Modifications to valiant DR 490

[two stroke mick]

After reading the last issue of Rib International and the modifications to the SR4. I modified the seat top on my own rib. Outhills carried out the work an basically the cusion is now 230mm thick instead of 90mm. This has substantially reduced the punishment that your back takes.

I also looked at the deck system in that issue of RI but those usits are too expensive. I did get 4 rubber mats made by Varian. These mats are approximatly 17mm thick and have holes in them. It is surprising how much these mats reduce the vibration into the lengs on a heavy landing.

Yesteday I did a 76 nm round trip from westport to killary harbour (West Coat of Ireland) . The differance in comfort in using the rib is very noticable. I was running with a 21" prop but the engine struggled with this prop I think I will return to the 19"

TSM

[davis]

Hi I too have a valiant 490 and was thinking of moving the jockey seat forward about 18 inches to have more space at the rear. I asked about this before but nobody had any replies, what do you think of this idea, would it affect the performance of the boat, on the powerboat course we were told to move everyone forward to get the boat on a plane , so having more weight forward must be an advantage, anyone any thoughts on this?

[9D280]

Davis,

On the course, did you then all move back after it started planing? - there's plenty of threads in the SIB section about that.....

For what it's worth my old SR4 had 2 30L fuel tanks, the front tank had a hose to the engine so I didnlt need to lug a 30 KG lump across the boat at an inaoppropriate moment. I found that if I emptied the rear tank first, as you say, time to plane was reduced (slightly), but if I emptied the front first, the helm became lighter, and the top speed improved by about half a knot..... but it took forever to get on the plane! I eneded up deciding on which tank to empty first by what I was doing with it at the time. I had a fixed trim 25 on the transom, no idea what you are shoving your Valiant along with, but the effects I saw can be accounted for in real time with a PT on the engine.

If you open the rear up for more space, is it for stowing more stuff? If so you are likely to alter performace more by loading the boat than moving you forward 18" on a loaded boat. If however you are single handed or you+ crew on a dingy club rescue boat and need the space for that then moving the the engine trim pin (or your trim switch if it's PT) will probably negate any effecs of moving the console on a light setup with a singl tank of fuel.

If you want to experiment, a couple of sand bags or a portable tankat the bow will proably give you a similar performance effect.

[nord]

Hi, i am thinking of gething a new Valiant DR 490 and 60 hp mercury.
How is this performing compare to a DR 450 and 50 hp?

[two stroke mick]

Hi Nord

I have a DR 490. I am quite happy with it now that I have carried out some modifications

Installed a 3" trunk

Increased the depth of foam in the seat

I think for the price of a new DR 490 that you could pick up a larger better rib for similar money. That said Mr DR 490 is easy to launcy and recover. It is light on petrol and any car can pull it. I use mine on the west coast of ireland and am fairly happy with it.

TSM

[Steve_B]

Before you start to move anything on the deck of a Valiant, check with your dealer, as they often bond the consul and jockeys to the floor, then add fasteners.

I was told that there is a danger in damaging the deck if you try to adjust ant of the above.

Regards