Took me Sib for a Spin :)

henryfreston · 10 March 2013, 18:43

Saturday was my first opportunity to use my newish sib. I took it out once before in September, but i did not have a proper go on it. I have to say I am very, very impressed!

She is a 4m ali deck honwave with a 2006 25hp 2 stroke engine. When they had been bought in september, they had done 30hrs. The set up came with everything as well as a road trailer. All is immaculate condition with a full service history. How much would you have expected to pay for this? (just curious because i think i got an awesome deal). It was a step up from my 2.6 meter sib with a 4hp 4 stroke.

Anyway, I took her out on the gower, Oxwich bay. There as a decent sell and some chop, but nothing that would put me off. The weather as excellent for the time. Mostly sunny and medium winds. I as SUPPOSED to be fishing with my friend with a 3.2 meter airdeck honave with a 5hp honda, but i ended up doing endless circuits of the bay at WOT!

I have a couple of questions though. Firstly, when i do turns at high speed i get a little cavitation (the boat is fine and it does not bother me much as it is only a little bit) I just wanted to know if I could solve it because it would be better without it, or do I just have to put up with it? Also, I found recovering the boat on the slip way a bit of a nightmare. The deck got completely flooded making it difficult to lift onto the trailer. I know SIBs are supposed to be used with skids, but would rollers be OK? My friend has rollers and he assures me it is a lot easier even with a SIB.

But looking back it was a great day out! Caught a few pouting even with a easterly wind! Bring on the summer with my new knee board! Also, just being cheeky here, but how fast would you expect this boat to go? (I know this is the ultimate newb question, but atm i have no way of recording speed.)

Thanks for reading,

Henry

matt h · 10 March 2013, 18:53

Quote:

I have a couple of questions though. Firstly, when i do turns at high speed i get a little cavitation (the boat is fine and it does not bother me much as it is only a little bit) I just wanted to know if I could solve it because it would be better without it, or do I just have to put up with it? Also, I found recovering the boat on the slip way a bit of a nightmare. The deck got completely flooded making it difficult to lift onto the trailer. I know SIBs are supposed to be used with skids, but would rollers be OK? My friend has rollers and he assures me it is a lot easier even with a SIB.

Cavitation could be caused by engine too high or trimmed up too much, basically prop coming out of the water so lower that spinning egg whisk.

y u lifting on to trailer/ submurge the trailer so it floats on or get launchin wheels. wheel barrow sized wheels as they go over pebbles etc.

if its full of water upon recovery. take it for another run with drain plugs out and lose the water first before recovery

henryfreston · 10 March 2013, 18:56

Quote:

Originally Posted by matt h

Cavitation could be caused by engine too high or trimmed up too much, basically prop coming out of the water so lower that spinning egg whisk.

y u lifting on to trailer/ submurge the trailer so it floats on or get launchin wheels. wheel barrow sized wheels as they go over pebbles etc.

if its full of water upon recovery. take it for another run with drain plugs out and lose the water first before recovery

I know about pulling the drain plugs, but the rubber seal fell out of the drain plug, so as soon as you stop water pours in.

matt h · 10 March 2013, 18:57

well get that sorted and thats one problem solved

ref the cavitation, is the high pressure air floor up to its required high pressure?

henryfreston · 10 March 2013, 19:04

Quote:

Originally Posted by matt h

well get that sorted and thats one problem solved

ref the cavitation, is the high pressure air floor up to its required high pressure?

it is an ali floor, with a inflatable tube keel. It says to inflate it to 0.35 BAR, i did with a BRAVO pump, so yes, I know it is the right pressure.

What launching wheels to you recommend. The ones I boat for my last SIB were rubbish and cost me 60 big ones. I would need a good, high, sturdy pair.

CHeers for help

matt h · 10 March 2013, 19:05

Just look on flea bay, i think they are about 180 but work well, made by Trem i think, shaped like a banana as you have a inflatable plning pad so have to clear that unless its a older honwave with a straight down transom. these are the ones with plastic wheelbarrow tyres, ideal for shingle slips and sand

Poly · 10 March 2013, 19:36

Quote:

Originally Posted by henryfreston

... a 2006 25hp 2 stroke engine...but i ended up doing endless circuits of the bay at WOT!...... when i do turns at high speed i get a little cavitation (the boat is fine and it does not bother me much as it is only a little bit) I just wanted to know if I could solve it because it would be better without it, or do I just have to put up with it?

Quote:

Originally Posted by matt h

Cavitation could be caused by engine too high or trimmed up too much, basically prop coming out of the water so lower that spinning egg whisk.

I am guessing that this engine has no power trim? In which case the trim angle is a compromise for best overall behaviour. You can lower the trim, but it may be slower, wetter, less comfortable the rest of the time as a result. If you had a bigger boat/engine with power trim you would trim down for tight turns. You may adjust the trim for each trip to suit the conditions / load etc - but probaby you'll find one setting which suits 80% of occasions, [Technically this will be ventilation rather than cavitation].

Quote:

Also, just being cheeky here, but how fast would you expect this boat to go? (I know this is the ultimate newb question, but atm i have no way of recording speed.)

20 knots-ish. Might get 24 lightly loaded on a flat calm day.

Quote:

y u lifting on to trailer/ submurge the trailer so it floats on or get launchin wheels. wheel barrow sized wheels as they go over pebbles etc.

Matt is right - the technique is slightly different for a bunked trailer from rollers - generally that means putting the trailer in deeper rather than driving it on. your friend is probably right that life is a little easier with rollers - BUT I wouldn't keep a sib on a typical small roller coaster long term as the load is not as evenly distributed.

thestig1973 · 10 March 2013, 19:42

Quote:

Originally Posted by henryfreston

Saturday was my first opportunity to use my newish sib. I took it out once before in September, but i did not have a proper go on it. I have to say I am very, very impressed!

She is a 4m ali deck honwave with a 2006 25hp 2 stroke engine. When they had been bought in september, they had done 30hrs. The set up came with everything as well as a road trailer. All is immaculate condition with a full service history. How much would you have expected to pay for this? (just curious because i think i got an awesome deal). It was a step up from my 2.6 meter sib with a 4hp 4 stroke.

Anyway, I took her out on the gower, Oxwich bay. There as a decent sell and some chop, but nothing that would put me off. The weather as excellent for the time. Mostly sunny and medium winds. I as SUPPOSED to be fishing with my friend with a 3.2 meter airdeck honave with a 5hp honda, but i ended up doing endless circuits of the bay at WOT!

I have a couple of questions though. Firstly, when i do turns at high speed i get a little cavitation (the boat is fine and it does not bother me much as it is only a little bit) I just wanted to know if I could solve it because it would be better without it, or do I just have to put up with it? Also, I found recovering the boat on the slip way a bit of a nightmare. The deck got completely flooded making it difficult to lift onto the trailer. I know SIBs are supposed to be used with skids, but would rollers be OK? My friend has rollers and he assures me it is a lot easier even with a SIB.

But looking back it was a great day out! Caught a few pouting even with a easterly wind! Bring on the summer with my new knee board! Also, just being cheeky here, but how fast would you expect this boat to go? (I know this is the ultimate newb question, but atm i have no way of recording speed.)

Thanks for reading,

Henry

Top speed?
25hp 2 stroke yamaha on my futura recorded 31mph on GPS last Monday, although it was an I phone app I used to measure speed so possibly not 100% accurate

Similar size sib/horsepower so I suspect similar top end

TRevor Lawson · 10 March 2013, 21:08

Used to have a t 40 , with ali floor, mine used to behave same as yours on tight turns a lot depended on sea conditions and load but never realy cured the prop slip, re recovering with a bunked trailer,used to put trailer right in and float boat over bunks, easy, to help i fitted a winch on trailer , connected to tow bar and unhooked trailer and used to launch/recover trailer back to car further up slip, got it off to a fine art.

henryfreston · 10 March 2013, 21:10

Quote:

Originally Posted by TRevor Lawson

Used to have a t 40 , with ali floor, mine used to behave same as yours on tight turns a lot depended on sea conditions and load but never realy cured the prop slip, re recovering with a bunked trailer,used to put trailer right in and float boat over bunks, easy, to help i fitted a winch on trailer , connected to tow bar and unhooked trailer and used to launch/recover trailer back to car further up slip, got it off to a fine art.

Good idea with unhitching the trailer. One day i may leave the sib and go for a 3.5m rib instead, what are your thoughts?

TRevor Lawson · 10 March 2013, 21:50

As you can see i now have a 4.5mtr rib it gives a much better ride than the sib making it more usable in all conditions, would like a bigger one but storage, cost to run, etc all play their part in what toys we have, minus points now have to launch on proper slip, used to be able to beach launch with launch wheels, was usually free now have to pay but was a great sib and had many fun days out in it even going to iow with the rib net boys.

Festinghouse · 11 March 2013, 05:18

cavitation (or ventilation) is a common problem on these, partly due i think because of the flexing of the transom with the movement of the tubes affecting the trim angle. you will learn to play the throttle in corners to avoid it. my old yam 360s with 25merc did 26mph on the gps. friend of mine has a 4m honwave with a yamaha30 and gets about the same speed.

Locozodiac · 11 March 2013, 16:37

Henry,

Is that a Merc 2, 4 stokes you currently have on transom? What's the distance from lower to upper transon at keel level in centimeters. With trim angle set to have engine paralell to water level once sib is floating and well inflated to it's working pressure, you shouldn't have aireation, ventilation at close turns, propably engine is sitting a tad higher that is shouls be. Are there water splashes over transom at speed ?

Happy Boating

henryfreston · 11 March 2013, 17:42

Quote:

Originally Posted by Locozodiac

Henry,

Is that a Merc 2, 4 stokes you currently have on transom? What's the distance from lower to upper transon at keel level in centimeters. With trim angle set to have engine paralell to water level once sib is floating and well inflated to it's working pressure, you shouldn't have aireation, ventilation at close turns, propably engine is sitting a tad higher that is shouls be. Are there water splashes over transom at speed ?

Happy Boating

I don't quite understand 'Is that a Merc 2, 4 stokes you currently have on transom?' And no, no splashes. It is not at close turns, weirdly, it is at, well, average turns. I either have to do a really tight turn or take it right round on a slow turn. It is therebetween I struggle! Also if I power up during the turn. The boat is currently at my caravan on the gower so i cannot access it. It think it is the trim being set wrongly. I think it needs to be trimmed down a bit more. I will try it on friday with the trim set differently. Cheers

Locozodiac · 11 March 2013, 21:46

So you have a 4 mtr Honwave alum floor sib, right ? Was asking if it was a Mercury brand engine, or it's any other brand one ? When you replace the missing water drain diaphragm for a new one, once well setaed inside valve assembly , squeeze some silicone direct from tube to the protruding inside stem to increase it's diameter, that way won't be wiped out nor lost again when water exits from deck while sib it's on plane.

Happy Boating

henryfreston · 11 March 2013, 21:49

Quote:

Originally Posted by Locozodiac

So you have a Honwave alum floor sib, right ? Was asking if it was a Mercury brand engine, or it's any other brand one ? When you replace the missing water drain diaphragm for a new one, once well setaed inside plug, squeeze some silicone direct from tube to the protruding stem to form a thicker stem, that way won't be lost again when water exits from deck while sib it's at plane.

Happy Boating

cheers for the tip

and it is a 25hp 2 stroke tohatsu (the aquamarine blue and red one)

keeno07 · 14 March 2013, 21:11

Think a bit of practice is needed with launch & recovery. You should never lift the boat as you could do yourself a serious injury. Take on board the advice you have been given & yes, trailer needs to be submerged under the sib before recovery using the options mentioned. Bunkered trailers are best for sibs as they spread the load of boat/trailer. Rollers concentrate load at certain point, not good! Also rollers may well damage the fabric of the boat!

Exe treme · 16 March 2013, 13:39

Hi Henry
Just a couple of thoughts... Does cavitation only occur when turning to the side you are sitting? If so, it could just be the angle of the transom with the weight to one side. Another consideration could be that Honwave alu floors have a fairly flat vee at the stern and tend to slide a bit until the tubes hit the water. This could explain why you notice cavitation in medium turns, but not so much in tighter turns. Also, if you have a gps-enabled smartphone, you can get a speed reading from that.
PS. Love the Gower, what a great place to start your sibbing experience. Perhaps a trip round to Worms Head would be a good summer trip for you?

henryfreston · 16 March 2013, 13:49

Quote:

Originally Posted by Exe treme

Hi Henry
Just a couple of thoughts... Does cavitation only occur when turning to the side you are sitting? If so, it could just be the angle of the transom with the weight to one side. Another consideration could be that Honwave alu floors have a fairly flat vee at the stern and tend to slide a bit until the tubes hit the water. This could explain why you notice cavitation in medium turns, but not so much in tighter turns. Also, if you have a gps-enabled smartphone, you can get a speed reading from that.
PS. Love the Gower, what a great place to start your sibbing experience. Perhaps a trip round to Worms Head would be a good summer trip for you?

thanks for you input. Yes the Gower is lovely. Already had a few good moments. I really am already considering moving to a 3.5m rib though. Not too sure yet though. I am just a bit annoyed at a few things such as; water, sand and algae build up in the hull and the flooring which slows the boat down loads. I had to spend about 45 mins with my face down sponging out water! I just feel it will be a lot easier with a rib- you can use rollers to just roll the rib in to the water, deeper hull with less cavitation etc etc. What do you think guys? I am sure many of you have considered the same decision.

Exe treme · 16 March 2013, 15:17

If you have space (and trailer) for a solid-hulled rib, there are fewer compromises and no worries about getting the floor pressure right. You might also find the range of lightweight aluminium hulled ribs (not alu floor sib) of interest. I know the Xpro and Highfield brands offer a good selection at good prices. You can view them both at:
www.seaswift.co.uk