Setup a Quintrex Dart on a Dunbier Trailer

[sandman55]

Hi all I have recently bought as a package, a Quintrex 355 Dart (3.64 Metres long) with a Yamaha 9.9 hp 4 stroke on a Dunbier Nipper trailer with 13 inch wheels the one with the short skids that can pivot see here http://www.dunbiermarine.com/popup/nipper_4M_13s.php

I would be interested to hear from anyone who has this setup or has knowledge of them.

I have only launched this boat 3 times and each time I have had problems because the keel which is extruded aluminium in a "I" pattern or you could say a "H" pattern rotated 90 degrees. The back part of the keel on the quintrex is partially cut away which is supposed to help with manoeuvring the boat in the water.

The back and centre rollers are now the hard blue plastic and the front one that doesn't do much is rubber.

Originally all the rollers were up hard against the keel which meant when I launched the back roller would run on the cut away section and when it got to where the keel was not cut away the boat would be gradually lifted almost 30mm higher which would clear it from the side skids and the boat would tip onto one or other of the skids and the bottom flat part of the keel would bump the boat.

After a few not real good launches I went back to the dealer and his mechanic looked at it and said it had not been set up properly and he lowered the back roller almost 30mm away from the keel (the amount that the keel is cut away) so that when it rolls off the first contact the back roller has is when it meets the level part of the keel so it should run level without rising 30mm.

My only concern is the back part of the boat and the motor is only supported by the two skids and not the keel roller and I looked in the Quintrex catalogue and I see their trailer has two extra skids in a "V" formation either side of the back roller I have read it helps with centering the boat but is it also there to help support the back of the boat at the transom.

I haven't had the opportunity to launch the boat with the new set up yet and I think it should go OK I am just worried about the support of the boat at the back if I should go on a bumpy road.

Does anyone else have a quintrex tinnie on a Dunbier trailer and is your set up the same as mine also does anyone know if Dunbier have those "V" skids for quintrex boats and do you think the two side skids at the back are sufficient support? Thanks in advance for any comments.

[Dirtysanchez]

But isn't the keel supported further up the rig ? I kinda understand what you are worried about.. like I say surely the keel is sitting on the centre rollers further up the vessel ?

Can you put a picture on here ?
I'd take it for a test launch / retrieve then please report back

Cheers

[foxx510]

We had a similar situation when we bought our tinny secondhand, it had never been set up right by the looks. We moved the whole boat back on the trailer so the last roller just sat under the end of the keel extrusion. This meant moving the front winch post back also, obviously. You will need to check that your balance stays right, you need around 10% of the total trailer weight on the towball, you can check this with bathroom scales. You need that rear roller to be on the keel as it supports the majority of the weight. The side skids that keep the boat upright should only have a tiny bit of weight on them, you should be able to push the boat back on the trailer easily when it's out of the water.

[sandman55]

Thanks for your reply guys yes it sits on the middle and front rollers and the nose is winched up here are some pic's that will show what I mean by the way the keel is cut away at the back which allows the boat better manoeuvrability and how the back roller is lower to line up with the keel overall.

[foxx510]

So how far back will it have to go to have the keel sit on the rear roller? The only issue may be with the front dropping down onto that cross bar as it comes back. The weight really should not be on the skids as it is now.

[sandman55]

Hi Fox the cut away section of the keel is about 600mm here are some more pic's

[foxx510]

Got a side on one so we can see how far it has to go back? It's a bit hard to tell from those angles, but it looks like it it could be too far to be practical. Would be worth sticking your scales under the towbar hitch too(use a bit of wood to hold it level and sit that on the scales) and check that what the balance is like.

[Charlie]

I have the same trailer with a stacer V Punt and the back roller is same,it's just there to guide the bow on. That boat would only weight 80 kg I don't believe it's a problem riding on the skids.
I've added two extra skids to unsuccessfully try and stop the gunnel cracking(again) and the problem is it tends to jam if the boat isn't exactly straight particularily if you back in too deep.
Stick with two preferably longer skids I'd say

[foxx510]

The problem with it riding on the skids is that it deforms the aluminium sheet against the ribs as it bounces on the trailer. The keel is the strongest point and is where they are designed to take the weight. It may not be so bad in a smaller tinny, but I wouldn't have mine riding like that. Each to their own though, of course.

[Charlie]

I generally agree but the keel extrusion doesn't go all the way back on these small boats,a bigger boat would defintely need to rest fully on the rollers.I wouldn't accept those short skids as I feel mine cracked because the front rocks too much and stesses the gunnels.Latter versions of that trailer I've seen have the longer skids.

[foxx510]

How would you go with two rollers on the rear bar either side of where that center roller is now, sitting against the strakes either side of the keel, right at the back?

[sandman55]

Got a side on one so we can see how far it has to go back? It's a bit hard to tell from those angles, but it looks like it it could be too far to be practical. Would be worth sticking your scales under the towbar hitch too(use a bit of wood to hold it level and sit that on the scales) and check that what the balance is like.
Yes it would not be practical as the cut out is 600mm I think if it isn't good enough the way it is then I should approach the dealer and try to get him to put the "V" skids on because this is the trailer that he supplied as part of the package. I don't know what it would cost and if Dunbier even make them but Quintrex make the "V" skids and Dunbier make the 4 brackets required to mount them. The launch and retrieve (I have yet to try it with the roller dropped 30mm) should be OK because the back roller is slightly further back than the hinge point of the short skids, you can see this from the pic.

[foxx510]

Yeah that's too far to move it back. Maybe being a small tinny it's not going to do too much damage riding in the skids, hard to say without knowing how heavy it is. It's not ideal though, in my opinion.

[sandman55]

I have the same trailer with a stacer V Punt and the back roller is same,it's just there to guide the bow on. That boat would only weight 80 kg I don't believe it's a problem riding on the skids.
I've added two extra skids to unsuccessfully try and stop the gunnel cracking(again) and the problem is it tends to jam if the boat isn't exactly straight particularily if you back in too deep.
Stick with two preferably longer skids I'd say
Thanks Charlie your boat sounds similar to mine. The boat weighs 78kg and the motor weighs 40kg unfortunately I have been supplied the short skids. I went into this deal pretty green knowing what I know now I would have insisted on a Quintrex trailer the Dunbier is probably a cheaper trailer cost wise so that is probably why the dealer pushed that one.

EDIT: there is also the weight of 12 litres of fuel but if I was going on a very long trip I guess I would empty the tank into the car. Did your trailer crack on the top gunnels or in the body?

[sandman55]

Yeah that's too far to move it back. Maybe being a small tinny it's not going to do too much damage riding in the skids, hard to say without knowing how heavy it is. It's not ideal though, in my opinion.
Thanks Foxx I put the weight in my last post. Its still early days yet I guess I have to try it out.

[gofishin]

…The back part of the keel on the quintrex is partially cut away which is supposed to help with manoeuvring the boat in the water…SM, yes it would help with manoeuvring ‘a little’, but the primary reason for the cutaway keel is to reduce ventilation of the prop – ventilation being the correct term here as opposed to cavitation (too often used incorrectly). By removing this part of the keel, the aerated & turbulent water flow down the ‘I’ beam keel is allowed to dissipate thus spreading & flattening it out, rather than releasing it in ‘concentrated form’ directly in front of the prop.

In the ‘good old days’ all pressed tinnies had this, now a lot don’t (time is money I guess). However, I am a little surprised at the length of the cutaway, although it has been a long time since I took much notice of small tinnies.


…he lowered the back roller almost 30mm away from the keel (the amount that the keel is cut away) so that when it rolls off the first contact the back roller has is when it meets the level part of the keel so it should run level without rising 30mm…

This is how it is generally done, and becomes more important as the size & weight of the boat goes up. However, at this end of the scale (3.55 Dart) there isn’t much scope to support the keel if this roller is not touching.


…I am just worried about the support of the boat at the back if I should go on a bumpy road... The best thing you can do for your boat is to buy:
1) a ~$30 motor support bracket, adjust it so that the motor is as low (vertical) as possible so that you don’t hit anything while trailering, and ensure the motor is in the ‘free’ and not lock position, and
2) buy a tiedown or ratchet strap, and religiously use together with 1), however, don't over tighten.

The cause of most damage to small tinnies is while trailering, especially with the motor up on the ‘lock’ bracket bouncing all over the place as they do (if you can trail with the motor vertical, and maintain sufficient ground clearance, do so, and you don’t need a bracket – but still use a ratchet strap)


… those "V" skids for quintrex boats and do you think the two side skids at the back are sufficient support? Thanks in advance for any comments. If you are talking about the transverse (across-ways) guide skids that guide the keel onto the roller, they are a common product sold at most marine outlets. They would help stop the keel popping off the back roller while retrieving, especially when you are ‘learning the ropes’.

As for the side skids - yours a pretty much par for this size of rig. Adjust your winch post (move the boat) so that the first bottom rib (closest to the transom) is fairly close to being directly over the centre of the skid, without having more than say 100mm of transom overhang. If needed (probably not), adjust the axle so that there is sufficient down weight on the tow ball. Bit hard to tell from your photos, but it seems pretty close to ideal as it is.

Personally, I would raise the rear roller back up to support the keel, but I would also smooth out the hump/transition in the keel cutaway (remove motor, put tinny on its side & grind/file away) so that it doesn’t get caught or bump up too much over the roller. The side skids should then prevent the tinny from rocking, and not support the hull weight as such – best thing for a tinny. Also, don’t use it as a box trailer when going camping etc, as this kills a tinny quickly too.
Cheers
Brendon
PS. Not meaning to be offensive in any way, but when you get the hang of things a bit more it will all seem very easy, and you will have a chuckle about the trouble you ‘used to have’.

[sandman55]

Thanks gofishin I got a lot of info out of that post.

The best thing you can do for your boat is to buy:
1) a ~$30 motor support bracket, adjust it so that the motor is as low (vertical) as possible so that you don’t hit anything while trailering, and ensure the motor is in the ‘free’ and not lock position, and
2) buy a tiedown or ratchet strap, and religiously use together with 1), however, don't over tighten.

The cause of most damage to small tinnies is while trailering, especially with the motor up on the ‘lock’ bracket bouncing all over the place as they do (if you can trail with the motor vertical, and maintain sufficient ground clearance, do so, and you don’t need a bracket – but still use a ratchet strap)

The trailer has plenty of ground clearance even when I drive out my drive way (also with my set up at home I don't need to back it though it is pretty easy to back) so the motor is pretty vertical I am supporting the motor with a rubber okka strap the dealer warned me to use that not to use a rope because people over tighten it. I hook the okka strap from the trailer round the leg and back to the other side of the trailer.


If you are talking about the transverse (across-ways) guide skids that guide the keel onto the roller, they are a common product sold at most marine outlets. They would help stop the keel popping off the back roller while retrieving, especially when you are ‘learning the ropes’.

As for the side skids - yours a pretty much par for this size of rig. Adjust your winch post (move the boat) so that the first bottom rib (closest to the transom) is fairly close to being directly over the centre of the skid, without having more than say 100mm of transom overhang. If needed (probably not), adjust the axle so that there is sufficient down weight on the tow ball. Bit hard to tell from your photos, but it seems pretty close to ideal as it is.

So far I haven't had any trouble retrieving just launching and I am getting better and later when the shine has worn off I will make a stainless steel bracket to adjust the front roller up (which is fixed) so that I can make the back roller as low as possible (2 to 3 inches) because I have 13 inch wheels also I fitted bearing buddies so I can put it in close to the axle.

I cant move the boat winch post as you suggested because I wouldn't be on the front roller but I just checked and the side skids span from the transom to the first rib so I guess both ends are on something solid.

The trailer axle is fixed but the down weight on the tow ball I think is sufficient if I could I would make it a little lighter but its not too bad.


Personally, I would raise the rear roller back up to support the keel, but I would also smooth out the hump/transition in the keel cutaway (remove motor, put tinny on its side & grind/file away) so that it doesn’t get caught or bump up too much over the roller. The side skids should then prevent the tinny from rocking, and not support the hull weight as such – best thing for a tinny. Also, don’t use it as a box trailer when going camping etc, as this kills a tinny quickly too.
Cheers
Brendon
PS. Not meaning to be offensive in any way, but when you get the hang of things a bit more it will all seem very easy, and you will have a chuckle about the trouble you ‘used to have’.

I almost got to the tinny with the grinder as I thought this was my only option but I got cold feet and saw the dealer which was good because I got a second hard blue plastic roller out of him now the only rubber one is at the front and that is ok. I will give the setup with the roller lowered a try and see how it goes and if I am not happy I will do as you suggest. Thanks for the advice on not using it as a trailer for camping because this was what I had in mind I will have to use the station waggon ;D Thanks again for your advice I feel a bit more reassured now.

[MyEscape]

Well I've got a Sejay 5.35 which weighs about 280kilos plus a 40hp Yamaha onthe back. The cutout on my keel is not as long as on your Quintrex, though I don't think that's the problem.

My back roller is also not touching. Further the whole weight of the boat seems to be sitting on one roller.

I think as long as the skids are just touching, or touching enough so the hull doesn't rock sideways when its on the trailer then it should be fine,and launch ok

Steve

[sandman55]

Thanks Steve my boat is way lighter than yours so if your is OK then mine should be too. I hope to try it out in the next day or two depending on the weather.

[Spaniard_King]

I would put single post wobble roller on each side of the keel at the rear. this will support the baot either side of the keel and allow the keel to pass between the rollers centering the boat as well

[sandman55]

Thanks Garry foxx510 suggested some thing similar. I have been thinking if I could put some sort of a packer between the back roller and the keel and take it off before launching. Some thing for me to think about then sell to Quintrex ;D in the mean time I will try this setup but will keep thinking about it. I have a picture in my mind of another roller or small slide that I could use an over centre locking set up that I would pop up against the keel for travelling and pop down for launching http://www.cheesebuerger.de/images/smilie/konfus/c010.gif some thing to think about.

[CHAPPY]

My 385 explorer had the same problem so I replaced the 2 rear outside skids with 2 large double pivoting rollers. The boat now guides on well with the lowered centre roller and is well supported on 4 places by the pivot rolers. I have also put a hacksaw mark on the lower central roller and we lift it up to support the keel if we are towing any great distance. For short hauls say 10 k at slow speed on good roads no problem. It has been set up this way for 4 years with no cracks. I also moved the boat forward so the pivot rollers are within 50mm of the transom . Chappy

[sandman55]

Thanks for that Chappy that is a good Idea for long hauls I'm still thinking about some sort of packer or a keel support that I can easily move up or down.

[sandman55]

Here is the proto type of the packer idea. I will only use this on long distances or bumpy roads. I will have to get some hard wood for the finished one I got my router and made a groove for the keel though flat would be OK.
I had to thread the rope through the side of the block as it got in the way of the roller for inserting the block when the holes were vertical. I will have to file a wee bit off the groove to put more weight on the side slides as the boat is rocking a tiny bit.

[geoffmck]

Foxx510 and Spaniard King have come up with the eaisest and best solution. That's waht I would be doing.
(PS I should have thought of that when I had a Stacer 420 on the same trailer setup! I just raised the keel roller up but it did then make launching/retrieving more difficult as you have mentioned)

[gofishin]

That's not a bad idea sandman - gives you the best of both worlds. Importantly, it keeps the stress point on the keel, where it should be.

Gary, wobble rollers give very high concentrated load points, and are a no-no on pressed tinnies up to & incl 3mm bottom (and i have seen more than enough damage caused by them to know this is fact). As a guide-on they would be OK, but should not support the 1.6mm bottom sheets while up on the trailer.
cheers

[Poseidon]

This has been a great read and answered the same questions that I had. My boat sits on a Dunbier Centerline trailer and has the same issue with the cut back keel. I wasn't able to get the boat easily off the trailer with the rear roller hard against the keel given the difference in keel heights so just keep the rear roller the same height as the others to eventually take the weight when dropping the boat at the ramp. Having seen the photo this morning of the block of wood option from Sandman I got the saw and chisel out and gave it a go. It will work fine and take some weight from the transom area away from the rollers further away. I had another issue that this block should also help me with and that was arriving home with the boat a little off centre from when it was at the ramp. As the rear roller wasn't in contact with the keel it allowed the transom area to move slightly off centre and with a lever effect move the keel further forward on the rollers off centre as well. No big deal however the groove in the timber should keep the rear keel centered on the rear roller and hopefully alleviate this.
Anyway, here a few photos of the block. The rubber strap holds the block around the roller and the yellow rope allows you to pull the block off easily before backing down the ramp.

Thanks Sandman for your photo as I have been scratching my head for ages tying to work out a solution.

Regards Cameron.

[sandman55]

Thanks guys and Cameron you have improved on the idea, I like the handle and I could use an okka strap for the rubber. I will have to get a bit of hard wood for a better one.

[foxx510]

A chunk of nylon or poly plastic(ie chopping board plastic) would be the go if you are going that way, as it won't compress like timber will on bumpy roads as the boat pounds on it. You might get away with a really good piece of hardwood.

[sandman55]

A chunk of nylon or poly plastic(ie chopping board plastic) would be the go if you are going that way, as it won't compress like timber will on bumpy roads as the boat pounds on it. You might get away with a really good piece of hardwood.
Yes that would be good but a piece of hard wood would be easier to come by.