rigidity than the equivalent weight of open section.

If you decide to use channel section to support your keels, do ensure that they can drain ok - I've seen channels corrode and eventually disintegrate when rainwater has been retained there by fallen leaves and other debris.

'best
Colin
 
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