Forum thinkning hats on - dingy solution sought

Coming from an engineering background I would perhaps take a slightly more pragmatic view.

Although I am not aware of the specific components involved I would generally expect lifting equipment of any sort to have been proof tested at 1.5 times the safe working load and to actually have a factor of safety in excess of 2 and often fro construction lifting equipment more like 4-6 times the safe working load.

On this basis I would be relatively happy lifting the 220kg tender with the passerelle as long as it did not appear to deflect significantly.

However, as it is a retrofit it is equally possible that the supporting structure in the transom and swim platform are not suitably rated so I guess some caution will be required, but simple engineering view is if it looks ok it probably is, is things are flexing, creaking or showing any signs of distress then that is the time to worry.

The above is perhaps a bit cavalier and blase, especially without having seen or even looked at drawings of the components involved, but perhaps gives a different perspective that not much need be done to improve the current situation, even though it is technically out of spec.

Neil
 
Thank Neil.

If I try to lift the tender at full extension the ram gets so far then starts to collapse. It will lift it with the passerelle retracted halfway - 160kg limit is at full extension.

The other issue I have is the transom flexes under the compression force if the ram pushing the pass up
 
Flippant: feel the tubes with helium!!!

Serious, can you use the downward movement of the passerelle in conjunction with your pulley blocks to lift the dinghy?
 
jfm said:
Nick, do you have a link to your small high performance battery?
Click to expand...

"High performance" may have been a slight overstatement, as it's just a wet lead acid job, but it only weighs 10 kilos and has 420 CCA which is enough to start my Suzuki 50 comfortably, even with extended cables to the bow. It's also quite compact, so I could fit it through the bow locker round hatch by just unscrewing the hatch and easing a bit of GRP where the corners of the battery fit through.

It's a Varta B36, bought through Battery Megastore, who have an operation in France so can deliver to the boat.

http://www.batterymegastore.co.uk/varta-b36.html
 
Whitelighter said:
If I try to lift the tender at full extension the ram gets so far then starts to collapse.
Click to expand...

Does the tender get airborne before the 'collapse' and at what angle is the passerelle relative to the horizontal at this point?

If the transom is visible flexing then some strengthing is likely to be required, although it is likely to be a aesthetic (prevent gelcoat cracking, avoid people thinking it looks under strain) rather than a structural (likely to fail) issue
 
KevB said:
Flippant: feel the tubes with helium!!!

Serious, can you use the downward movement of the passerelle in conjunction with your pulley blocks to lift the dinghy?
Click to expand...

I'm not sure I get you there Kev - I'm probably being thick!!!
At the moment my best solution is to use the passerelle as a fixed gib arm with the blocks to lift the tender.

I currently have two three pulley blocks which I would have thought should reduce the force required to lift to an equivalent 40kg but it's not lift able by hand still. Even then at full extension the pass starts to sag once the dingy weight is fully supported by it. A suggestion has been to run cable up to an eye on the FB to support the pass during launch/recovery as it will retract with the dingy on no problem.

That still leaves the problem that even with the 6 pulley setup lifting it is hard work
 
Jez, I don't want to labour the point, but whilst the Yam 40 is no doubt a fine engine with the usual Yamaha build quality, it is by all accounts a bit gutless at low RPM, which is exactly where you need the power to lift skiers out the water. I've never had a boat with a Yam 40 4-stroke and swapped it for a 25 2-stroke, so I can't be sure of anything, but my gut feel is you'd barely notice the difference in terms of pulling skiers and ringos, and i'm certain you'd notice the difference from having 50 kilos less hanging off the back.

If you can't buy a new one through the commercial route (maybe someone on here can help?), then you could certainly buy a good used one and have it serviced/reconditioned. As you say, you'd get most of your money back by selling the 4 stroke.
 
I get you there nick, and it's an option complicated by:

Boat is in Spain
Getting stuff done in Spain is difficult.
Getting out boat out and then 40hp back is a grind.
Finding a 25hp 2 stroke

I think it's a very good back stop option. The boat currently tows a skier with no issues
 
Whitelighter said:
That still leaves the problem that even with the 6 pulley setup lifting it is hard work
Click to expand...

Friction can start to be a real problem with that many sheaves meaning the actual force you are trying to pull is closer to 50kg which is beyond most people. If you were going down this route, a chain hoist or lever hoist will be much easier to operate.
 
Whitelighter said:
I'm not sure I get you there Kev - I'm probably being thick!!!
At the moment my best solution is to use the passerelle as a fixed gib arm with the blocks to lift the tender.
Click to expand...

Ah, I assumed the blocks were anchored on the flybridge and you were lifting from there. My thoughts were to tie to the passerelle in the up position and lower it, lifting the dinghy with the pulleys.

OK, what about add another pulley to each of the ones you're already using. One end of the ropes on the passerelle the other anchored to to the bathing platform/transom, raise the passerelle and pulleys lift the dinghy?

bt3.gif


You add the benefit of spreading the weight further down the passerelle.
 
Last edited:
KevB said:
Ah, I assumed the blocks were anchored on the flybridge and you were lifting from there. My thoughts were to tie to the passerelle in the up position and lower it, lifting the dinghy with the pulleys.

OK, what about add another pulley to each of the ones you're already using. One end of the ropes on the dinghy, the other anchored to to the bathing platform/transom, raise the passerelle and pulleys lift the dinghy?
Click to expand...

I can see where you are coming from but cant visualise it. I get that if the passerelle can lift the rib using the blocks it reduces the force required (but increases the pull length) but I cant see how to do this AND use the passerelle to to support the dingy in the lift?
 
MapisM said:
Well, not much more I can tell you about that, really.
It was one of the earlier models, as I recall a 1999 Model Year, but moulded in 1998.
And without the optional stern crew cabin, which as I'm told is something that contributes to strengthening the stern overall.
Besides, I can't tell you how deep the cracks were, around the passerelle base.
According to the broker, they were only superficial cracks in the gelcoat (have you ever heard a broker telling that a problem is serious? :D), but they seemed rather worrying to me.

All that said, I would rather not use a F53 with a 400Kg ballast so far astern from the COG regardless of whether the passerelle can handle it... But that's me. :)
Click to expand...

The one I used to do also had no stern crew cabin and was a 1998.

A solution I did a couple of times on other boats was to upgrade the passarelle pump, and reinforce the stern.

In my experience I would move away from putting metal in the stern as reinforcement too, best is wood with bi-axial or tri-axial fiberglass and resin.
 
Nick_H said:
Jez, I don't want to labour the point, but whilst the Yam 40 is no doubt a fine engine with the usual Yamaha build quality, it is by all accounts a bit gutless at low RPM, which is exactly where you need the power to lift skiers out the water. I've never had a boat with a Yam 40 4-stroke and swapped it for a 25 2-stroke, so I can't be sure of anything, but my gut feel is you'd barely notice the difference in terms of pulling skiers and ringos, and i'm certain you'd notice the difference from having 50 kilos less hanging off the back.

If you can't buy a new one through the commercial route (maybe someone on here can help?), then you could certainly buy a good used one and have it serviced/reconditioned. As you say, you'd get most of your money back by selling the 4 stroke.
Click to expand...

I totally agree that the 25hp two stroke would probably perform better than the Yam 40, especially pulling people on toys. Combination of better smoother horse power and a lot less weight hanging off the transom.

If you want to save even more weight by replacing the battery, check out a Store like Demon Tweeks the Motorsport suppliers, they will have some very light yet powerful batteries.

Graham
 
Jez,

Assuming the ram is not leaking, have you checked if ithe passerelle actually drops overnight if you leave it level and say loaded with 150kg?
I like the engineering approach and I fully agree that with x3 security coefficients often employed, likely failure will be weakening ram seals leaking from one side to the other, or compressor need upgrading

Considering that a 15you passerelle ram will be V. near seal service time. I'd measure and order a new 30% bigger in wider ram and try it.
I bet a tenner it will slowly lift your rib as is

V
 
Hi vas,

Nope not tried it overnight. It doesn't drop with some one standing on the end.
Hadn't tough my about a leak or a service. If not too expensive that is probably worth doing.

Still the question of the flexing transom though.
I don't know how to go about strengthening it without hacking the crew cabin to bits. I'm guessing what it really needs is ply wood glasses to the back of the transom to stop the flex
 
Whitelighter said:
I get you there nick, and it's an option complicated by:

Boat is in Spain
Getting stuff done in Spain is difficult.
Getting out boat out and then 40hp back is a grind.
Finding a 25hp 2 stroke

I think it's a very good back stop option. The boat currently tows a skier with no issues
Click to expand...

This is the kind of challenge you get with having the boat overseas, unfortunately. I do think that Nick's 'swap the outboard' suggestion is by a substantial margin the easiest and quickest way to solve the problem. In your position I'd
1. buy the 25hp outboard here in the UK eg http://www.ebay.co.uk/itm/Yamaha-25...554525?hash=item2cb0031add:g:xcgAAOSwIgNXly8U
2. put it in the car
3. drive to Spain - although it's a fairly long way you could actually do it in one long day through the tunnel, straight down the middle of France and turn right when you hit the sea
4. the new engine only weighs about 50kg so you can just carry that on to the boat
5. use your passerelle or crane to lift the old engine off and the new engine on
6. get some local help to get the 40hp off the boat and into the back of the car
7. drive home
8. sell the 40hp on ebay and in all likelihood make a small profit

Depending on how hardcore you're feeling, you could easily do this in a long weekend. In practice you'd probably wait until there are other things that need to go to the boat and make a car load - or alternatively use one of the small transport companies that run vans up and down to the UK to transport it. No idea for Spain, but to SoF (about 200m less) it would be about £100 each way.
 
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