Semi Displacement advice

everyone can get defensive over their boats, choice of hull etc, I mean there is no doubt that in the absolute worst conditions semi displacement, or full displacement is what you want.. however a planning hull up to a point can handle rough weather with aplomb, and many folk on here with planning hulls will have had there hairy moments in rough weather and thought that their boats looked after them and did well. There are some new boats like Axopars that may well scream over any waves at ridiculous speeds so perhaps planning hulls are going to change preconceptions going forward..
But most folk don't go out in motorboats when the weather is terrible, so planning hulls a good choice for many. I grew up sailing and out in all weathers up to a breezy F12 which was memorable so when we have planed to go somewhere we go, I don't want to be dictated to by the weather and most of the time I am just commuting between Hamble and Yarmouth so well protected in the Solent. Couple of poor quality vid's below, both taken in F8's, first one steady 35knots gusting to 48knots by the time we reached Yarmouth, wind on our Port side. Second & third video taken on same trip, that was a steadier wind at 35knots wind gusting to 42, but wind on the nose and tide pushing us, so not ideal as 3rd video shows when going past Beaulieu it gets lumpy. Folks that know the Solent will know the short wave frequency you have to put up with, much prefer a large swell, for the Solent you would more comfort from a 40ft'er+..

Both these were filmed on Saturdays in August, but 3 years apart. Have a look at the amount of other boats you see..

https://www.youtube.com/watch?v=Y_uTHWHv1e4


Both these next vid's same day and are filmed about 10 minutes apart..
https://www.youtube.com/watch?v=2GenPu55QT0


https://www.youtube.com/watch?v=1iZCzeLCPYE


So, would these have been more comfortable in a 31 foot planning hulled sports cruiser? I have never been in one, so you tell me!
 
Here you go Aberdovey Bar, zero wind forecast, try that in a force 8

https://youtu.be/b5gE0dKoDGo

Aberdovey is an annual holiday destination for us during the kids summer holidays. The bar has it's own difficulties and can be quite exciting. For us we either have to take the bar at suboptimal times or Bardsey Sound. Generally we take the bar sub optimally as it is far worse coming in than going out.
 
everyone can get defensive over their boats, choice of hull etc, I mean there is no doubt that in the absolute worst conditions semi displacement, or full displacement is what you want.. however a planning hull up to a point can handle rough weather with aplomb, and many folk on here with planning hulls will have had there hairy moments in rough weather and thought that their boats looked after them and did well. There are some new boats like Axopars that may well scream over any waves at ridiculous speeds so perhaps planning hulls are going to change preconceptions going forward..
But most folk don't go out in motorboats when the weather is terrible, so planning hulls a good choice for many. I grew up sailing and out in all weathers up to a breezy F12 which was memorable so when we have planed to go somewhere we go, I don't want to be dictated to by the weather and most of the time I am just commuting between Hamble and Yarmouth so well protected in the Solent. Couple of poor quality vid's below, both taken in F8's, first one steady 35knots gusting to 48knots by the time we reached Yarmouth, wind on our Port side. Second & third video taken on same trip, that was a steadier wind at 35knots wind gusting to 42, but wind on the nose and tide pushing us, so not ideal as 3rd video shows when going past Beaulieu it gets lumpy. Folks that know the Solent will know the short wave frequency you have to put up with, much prefer a large swell, for the Solent you would more comfort from a 40ft'er+..

Both these were filmed on Saturdays in August, but 3 years apart. Have a look at the amount of other boats you see..

https://www.youtube.com/watch?v=Y_uTHWHv1e4


Both these next vid's same day and are filmed about 10 minutes apart..
https://www.youtube.com/watch?v=2GenPu55QT0


https://www.youtube.com/watch?v=1iZCzeLCPYE


So, would these have been more comfortable in a 31 foot planning hulled sports cruiser? I have never been in one, so you tell me!

Not defensive, irked maybe, but I take huge solace that your F8 vids are no better or no worse than mine and I happily do that without qualm in the knowlege that once past a hellish stretch I can find a windward shore somewhere around the island of Anglesey to rest up, throw the anchor out and relax. In fact if I can be quite blunt the short chop of an F4 is quite often far harder going than a F6 or F8. Yup. Not a word of a lie. F4's can be quite miserable indeed.
 
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Next threads coming to an internet forum near you from Skipper BruceK to include

1. My family won't come boating with me anymore
2. My hull has stress fractures
3. Bog came loose and went flying about the cabin
 
Next threads coming to an internet forum near you from Skipper BruceK to include

1. My family won't come boating with me anymore
2. My hull has stress fractures
3. Bog came loose and went flying about the cabin

:D

3. Fridge came loose and went flying about the cabin.

I have absolutely no qualms about the structural integrity of my boat. Nor would you if you saw it. Built like a brick outhouse and with a layup that brings her disp. up to 8300 kg in a 34 foot sports boat. In the world of weird the family wont go boating when it's millpond calm and the mist is in. That is when they get seasick. The wife is more pro boat than I and the kids may not like the journey but they absolutely love the destinations and are quite happy to accept the rough with the smooth. Your mileage of course may vary :p

sWBVi92.jpg
 
:D

3. Fridge came loose and went flying about the cabin.

I have absolutely no qualms about the structural integrity of my boat. Nor would you if you saw it. Built like a brick outhouse and with a layup that brings her disp. up to 8300 kg in a 34 foot sports boat. In the world of weird the family wont go boating when it's millpond calm and the mist is in. That is when they get seasick. The wife is more pro boat than I and the kids may not like the journey but they absolutely love the destinations and are quite happy to accept the rough with the smooth. Your mileage of course may vary :p

sWBVi92.jpg

I was pulling your leg, whatever works for you is fine with me.
 
Anyway. Talking about F4's being worse at times....

just to bring a point home. 50nm of this was miserable. How the SC clutches didn't burn out is a testament to Volvo

 
What is the intermittent whining sounds you can here in all the videos Bruce? Is it a supercharging coming in and out?

yes. Either as the props unload cresting a wave when at displacement speeds and 1500 rpm or when the motor loads the SC's will kick in. The mobile phone amplifies the sound, but it is annoying nonetheless and I am at pains to avoid it but sea state dictates speed and the clutches will sometimes take a hammering.
 
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yes. Either as the props unload cresting a wave when at displacement speeds and 1500 rpm or when the motor loads the SC's will kick in. The mobile phone amplifies the sound, but it is annoying nonetheless and I am at pains to avoid it but sea state dictates speed and the clutches will sometimes take a hammering.

Thanks. I’ve heard talk on this forum of SC whine but really heard it for myself. Am I right to assume that the more modern D series engines with a SC are not as noticeable?
 
I was the OP and thank you all for you valuable experience and input. Portofino – thanks for comments and videos. There seems to be a strong vote for a planning hull with good deadrise (deep V) and shaft drive. Helpful comments from Firefly625, Keith-I and Bandit. Weather conditions around Channel Islands very relevant to here in Lyme Bay (particularly in southerlies and easterlies). The comments that all boats are compromises are particularly true in boating and while I do not choose to go out in particularly bad weather even “ordinary” poor weather can make a small boat uncomfortable.

There is an interesting discussion on Shannon lifeboat design here:
https://www.maritimejournal.com/new...aunch/rnlis-latest-lifeboat-ready-for-service

“The hull forms considered included a semi-displacement round bilge type with chine rails and a deep ‘V’ prismatic hull form. The eventual choice was for a double chine, warped form accommodating a wide, stable working platform with flat aft planing sections, high angle of deadrise amidships and a fine entry forward”.

But I am after a cruising boat not a lifeboat. I want a comfortable boat about 32-34ft or thereabouts that is going to live on a mooring rather than in a marina and cruise along the UK South Coast and Channel Islands, Scilly Isles etc. Being able to sleep reasonably soundly in an anchorage is also a consideration together with good guard rails at a reasonable height (not knee high apologies) and good solid deck hardware and anchoring gear. So a sports cruiser is not what `I am looking for. Neither do I need a flybridge (but have no objection other than cost, weight and windage). The question I suppose I have is what pilot house cruisers with high deadrise angle planing hulls and good deck gear should i consider and can I potter with them as well as 20kts+

I must admit I hanker after a Hardy 32 as a (rather skewed) compromise. Its an SD that is more biased towards planing than many SDs but it still seems to have the weight to carry it through a head sea. I looked at a few stats:

Disp Engines (typ)
Hardy 32 6.5 t 2x250
Aquastar 33 7.0 t 2x225
Humber 34 8.2 t 2x225
Nimbus 320 3.7 t 1x230
M. Fisher 805 3.3 t 1x200

The SDs in my size range (including my existing Merry Fisher 805) see to break down into two categories - heavy displacement SD vessels with well known sea keeping characteristics and a pilot boar heritage and lighter displacement SDs that have a "lively" ride. I guess that for comfort and the ability to potter and the ability to lay easily in an anchorage the heavier displacement vessels are the ones to choose - rather like a yacht but without the sails!!

Thanks to all
Failcon
 
Hi Failcon,

Here's one unique opportunity to Nordic tug 32 highly seaworthy boats and the popular "Trawler" US / Canada demanding the coastline as you do in the UK. LOA 34'2", LWL 32 weight about 8000kg + Fuel 776litres, water 376 litres.

1 x 280hp and max 17kn and normal cruising speed about 7kn / +1000nm 14kn/ nm? or at any speed, fuel consumption vs speed is a fairly linear increase, at least in the NT37 model.. The boat has been built heavily and with high quality eg hull was a guarantee for 10 years blisters and others. These boats were imported (UK) to Europe and for CE-B sertifications.

NT 32 sale west Scotland
https://seattle.boatshed.com/nordic_tugs_32-boat-212643.html

Rewies, https://www.soundingsonline.com/boats/nordic-tug-32

Video rewiew and sea trial second hand NT32
https://youtu.be/aSDv-rRR1gw

NBs
 
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