Safe way to support a motorboat for short distance moves?

[baylabayla3288]

There seems to be many different equipment in use for moving boats within marina yards. Some approaches looks very risky my view. In particular some hydraulic trailers seems to support the hull only on 3 points where the stern is supported by pads against the bottom panels without keel support.

http://www.youtube.com/watch?v=qHseo-6_eo0&feature=youtube_gdata_player

The above Roodman has large pads but it could still crush a lifting strake or a sensor

What is your experience, safe or not? Could this cancel the hull warranty?

 

[Bandit]

The Roodberg trailer in the Video is a 47,000 kg capacity trailer and the boat is probably about 25 ton displacement.

The trailer in question is using 6 pads on hydraulic rams ( three each side ) to support the rear end of the boat, ie in the area of the engines and fuel tanks where the weight is, the bow is supported on the keel on the movable beam. so it is in fact supported on 7 points in total.

I have been involved in operating a considerably smaller 15,000 kg Roodberg trailer for donkeys years that only has one pad each side and the movable beam at the bow we have only had one problem which was with a clinker built wooden boat and I must admit the ones that concern me are wooden boats.

You can also mount a cross beam at the back of the trailer.

 

[MapisM]

we have only had one problem

Trouble is, you NOTICED only one problem.
I'm not saying that plenty of other boats were damaged of course, but I'm aware of GRP hulls where cracked stringers and/or frames were only found upon close inspection - typically when surveyed.
For instance, I wouldn't be happy at all about the overhang astern of the Hatteras in the video, even if the heavier part (e/r) looks well supported.
Anyway, fwiw, there's only one way someone could lift my boat with that system: over my dead body.

 

[Bandit]

They are pretty well boatyard industry standard for boat moving in a yard after a hoist out as well as in the video slipway lifting from the water.

Consider also that a boat hoist only supports a boat on two slings?

 

[MapisM]

Consider also that a boat hoist only supports a boat on two slings?

Nope, any decent hoist capable of handling a 50 footer has 2 slings for each cable, i.e. 4 in total.
And I've seen bigger hoists with 4 cables, capable to handle up to 12 slings...!

 

[Deleted User YDKXO]

Trouble is, you NOTICED only one problem.
I'm not saying that plenty of other boats were damaged of course, but I'm aware of GRP hulls where cracked stringers and/or frames were only found upon close inspection - typically when surveyed.
For instance, I wouldn't be happy at all about the overhang astern of the Hatteras in the video, even if the heavier part (e/r) looks well supported.
Anyway, fwiw, there's only one way someone could lift my boat with that system: over my dead body.

Agree with you. I would be very unhappy about having my boat lifted with that thing. Firstly you have to rely on the operator to adjust the 2 legs precisely so that the support pads sit flat on the hull rather than on a chine or spray rail. Second you rely on each of the pads supporting the hull to be loaded equally. Third you rely on the truck driver being careful about driving over bumps such the boat doesn't bounce on its supports and fourth you rely on the truck driver not driving around a bend too fast such that the boat tilts on its supports or worse tips over. I would be slightly happier if the boat was tied down during movement but IMHO a hoist with slings is a much safer way of lifting a boat and moving it around

 

[baylabayla3288]

Thank you for your comments. The reason for posting this question is that I was approached by a boatyard that offered interesting pricing for winter storage but they use a Roodberg type of hydraulic trailer to transport the boats a few kilometers ashore. I decided to stay with my old boatyard who is using a sling based system (Sublift). The debate is however still ongoing. My view is that there is simply too much that can go wrong when using hydraulic trailers without proper keel support and the damages are typically hidden. Larger boats are designed to be supported on the keel and the side supports are only keeping the boat upright as the bottom panels are not strong enough to carry the weight of the boat. It would be interesting to hear a boat manufacturer's view (Fairline in my case).

 

[Bandit]

Nope, any decent hoist capable of handling a 50 footer has 2 slings for each cable, i.e. 4 in total.
And I've seen bigger hoists with 4 cables, capable to handle up to 12 slings...!

It depends on the weight of the fifty footer the 75 ton hoist we work with has a capacity of 25ton per sling so a 25 ton boat and two slings is normal, and well within capacity.

The twin slings per carriage or block are fairly close together about 25 inch centres, so don't spread the weight much.

One of the problems with a hoist is where you can lift a boat considering position of shafts, keel, stabilisers, exhausts, water outlets, logs, sounders, windows and of course in relation to all of these the probable position of the longitudinal centre of Gravity. The weight split between sling sets should be within 10 per cent. Most production boats that have "Lift Here" stickers which are positioned miles out of where they should be ref LCG probably because the manufacturers hoist does not have a weights display for each set of slings.

We are really talking about two different things concerning a Roodberg Trailer as shown :

1/ Moving a boat from a Boat hoist to park it some distance away, where it can be parked more efficiently using a hydraulic trailer or in a position where a hoist cant get to ie parking them closer than a hoist can, a distance away where a hoist cant get to say over a road etc or inside a shed where they are stored over winter. Hoists cant place boats very loosely in a yard side by side, so are not very efficient for space use if it is at a premium.

2/ lifting a boat from the water or re launching a boat into the water from a yard up or down a sloping slipway and then moving it around a yard and placing it in a cradle or on blocks.

My personal preference for my boat 48ft 18.5 tons would be a Hoist and then park with a trailer.

For an operator a slipway and a trailer is cheaper to set up than a hoist and trailer.

I have lifted boat with a crane and spreaders for many years in the past and that is something that gives me the hee bee gee bees and can stain your underwear ! Give me a hoist any day.

I think you will find that most production boat builders use these trailers or similar at their factories.

 

[MapisM]

My personal preference for my boat 48ft 18.5 tons would be a Hoist and then park with a trailer.

Bingo.
I wasn't objecting to the trailer per se, it's rather its usage for lifting the boat that I don't like and I wouldn't trust.
In fact, my 53' boat (with her 35T of pretty thick timber!) is regularly moved around in my yard with the trailer below, before storing her inside the shelter, for the very good space optimization reasons which you mentioned.
But driving the trailer under the hull, and positioning it carefully after the boat has been lifted by a hoist, that makes a huge difference vs. the procedure in the video.

Btw, while I accept that two 25T slings for lifting a 25T boat is safe enough in terms of capacity, I definitely prefer the twin slings per carriage normally used at my yard.
Aside from the fact that one sling failing, extremely rare as it can be, is not totally impossible, I would disagree with you on the weight spreading difference.
True, the twin slings per carriage are rather close each other - though IIRC they are more like 2 feet, if not a bit more, in the 80T hoist I'm talking about.
But it does make a difference to have the load distributed over a given surface, rather than half of it.
I mean, I'm sure you wouldn't want to use a steel cable instead of a sling, would you?

 

[Bandit]

Mapism

The trailer in your photo looks like an Abi and it appears to be supporting your boat on the keel at the bow on the crossbeam and on three hydraulic pads on each side.

The principle is the same as the Roodberg ie a "U" shaped trailer with a cross beam and hydraulic adjustable width to bring in the side beams in or to move them out. The Abi as some of the Roodbergs is all wheel steer.

The trailer needs to be "U" shaped as when you place the boat over keel stands to store the boat ashore and lower it and then place the side stands you need to have these in place before you lower the trailer and move it out.

No trailer can support the boat along the length of the keel and place it on stands and then move out the trailer from under the boat, the boat would have to be lifted off the trailer with a hoist or crane therefore making poor use if space.

 

[James L]

I don't have a photo of it, but in the boatyard I use, the hoist puts the boat straight onto the stand.
The trailer then picks up the stand for moving the boat around so it is fully supported the whole time.
Also seems a lot simpler and probably cheaper than the trailers pictured above.

 

[MapisM]

No trailer can support the boat along the length of the keel and place it on stands and then move out the trailer from under the boat

I see what you mean, but the trailer also has a removable crossbeam (or maybe two, can't remember for sure, and I don't have any pics showing that), which are detached after putting the boat on stands to pull out the trailer.
This way, it's the keel which always takes most of the load, and the hydraulic pads are only meant to keep the boat from listing.
Of course, the whole movement area plus the shelters are nicely flat - I wouldn't want to see the boat on that trailer in anything else than a perfectly horizontal position.