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Old 16 October 2016, 11:17   #1
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keel height on a trailer

Is the any reason I shouldn't try and get the keel as low as possible on the trailer?


I've previously been told that the boat should be high enough off the ground that, if the engine should swing back down it won't hit the ground.

I'm tempted to get it as low as poss as it'll lower the centre of gravity and also make launch/recovery easier ( I has to use 20 m of rope and a lot of pushing at Warsash on saturday)
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Old 16 October 2016, 12:46   #2
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Low is good - but you MAY discover that the front of the keel will strike some of the axles/crossmembers when recovering. If so, some carpet or extra rollers will help.

Trailers are a curse!
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Old 16 October 2016, 12:58   #3
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I prefer mine as low as practically possible as long as your careful and don't forget to trim up before you leave you'll be fine
Although I did have a pal who had a waterski slide over and activate the trim switch mid journey which ground the skeg down pretty good
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Old 16 October 2016, 14:10   #4
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Quote:
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Low is good - but you MAY discover that the front of the keel will strike some of the axles/crossmembers when recovering. If so, some carpet or extra rollers will help.

Trailers are a curse!
+1
I've got heavy rubber fendering from the back an HGV trailer fixed to the top of the axle with BIG cable ties. Keel sometimes touches it but with engine trimmed out I can drive the boat right up to the snubber, lean over the bow and clip on to the trailer. Makes launch & recovery so much easier.
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Old 17 October 2016, 05:05   #5
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Yes low down and as far apart as you can get them to give the boat best support
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Old 17 October 2016, 07:41   #6
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be VERY careful changing anything on your trailer.

i damaged my brand new keel first time recovering due to a poorly setup trailer.

if you change anything then get carpet everywhere to stop taking chunks out the gel.

Unfortunately i can't reach my bow eye by leaning over so if you can do this that in itself would be of use.
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Old 17 October 2016, 10:40   #7
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Be careful of your fender (or worse, bare tire) rubbing on the tube bottom. That's usually the determining factor in how low you can sit the hull (at least in my experience.) Aside from that and the skeg problem (I use a motor support; takes that one out of the equation), lower is generally better unless you have really uneven roads to travel.

When making changes, remember that launching and recovering puts the trailer in a nose-up attitude compared to the hull. Your first contact point will be deeper than how the hull sits on the trailer out of the water.

jky
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Old 17 October 2016, 12:38   #8
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Be careful of your fender (or worse, bare tire) rubbing on the tube bottom. That's usually the determining factor in how low you can sit the hull (at least in my experience.) Aside from that and the skeg problem (I use a motor support; takes that one out of the equation), lower is generally better unless you have really uneven roads to travel.


jky
I noticed when I was into hard boats that the wider trailers that your laws allow meant that the boat chines could sit lower between the wheels whereas ours needed the boat to be set above the wheels. We have been given and extra 3 inches recently but "EU type approval" still has us using 1940's style rod operated drum brakes.
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Old 17 October 2016, 12:45   #9
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Unfortunately i can't reach my bow eye by leaning over so if you can do this that in itself would be of use.
I fitted and extra bow eye set where I could reach it.
Almost crippled myself climbing over the front of PM's Ribeye onto the trailer on Saturday to get at the bow eye that's set so far back under the bow of the boat.......nightmare.
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Old 18 October 2016, 06:21   #10
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Unfortunately i can't reach my bow eye by leaning over so if you can do this that in itself would be of use.
Is it worth extending your winchpost vertically then so you can attach a short line to it, to hold the boat in place, and then connect the winch to the eye from the outside?
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Old 18 October 2016, 07:13   #11
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tbh buddy it is a juggling act as i normally need to recover on my own. my wife can't drive and the rib is just big enough to be a pain to solo recover.

i keep saying i will get a leccy winch so my mrs can hook it on and press a button whilst i drive it on as far as possible.

with my back wheels of 4x4 touching water i can't drive the boat on to the snubber on 90% of slipways i use, i can only get about halfway and need to winch in the rest. my mrs can just about winch it in to the last 1ft at which point i can clamber over bow onto the trailer (it is quite high the old 6.8 at the bow)

i am out with last tango quite a lot and his is 10x easier than my own, also helps his mrs can drive it after he hooks it on.
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Old 18 October 2016, 10:28   #12
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I noticed when I was into hard boats that the wider trailers that your laws allow meant that the boat chines could sit lower between the wheels whereas ours needed the boat to be set above the wheels. We have been given and extra 3 inches recently but "EU type approval" still has us using 1940's style rod operated drum brakes.
Not so much the trailer laws as how the hull is shaped, hard boat vs RIB.

Hard boats are narrower towards the keel, which allows them to sit down between the fenders or wheels (or both), with the keel/axle/crossmember interaction limiting how low you can go.

With a RIB, there is much less taper (i.e. the hull is a flatter form) as you move from the tube to the keel, which means the boat has to sit higher at the keel to allow the tubes to clear the wheels.

jky
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Old 18 October 2016, 10:34   #13
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Tubes clear the wheel? Not sure I follow, never seen rib tubes close to the wheels before? I am sure it is possible but I've not seen it personally.
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Old 18 October 2016, 12:36   #14
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With the 25 degree deep V hulls it's not an issue but when I had the SeaPro the mudguards/fenders was the limiting factor. I had basically set it up so as the tubes were only about an inch clear of the mudguards.
Could I have got away with it I'd rather have had it even lower.
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Old 20 October 2016, 10:00   #15
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Tubes clear the wheel? Not sure I follow, never seen rib tubes close to the wheels before? I am sure it is possible but I've not seen it personally.
http://www.rib.net/forum/attachment....3&d=1151960919

(first image in the Show us your Rig thread) Note how the tubes have to sit above the fenders.

Compare that to a similar sized hard boat (sorry, forgot how to inline the image, so see attachment):
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Old 20 October 2016, 13:06   #16
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Originally Posted by jyasaki View Post
http://www.rib.net/forum/attachment....3&d=1151960919

(first image in the Show us your Rig thread) Note how the tubes have to sit above the fenders.

Compare that to a similar sized hard boat (sorry, forgot how to inline the image, so see attachment):
Can't quite make out the photo but I'm guessing Bayliner.
Even that boat on a UK trailer probably wouldn't drop between the fenders.

I've been there, as I said my last RIB (Seapro 520), the mudguards were the limiting factor with the boat almost sitting on them.
As an "aside" I've always fitted mud flaps to my trailers, I have the fear of something sharp throwing up of a tyre and bursting a tube because I've seen the back underside of tubes covered in mud sprayed up off the wheels..
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