Small SIB sea worthiness

[ben324]

Hi

I am new to this forum.

I am thinking of buying a small SIB for urbex (exploring abandoned buildings and forts) that are out at sea.

I am wanting to do this as cheaply as I can. I have seen some small SIBs, such as ones 2.7 meters long, going for a good price.

After looking through the forum, it seems most people have far bigger ones than this.

My question is how practical are SIBs under 3 meters. Can I fit 2 people in one, and can they cope out a sea 10 miles away from land?

Also, do smaller SIBs go faster? How fast would a 2.7 meter SIB with 2 adults (totaling 150 kg) with a 10HP engine go?

[benhben]

All sizes of sibs are used in the sea. Sea fishing from a SIB is a popular hobby. I would say the boat wont be the issue out at sea but the knowledge and experience of the person operating it will be.

Have a look at outboards also. They will likely be more expensive than the boat itself.

Not sure id dare go 10 miles off shore in my sib, although i am a novice .

[Fenlander]

Hi Ben324 and welcome to the forum.

These sorts of questions are a bit scary in some ways... assuming you have no boating experience on the sea then 10mls out in any smallcraft needs a fair amount thought... never mind in something under 3m with two folks.

We have a member on here (The Gurnard) who operates a 2.7m (small RIB not SIB but effectively similar) off the West coast of Scotland in some challenging waters but he knows those waters with some 55+yrs experience. He is just one up... there is little room for two folks in a 2.7m and in difficult sea conditions two folks would make it feel well loaded.

Regarding speed... no the shorter/smaller a SIB is doesn't mean it will always be faster. It may be for the same load and outboard HP a 3-3.2m will go better.

If you really want to go 10mls out Fort exploring I'd go for a 3.8m with 15HP as a minimum outfit for two folks... get some training and work up the on-sea experience over some years possibly buddying with an experienced sibber for a few runs out... and research into all the advised safety kit.

How fast is 2.7m with a 10HP? Perhaps 17kts one up in smooth conditions. Often around the UK coast though the usual short chop encountered will limit the speed of a SIB this size or you'll be bounced out.

David

[The Gurnard]

Hi Ben..welcome to the forum.

As Fenlander mentions ..my favourite boat is a 2.75m F Rib and I have 60 years of experience of small boats at sea. I have travelled the whole west coast of Scotland in the wee inflatable ...bar a couple of pinch points with strong tides and extreme remoteness.

I would not consider going 10miles out to sea in it though. Im always within swimming or rowing distance of the coast. While it is true going 10 miles out in a flat calm is as feasible as 10 miles along the coast, the sea never stays still for long.

Once you see your first 2m high wave heading for you with a breaking top..you will know why I wont go so far in a small boat. You may think a 2m high wave is very rare on a nice day until you realise even a small tour boat or fishing boat can easily kick up such a wake... and a fast car ferry has a terrifying wake .. so perhaps now you can see why I don’t recommend it. I don’t know your area but suspect there will be many such boats and ships around a few miles off London ? Large tankers etc wont see you so you also risk getting run over

I do go regularly to islands with 10 mile open sea crossings but that is in a 4.3m boat with an extra outboard should the main outboard stop working..have vhf radio and PLB plus a drysuit as even a 4.3m inflatable is a wet cold experience for any length of time in moderate conditions.I also have vast experience of both the boat and the areas I go too

A 2.75 boat in my opinion ..although great fun for one ..is not big enough for two at sea..yes it will take two or more folk in sheltered waters out to bigger boats..but not really large enough for two in open sea. A small boat sits far lower in water with two than with one..so while the tube top may be out the water by 12” with one person..it may be only 6” out the water with two on board ..therefore it fills with water far easily.

A 2.75 boat can often be slower than a 3.75 meter boat simple because it has more drag. One reason it has more drag is already mentioned..it will sit lower in the water than a 3.75m with same load. There are other reasons.

Yup..with two folks on a nice calm day expect speeds as mentioned by fenlander..but in reality with two on board unless a calm day .. expect to be going around 5 miles per hour or be flooded with waves or bounced out the boat.

Hope that helps a bit ..but for clarification..IMO it would be silly going 10 miles out in a 2.75 boat especially as a novice. I certainly don’t do it even with my experience

[Allye]

I’d have to agree with the above. You’d have to be pretty ballsy to take a <3m boat 10miles offshore. With any sort of chop it would take you at least an hour to return to shore, the ocean can change beyond belief in an hour, sometime poorly forecasted.

Having said all that, I’d fully encourage you getting out and about in a sib, the package difference between 3m+ and smaller isn’t huge so makes sense to go larger. Over power it slightly with a reliable 2 stroke and you’ll be laughing.

[Max...]

Forget 10 miles offshore in any SIB as an amateur - not a good idea.

For any SIB in typical UK F3/4 conditions I'd go minimum 3.4m and 15hp.

[Tim M]

Taking a 2.7m RIB with a 10hp on the back that far out particularly with little or no experience would in my opinion be somewhat foolish. Even the best 2.7m RIB is going to be uncomfortable in anything other than glassy flat seas. Remember that these boats are primarily designed as tenders and runabouts rather than for offshore adventuring!

Harry Dwyer has made a very good Youtube series on starting out with small RIB ownership. With no apparent prior experience he has refurbished a 4m RIB and is slowly taking it all the way around the UK. Plenty you can gain from watching some of his videos about the limitations of small boats.

https://www.youtube.com/watch?v=E8ECm7k1jzY&t=45s

[Locozodiac]

The shorter in size the Sib the more will drag. A larger one say minimum a 320 will plane faster that a 2.7 mtr with same motor..

Happy Boating

[Mikefule]

Smaller boats are slower, wetter, and less comfortable.

No one 10 miles out at sea ever wished their boat was a bit smaller.

It's not just the length of the boat, but the width (beam), and the diameter of the tubes — as well as the space on the transom for a spare outboard and space inside for safety kit, extra waterproofs, radio, anchor(s), flares, hot drink, food and water.

If your outboard fails and you can't anchor, you drift downwind. If that's an offshore wind, that is one problem, and if it's onshore, it can be a different problem. A small boat drifting sideways in surf will flip over.

All boating carries some risk. The further out to sea you are, the greater the risks, because you have further to make it back if the weather deteriorates. By the time you're back, the conditions at the slipway/beach may be far worse than when you set off. Recovering a boat in breaking waves when you're cold, tired, frightened and alone is not an inviting prospect.

As Gurnard mentioned, even the wake of a large vessel passing you will be a substantial wave. I've been out among the western isles and felt a 40ft boat rocking because a big ferry has gone past.

On a good day with calm conditions, a 250 will easily cover 20 miles (10 miles each way) although you'll have a numb backside by the time the trip is finished. However, add a small choppy sea and your speed is reduced drastically, eventually down to "displacement speed" (not planing) which is something like 5 or 6 knots in such a small boat. So suddenly your "10 miles out" is "2 hours from safety."

Navigation. 10 miles out and 10 miles back. A few degrees off course could put you 2 miles along the shore from where you set off. The visibility is deteriorating, the shore looks remarkably similar, which way is the slipway now?

I've done some daft things in bigger SIBs than that, and looking back, I took risks and got away with it. However, I can assure you I would never have considered going 10 miles off shore without a spare engine already on the transom, and full safety kit — which pretty much excludes any SIB under about 4 metres or so.

[ben324]

Thank you for all of your advise. All of your detailed descriptions have helped me a lot. I am very new to this.

I most likely won't go 10 miles out, at least until I have had a lot of practice close to the shore.

With a 15 HP engine, I have read on this forum that they are very heavy.

Are their any places to buy SIBs other than ebay. There is little choice on ebay, or is it the case of looking regularly to see what appears.

For a 3.4 meter SIB from a known brand and a 15 HP engine, how much would that cost second hand. I am hoping it would be under £1000 but I don't think that is possible.

A SIB seems like a lot of fun.

[Mikefule]

Originally Posted by ben324

Thank you for all of your advise. All of your detailed descriptions have helped me a lot. I am very new to this.

I most likely won't go 10 miles out, at least until I have had a lot of practice close to the shore.

With a 15 HP engine, I have read on this forum that they are very heavy.

Are their any places to buy SIBs other than ebay. There is little choice on ebay, or is it the case of looking regularly to see what appears.

For a 3.4 meter SIB from a known brand and a 15 HP engine, how much would that cost second hand. I am hoping it would be under £1000 but I don't think that is possible.

A SIB seems like a lot of fun.

If you're talking in £ then I guess you're in the UK? If so, look on apolloduck.co.uk for boats, engines and prices.

A 9.9 or a 15 weigh about the same (some variation between manufacturers). I can lift my 9.9 and carry it from the car to the slipway "in one go" or lift it back into the car, unassisted, but it's a struggle.

One thing with an engine over about 6 or 8 hp is it needs a remote tank, and that means an extra item to carry, and extra clutter in the boat. Smaller engines have built in tanks. Slight disadvantage of a built in tank is refuelling is tricky out on the water, but you can usually get round that with careful planning. It's tricky, but not impossible.

My 310 will plane on flat water with just me on board using my 3 hp 2 stroke.

Once the water gets choppy, going fast in a small SIB is exhilarating but tiring. For a long day, chugging at displacement speeds is often drier and more comfortable — and can be safer.

General rule of SIBs: small is better for the 99% of the time you're not on the water: paying for it, insuring it, storing it, transporting it, pumping it up, dragging it across the beach or up the slipway. Bigger is better for most of the time that you're on the water as bigger is drier, more comfortable and relaxed. (However, a smaller one will go into small gaps between rocks, up narrower arms of the river, etc.)

General rule of engines: bigger is great when you have the opportunity to go fast, but that is a surprisingly small amount of the time. Smaller is better for all the other times: paying for it, insuring it, storing it, transporting it, maintaining it, carrying it... you get the idea.

For a solo general purpose set up, something like a 310 to 340 sized hull with something like a 6hp or 8hp engine will do most things that you would sensibly ask of it. It will carry 3 adults, or give one person room to stretch out and have a kip. It will fit in the boot of your car. It won't take too long to assemble or disassemble. It will go reasonably fast in decent conditions, and cope with reasonably difficult conditions.

If I made my choice again, I'd put more emphasis on tube diameter, for comfort and dryness.

[paintman]

Displacement speed for a 2.7 metre boat is a tad under 4 knots.
Something that needs to be considered if you are buying a displacement hull boat.
If you need to get home against a falling tide - esp if against wind as well - then you might find the combination is equal to or greater than your boat's max speed so you'll finish up going nowhere or backwards with diminishing fuel.
Seen this with small hire boats (12 foot IIRC so under 5 knots) that used to be available where I go. Hirers were told not to go beyond a certain head. Occasionally come evening one would be missing. We knew exactly where they'd be - sat in the tidal run off the head, flat out going nowhere - & just used to take a bigger boat out to tow them in.

[Fenlander]

>>>A 9.9 or a 15 weigh about the same

As the OP is new to all this I'll expand a little...

If you are looking at older 2-strokes pre 2007 it's true the 9.9hp and 15hp models are often the same motors with just tuning differences so weigh the same usually around 35/36kg and this is about the upper limit of comfort to handle for many.

(Remember this weight is nothing to do with what you can dead lift... its trying to handle a often wet/slippery top heavy thing sometimes on a sloping and slimy slipway or over rocks)

The Tohatsu 2-stroke range of this era stands out as a little different in that their 9.9hp 2-stroke weighs the same as their 15/18hp models at 40kg+ so is a bit heavy... yet they do a 9.8hp based on the 6/8hp models weighing 26kg so that's a very popular motor for smaller/medium SIBs.

Once you move onto 4-strokes which are always heavier things change a bit in that the 15hp models are usually down tuned 20hp motors and they weigh around 46kg if the latest Efi models but often the earlier used 15hp 4-strokes are loads heavier which is just too much to swing about for SIB use.

9.9hp 4-stroke models vary in weight some being similar to the 15/20hp in weight... others a bit lighter. Mike above has the Mariner 9.9hp 4-stroke which is a popular motor... this weighs about 38kg so you can see it's slightly heavier than a 15hp 2-stroke.

There's a lot in the detail with these choices!

Re budget if Covid wasn't about this time of year you could spend £1000 or more on a tidy Mercury/Mariner/Yamaha/Tohatsu 9.9/15hp 2-stroke and often similar on the light Tohatsu 9.8hp 2-stroke so all the budget gone on the motor. Covid has already shown some bargains but you're still unlikely to get such a motor under £750-£800.

Packages of SIBs being sold with motors can be a good buy though but you'll have to be exceptionally lucky to get a sensible sized SIB with 9.9/15hp in this budget.

Remember there will be an extra spend on safety kit such as lifejackets, flares, radio, anchor, ropes etc.

[Pikey Dave]

Originally Posted by Fenlander

>>>A 9.9 or a 15 weigh about the same

As the OP is new to all this I'll expand a little...

If you are looking at older 2-strokes pre 2007 it's true the 9.9hp and 15hp models are often the same motors with just tuning differences so weigh the same usually around 35/36kg and this is about the upper limit of comfort to handle for many.

(Remember this weight is nothing to do with what you can dead lift... its trying to handle a often wet/slippery top heavy thing sometimes on a sloping and slimy slipway or over rocks)

The Tohatsu 2-stroke range of this era stands out as a little different in that their 9.9hp 2-stroke weighs the same as their 15/18hp models at 40kg+ so is a bit heavy... yet they do a 9.8hp based on the 6/8hp models weighing 26kg so that's a very popular motor for smaller/medium SIBs.

Once you move onto 4-strokes which are always heavier things change a bit in that the 15hp models are usually down tuned 20hp motors and they weigh around 46kg if the latest Efi models but often the earlier used 15hp 4-strokes are loads heavier which is just too much to swing about for SIB use.

9.9hp 4-stroke models vary in weight some being similar to the 15/20hp in weight... others a bit lighter. Mike above has the Mariner 9.9hp 4-stroke which is a popular motor... this weighs about 38kg so you can see it's slightly heavier than a 15hp 2-stroke.

There's a lot in the detail with these choices!

Re budget if Covid wasn't about this time of year you could spend £1000 or more on a tidy Mercury/Mariner/Yamaha/Tohatsu 9.9/15hp 2-stroke and often similar on the light Tohatsu 9.8hp 2-stroke so all the budget gone on the motor. Covid has already shown some bargains but you're still unlikely to get such a motor under £750-£800.

Packages of SIBs being sold with motors can be a good buy though but you'll have to be exceptionally lucky to get a sensible sized SIB with 9.9/15hp in this budget.

Remember there will be an extra spend on safety kit such as lifejackets, flares, radio, anchor, ropes etc.

^^^^^^^^
Wot he said re. Budget.
Don’t think that you’re going to spend a grand & that’s the end of it. It’s the thin end of a very thick wedge.

[benhben]

Originally Posted by Mikefule

I've done some daft things in bigger SIBs than that, and looking back, I took risks and got away with it. However, I can assure you I would never have considered going 10 miles off shore without a spare engine already on the transom, and full safety kit — which pretty much excludes any SIB under about 4 metres or so.

Without meaning to hijack the thread, do many SIB owners carry a spare outboard in the sea?

I have a 3.4m SIB with a 15hp Tohatsu. Mainly used in the lake district but also do some sea fishing staying within a mile or so of shore. There is zero space for a spare outboard!

I would be relying on my safety equipment in the event of a failure.

[Fenlander]

Personally I don't carry an aux and never will with a SIB. But I do make sure my OB is perfectly maintained and most important on each trip I take account of wind and tide to understand where those might take me if the motor stopped and I went for a slow paddle in. I also judge the other water users (as in amount and proximity of) in the area that day so I have a good idea what help a radio call or waving a T-shirt on extended boat hook might bring.

So if the wind and tide are not in my favour and there are few other folks about I adjust my route accordingly.

[Ferryman]

If you want a good laugh, look over some of the old threads on this subject. Some people have definite opinions - almost became personal here and there!![emoji23][emoji23]

[spartacus]

I'm glad you've reconsidered the 10 miles offshore suggestion.

I thought I was going to have to regale tales of fishing in my RIB a couple of years ago off the coast of Lewis in inky black Atlantic waters when a 5m minke whale surfaced right next to me, and I did an impression of Roy Schneider 'you're going to need a bigger boat'!

Agree with Pikey Dave on the budget. Now is not the time to buy. You need to travel, and right now a walk around the block is an adventure. Hang fire is my advice. Regards places to buy, there's more than EBay. Check out this 90s classic Futura. Personally I'd want the aluminium HD floor version for rigidity.

https://www.boatsandoutboards.co.uk/...-futura/286515

[Mikefule]

Originally Posted by benhben

1) Without meaning to hijack the thread, do many SIB owners carry a spare outboard in the sea?

2) I would be relying on my safety equipment in the event of a failure.

(My numbering of snips from your comment)

1) No, virtually none, but then virtually none go 10 miles out to sea, which is the context of my comment.

2) So would I, which is why I would not be 10 miles out!

So my point was, if I were going 10 miles out, I would want a big enough boat to have a reserve engine already mounted on the transom.

Many dive club ribs have twin engines rather than one big one so they can limp back home if one fails.

[Callum B]

Theres a lot of wisdom gone before, and i understand the question, however, I would suggest that all the best bits are within ¼ mile of the land.

Long offshore passages, which ive done many of, are somewhat dull imo.