SIB performance

Leapy · 16 January 2010, 09:26

Bought a Seago 290R (air floor, inflatable keel) last year together with a Suzuki DF5 outboard. We've only managed to use it once so far (too much time on the RIB

) but based on that one trip I'm wondering if I'm over-expecting from it.

The book of words with the boat (subsequently confirmed by email from Seago) says all chambers should be inflated to 2.5psi, which we did. This seems fine for the tubes but from reading around seems low to very low for the air floor and inflable keel (some guy on here recently is talking about inflating his floor to 12psi).

This months MBM has a group test of 14 SIBs in the 2.5/2.6m range - none of them Seago

- across a very wide price range (£350 to £1350)

The words of wisdom from the test is that the performance of a SIB most probably is a function of the hull design...flat floor: poor planing, doesn't turn well, but light and small when packed; slatted floor: slightly better planing, still poor in turns; air floor with inflatable keel/V bottom: planes easiest, good in turns but heavier/bulkier.

When it comes to performance absolutely flat out two up with our Seago 290 we saw 8mph best and not a chance of planing. The best performer of the MBM group did 15mph two up on the same 5hp we have. Some of the test boats managed 6mph on 2.5hp.

Any views/thoughts/comments from owners of similarly sized and powered SIBs?

lightning · 16 January 2010, 10:41

I've got a 2.6m Zodiac SIB (wooden floor but with inflatable V keel) and the engine is a Mercury 6hp.
On a lake it will do about 14.5 mph according to the GPS, with two of us on board. It gets on the plane easily, taking under 5 seconds from opening the throttle.

thornbackflound · 16 January 2010, 11:07

Never checked me speed i have a 2.70 seago and a 3.3 outboard,on a flat day when you get them?lol, im sure i get more then 8mph , not much over ?wooden floor ,heavy anti slip mat and 2 of us ,2.9 longer so heavier how heavy are the people on board? and 5hp can all have effect on how the sib performs

C-NUMB · 16 January 2010, 12:52

Have a old BRIG 300, very similar in size and weight(but wood floor, inflatable keel) together with a Tohatsu 3,5HP 2stroke. With me alone it planes nicely, WOT guessing close to 10 knots. Taking one light kid along, still on plane, but with two adults no chance to plane.

Guess the weight of the engine, gear and crew is pretty critical on such boat/engine size. How is it performing with only one on board?

cyberstoker · 16 January 2010, 15:05

Quicksilver 2.5 with inflatable floor and keel and 4hp gets up to about 5 knots.

Locozodiac · 16 January 2010, 15:47

Seago's are pvc 0.9 mm fabric made, so can hold 3.0/3.5 psi once on water with no problem at all including keel, air mat floors must have at least 10 psi for the floor to rock the least. Used to inflate my old 320 air mat floor sib to 12/14 psi (1 Bar)to perform near perfect. Air mats are no ballons, have thousand of crissed/crossed threads inside, can hold high pressure. A well inflated sib will perform much nicer, plane faster and handle load better.

Happy Sibbing

Leapy · 16 January 2010, 16:17

Quote:

Originally Posted by Locozodiac

Seago's are pvc 0.9 mm fabric made, so can hold 3.0/3.5 psi once on water with no problem at all including keel, air mat floors must have at least 10 psi for the floor to rock the least. Used to inflate my old 320 air mat floor sib to 12/14 psi (1 Bar)to perform near perfect. Air mats are no ballons, have thousand of crissed/crossed threads inside, can hold high pressure. A well inflated sib will perform much nicer, plane faster and handle load better.

Happy Sibbing

That's interesting...it goes against the handbook and against the email from Seago but seems to be in line with what others have told me.

I'll give it a go next time...if you hear a loud bang

you'll know what it was

Leapy · 16 January 2010, 16:20

Quote:

Originally Posted by C-NUMB

Guess the weight of the engine, gear and crew is pretty critical on such boat/engine size. How is it performing with only one on board?

Haven't tried one-up. Another of those next-time-things-to-do.

The engine weighs 19kg...the other half and I about 160kg together.

Hmmm. The boat weighs 30kg or so...engine 19kg...crew 160kg. I wonder where the problem is

lightning · 16 January 2010, 18:26

Where are you testing your boat? I found that ours would not exceed about 5.5mph on the canal (not that you'd want to), it just produced a large following wave and the bow came up. This led me to believe there was something amiss with the trim etc.
However, we took it on some open water and it shot up to 14mph+ two up with no trouble at all.

Leapy · 16 January 2010, 19:29

Quote:

Originally Posted by lightning

Where are you testing your boat?

On the Fal Estuary...a touch wider and deeper than a canal

I think it down to weight, modest power and me expecting too much

Locozodiac · 17 January 2010, 00:42

Quote:

Originally Posted by Leapy

That's interesting...it goes against the handbook and against the email from Seago but seems to be in line with what others have told me.

I'll give it a go next time...if you hear a loud bang

you'll know what it was

Don't worry will not explode, will fly away, maybe a precaution issue specially boating in extreme heat environments, try at least 3.0 psi, will perform much better.

Happy Sibbing

nice.diver · 05 February 2010, 02:08

mark III GR
40hp johnson
2 people
24 mph on the gps

willfinch36 · 05 February 2010, 11:53

When I was younger (im now 20 - feel old!) In an AVON Redstart with a 4hp Johnson I did 13knots! not bad....

Leapy · 05 February 2010, 12:08

Quote:

Originally Posted by willfinch36

im now 20 - feel old!

Brace yourself for the future

phillnjack · 29 May 2010, 16:41

When I was younger (im now 20 - feel old!) In an AVON Redstart with a 4hp Johnson I did 13knots! not bad....

Dream on, i had the same boat and engine 8 mph max.
but with c craft and inflatable keel the engine would easily do 12mph.

the redstart had the outboard bracket and no inflatable keel, no points on the back and
realy made as a rowing tender.
No way on earth to get a redstart to plane without adding a inflatable keel.

13 knots in a restart ha ha ha ha ha

phill

willfinch36 · 29 May 2010, 16:42

Quote:

Originally Posted by phillnjack

When I was younger (im now 20 - feel old!) In an AVON Redstart with a 4hp Johnson I did 13knots! not bad....

Dream on, i had the same boat and engine 8 mph max.
but with c craft and inflatable keel the engine would easily do 12mph.

the redstart had the outboard bracket and no inflatable keel, no points on the back and
realy made as a rowing tender.
No way on earth to get a redstart to plane without adding a inflatable keel.

13 knots in a restart ha ha ha ha ha

phill

How heavy are you.........
Yup sounds hard to believe...... GPS verified....

Question · 29 May 2010, 20:53

3.10 meters airdeck, Yam. 8 hp

44kg boat, 27kg, motor, 10kgish oil, 3kg anchor, approx. 150 kg crew (two persons)

Yesterday, GPS recorded 28 km max (help of the wind maybe

), I think it's near 15 knots? It planes well with this weight, but not with one more person.

PS: This is despite... I couldn't inflate the floor with the default pump well, so it takes a kind of ^ shape (like 170 degrees) in water, and motor is in break-in period. But actually I'm not after speed at all. If it doesn't sink with 4 persons and runs smooth in nice weather that's a good performance for me

Q

phillnjack · 31 May 2010, 19:38

You will not get great speed from a redsstart even with 100hp.

soft floor, no inflatable keel, round transom, etc

the redstarts and redcrests were not made to plane, and they didnt.
they were designed as rowing tenders, nothing more nothing less.

i do know that mnany people get good speeds from small inflatables, but they are
boats with inflatable keels or wooden keels.
Points on the transom and boats that are made to plane.

the redstart was NEVER MADE TO PLANE and just dont.

ive had 2 of them both with outboards on the transom brackets and both would not plane.

now unless tyhis boat has been modified it will not plane.

13 knots = around 15mph and that equals 24 kilometers per hour.

this would be well on the plane for such a small boat,

something tells me that the 13knots should be 13 kilometers per hour ?
that would be just about right for a redstart or redcrest

phill

Nos4r2 · 31 May 2010, 23:30

Years ago I had one planing with a Seagull 40+.

It took me lying on the floor to use myself as a keel to do it though...

Saying that, the new versions can have an inflatable floor so anything is possible.

willfinch36 · 01 June 2010, 09:27

Quote:

Originally Posted by phillnjack

You will not get great speed from a redsstart even with 100hp.

soft floor, no inflatable keel, round transom, etc

the redstarts and redcrests were not made to plane, and they didnt.
they were designed as rowing tenders, nothing more nothing less.

i do know that mnany people get good speeds from small inflatables, but they are
boats with inflatable keels or wooden keels.
Points on the transom and boats that are made to plane.

the redstart was NEVER MADE TO PLANE and just dont.

ive had 2 of them both with outboards on the transom brackets and both would not plane.

now unless tyhis boat has been modified it will not plane.

13 knots = around 15mph and that equals 24 kilometers per hour.

this would be well on the plane for such a small boat,

something tells me that the 13knots should be 13 kilometers per hour ?
that would be just about right for a redstart or redcrest

phill

Nope, it doesnt plane... it just skims across the water....... (well it did)