what sort of speed

slate1234 · 03 March 2014, 20:36

Hi all I have got myself a 9.8hp 2st tohatsu, I will be useing this on a 3.2m sunsport sib and was woundering what sort of speed will I get with two bloke's around the 170kg mark (combined weight) and 22lt fule tank and light fishing tackle
Thanks

willk · 03 March 2014, 20:50

6kts or 16kts - depending if it planes or not

slate1234 · 03 March 2014, 20:55

Maybe I should of asked will it get on the plane then

AJ. · 03 March 2014, 20:56

I've got the 2.9 sun sport. Think I got 17 knts out of mine. Tad slower with two and if it's anything like mine passenger will have to lean over the bow to get it over the hump.

PeterM will remember the speed but he is no longer reading Ribnet apparently! LOL

AJ. · 03 March 2014, 20:57

Quote:

Originally Posted by slate1234

Maybe I should of asked will it get on the plane then

Yours should be easier than mine as its longer

slate1234 · 03 March 2014, 21:29

Thanks AJ, I have waited to get the right engine for a while and hope I haven't made a mistake

AJ. · 03 March 2014, 21:31

Quote:

Originally Posted by slate1234

Thanks AJ, I have waited to get the right engine for a while and hope I haven't made a mistake

We'll sort after engine worth the wait

Locozodiac · 04 March 2014, 00:55

Slate,

Move your boating mate further bow, hope not as a bow mask. inflate sib and keel to at least 3.0 psi with gauge, trim engine to be perpendicular to water level, once engine is warm give it a full wot, see if planes, fingers crossed. If not, probably will need to install trim tabs to make that combo plane faster with a less HP engine than rated for.

A less HP engine will plane faster a larger sib/rib, more surface to slide better + less hull drag to overcome fast.

Happy Boating

slate1234 · 04 March 2014, 17:21

Thank's for the reply's I am picking up the engine next week so fingers crossed all will be ok

frankc · 07 March 2014, 15:33

We run an Avon 3.1 Rover plywood floor with a Nissan 9.8, and it performs very well with two people. We ran with a 15 HP in the past which was unpleasant at full speed.

I cannot imagine not planing with a 3.2 unless it is a much heavier boat.

Incidentally, the boat is rated for up to 10 HP.

slate1234 · 07 March 2014, 18:13

Thank's frankc, it's a 3.2m air floor so should be lighter in weight,
slate

frankc · 07 March 2014, 19:26

We also run the 9.8 on a Zodiac 285 Acti-V, so horsepower is no problem at all on that air floor. We would not run the Zodiac at speed with one aboard. Your longer hull should plane like a dream.

You will like that motor very much. If ever a motor was designed for portable inflatable boat use, this is the one.

SIBer · 08 March 2014, 21:02

Thats a big fuel tank I use a 12 litre but depends how far you want to go. At WOT you will butn 4 litres an hour.
I have a similar set up and as above, shift weight to get up on the plane and if flat clam expect 20 mph.
Make sure your boat is well inflated and enjoy.

NWC100 · 09 March 2014, 09:32

I use a 9.9 and a 22 litre tank, it's a pretty good combo I think for my 3.4 m zodiac, the tank gives some extra weight up front and also I often run at wot against tide so empties pretty quickly (and engine needs service and New prop

I've done about 35 miles from one tank plus both my back up bottles so 25 Ltrs total I was down to fumes though after!

Nick

lightning · 15 March 2014, 09:10

I've got a Tohatsu 9.8 on my Zodiac 2.85m SIB and with this engine the boat goes like a rocket, easily exceeding the maximum design speed of the hull.

This boat has a solid floor, but with inflatable V keel.

With two of us on board it will do 20mph. The boat is rated to 17mph according to the plate on the trsnsom. Above this speed it becomes harder to steer, as it wants to go in a straight line.

However this means that at lower speeds say 15mph the engine is more refined and quieter, as it is not absolutely flat out (like my Mariner 6hp was at that speed)

HUMBER P4VWL · 15 March 2014, 10:00

I wonder what my 2.4m grp hulled rib would do with one on the back?

rated to 4hp but reckon it'd be ok. Wheeeeeee!

slate1234 · 15 March 2014, 14:33

Thanks for the replies,I have picked up the outboard and it is very light ticks over lovely and sound's very nice , I was going to launch this morning but it way to windy here, I also have to finish running the engine in, I was hopeing to have a run from Abergele to Llandudno never mind allways next week